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© 2012 Scientific American Illustrations by Bryan Christie M E D I C I N E THE ULTIMATE SOCIAL NETWORK Researchers who study the friendly bacteria that live inside all of us are starting to sort out who is in charge—microbes or people? By Jennifer Ackerman June 2012, ScientificAmerican.com 37 © 2012 Scientific American © 2012 Scientific American 38 Scientific American, June 2012 Over the past 10 years or so, however, researchers have demonstrated that the human body is not such a neatly self- sufficient island after all. It is more like a complex ecosystem— a social network—containing trillions of bacteria and other mi- croorganisms that inhabit our skin, genital areas, mouth and especially intestines. In fact, most of the cells in the human body are not human at all. Bacterial cells in the human body outnumber human cells 10 to one. Moreover, this mixed com- munity of microbial cells and the genes they contain, collective- ly known as the microbiome, does not threaten us but offers vi- tal help with basic physiological processes—from digestion to growth to self-defense. So much for human autonomy. Biologists have made good progress characterizing the most prevalent species of microbes in the body. More recently, they have begun to identify the specific effects of these residents. In so doing, they are gaining a new view of how our bodies func- tion and why certain modern diseases, such as obesity and au- toimmune disorders, are on the rise. OUT OF MANY, ONE when people think of microbes in the body, they usually think of pathogens. Indeed, for a long time researchers focused solely on these harmful bugs and ignored the possible importance of more benign ones. The reason, argues biologist Sarkis K. Mazmanian of the California Institute of Technology, is our skewed view of the world. “Our narcissism held us back; we tended to think we had all the func- tions required for our health,” he says. “But just because microbes are foreign, just because we acquire them through- out life, doesn’t mean they’re any less a fundamental part of us.” Indeed, all humans have a microbi- ome from very early in life, even though they do not start out with one. Each individual acquires his or her own community of commensals (from the Latin for “sharing a table”) from the sur- rounding environment. Because the womb does not normally contain bacteria, newborns begin life as sterile, singular beings. But as they pass through the birth canal, they pick up some of Mom’s commensal cells, which then begin to multiply. Breast- feeding and handling by proud parents, grandparents, siblings, and friends—not to mention ordinary contact with bedsheets, blankets, and even pets—quickly contribute to an expanding ark of microbes. By late infancy our bodies support one of the most complex microbial ecosystems on the planet. For the past five years or so scientists have been working to characterize the nature of this ecosystem. ...

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© 2012 Scientific American Illustrations by Bryan Christie M E D I C I N E THE ULTIMATE SOCIAL NETWORK Researchers who study the friendly bacteria that live inside all of us are starting to sort out who is in charge—microbes or people? By Jennifer Ackerman June 2012, ScientificAmerican.com 37 © 2012 Scientific American © 2012 Scientific American 38 Scientific American, June 2012 Over the past 10 years or so, however, researchers have demonstrated that the human body is not such a neatly self- sufficient island after all. It is more like a complex ecosystem— a social network—containing trillions of bacteria and other mi-
croorganisms that inhabit our skin, genital areas, mouth and especially intestines. In fact, most of the cells in the human body are not human at all. Bacterial cells in the human body outnumber human cells 10 to one. Moreover, this mixed com- munity of microbial cells and the genes they contain, collective- ly known as the microbiome, does not threaten us but offers vi- tal help with basic physiological processes—from digestion to growth to self-defense. So much for human autonomy. Biologists have made good progress characterizing the most prevalent species of microbes in the body. More recently, they have begun to identify the specific effects of these residents. In so doing, they are gaining a new view of how our bodies func- tion and why certain modern diseases, such as obesity and au- toimmune disorders, are on the rise. OUT OF MANY, ONE when people think of microbes in the body, they usually think of pathogens. Indeed, for a long time researchers focused solely on these harmful bugs and ignored the possible importance of more benign ones. The reason, argues biologist Sarkis K. Mazmanian of the California Institute of Technology, is our skewed view of the world. “Our narcissism held us back; we tended to think we had all the func- tions required for our health,” he says. “But just because microbes are foreign, just because we acquire them through- out life, doesn’t mean they’re any less a fundamental part of us.” Indeed, all humans have a microbi- ome from very early in life, even though they do not start out
with one. Each individual acquires his or her own community of commensals (from the Latin for “sharing a table”) from the sur- rounding environment. Because the womb does not normally contain bacteria, newborns begin life as sterile, singular beings. But as they pass through the birth canal, they pick up some of Mom’s commensal cells, which then begin to multiply. Breast- feeding and handling by proud parents, grandparents, siblings, and friends—not to mention ordinary contact with bedsheets, blankets, and even pets—quickly contribute to an expanding ark of microbes. By late infancy our bodies support one of the most complex microbial ecosystems on the planet. For the past five years or so scientists have been working to characterize the nature of this ecosystem. The task has been dev- ilishly difficult. The bacterial cells in the intestines, for example, have evolved to grow in the crowded, oxygen-free environment of the gut, so many species do not survive well in the lonely ex- panse of a petri dish. Researchers have gotten around this prob- lem, however, by studying the genetic instructions, the strands of DNA and RNA, found within a microbe rather than the whole cell itself. Because DNA and RNA can be manipulated in a nor- mal, oxygenated laboratory environment, investigators can take microbial samples from the body, extract the genomic material and analyze the results. Each species of commensal bacteria has a signature, it turns out—its own unique version of a gene (known as the 16S ribo- B iologists once thought that human beings were phys iological islands, entirely capable of regulating their own internal workings. Our bodies made all the enzymes needed for breaking down food and using its
nutrients to power and repair our tissues and organs. Signals from our own tissues dictated body states such as hun- ger or satiety. The specialized cells of our immune system taught themselves how to recognize and attack dangerous microbes— pathogens—while at the same time sparing our own tissues. Jennifer Ackerman is an award-winning science writer and author of Ah-Choo! The Uncommon Life of Your Common Cold (Twelve, 2010). She is now writing a book about the intelligence of birds. I N B R I E F Bacterial cells in the body outnumber human cells by a factor of 10 to 1. Yet only recently have researchers begun to elucidate the beneficial roles these microbes play in fostering health. Some of these bacteria possess genes that encode for beneficial compounds that the body cannot make on its own. Other bacteria seem to train the body not to overreact to outside threats. Advances in computing and gene se- quencing are allowing investigators to create a detailed catalogue of all the bacterial genes that make up this so- called microbiome. Unfortunately, the inadvertent de- struction of beneficial microbes by the
use of antibiotics, among other things, may be leading to an increase in auto- immune disorders and obesity. SO U RC E: E LI N O R AC KE RM A N © 2012 Scientific American June 2012, ScientificAmerican.com 39 somal RNA gene) that codes for a particular RNA molecule found in the ribosomes, the protein-making machinery of cells. By determining the sequence of this gene, scientists are creating a catalogue of the entire human microbiome. In this way, they can glean which species exist in our bodies and how the precise
combination of species may differ from one person to another. The next step is to analyze other genes found in the microbial community to determine which ones are active in people and what functions they perform. Again, that chore is a tall order be- cause of the great number of species and because their genes get mixed together in the extraction process. Determining whether a specific bacterial gene is active (or expressed) in the body is rela- tively straightforward; figuring out to which species that partic- ular gene belongs is not. Fortunately, the development of ever more powerful computers and ultrafast gene sequencers in the first decade of the 21st century has turned what would once have been an impossible task of sorting and analysis into merely a very complicated one. Two separate groups of scientists, one in the U.S. and the other in Europe, have harnessed this new technology to enu- merate the bacterial genes within the human body. In early 2010 the European group published its census of microbial genes in the human digestive system—3.3 million genes (from more than 1,000 species)—about 150 times the 20,000 to 25,000 genes in the human genome. Research into the nature of the human microbiome has yielded many surprises: no two people share the same microbial makeup, for instance—even identical twins. This finding may help unravel a mystery presented by the Human Genome Proj- ect, which confirmed that the human DNA of all people the world over is 99.9 percent alike. Our individual fates, health and perhaps even some of our actions may have much more to do with the variation in the genes found in our microbiome than in our own genes. And
although the microbiomes of different people vary markedly in the relative number and types of species they contain, most people share a core complement of helpful bacterial genes, which may derive from different spe- cies. Even the most beneficial bacteria can cause serious illness, however, if they wind up somewhere they are not supposed to be—for example, in the blood (causing sepsis) or in the web of tissue between the abdominal or- gans (causing peritonitis). FRIENDS WITH BENEFITS the first inkling that beneficial bugs might do us good came decades ago during research on digestion and the production of vitamins in the guts of animals. By the 1980s investiga- tors had learned that human tissue needs vi- tamin B 12 for, among other things, cellular en- ergy production, DNA synthesis and the man- ufacture of fatty acids and had determined that only bacteria synthesize the enzymes needed to make the vitamin from scratch. Similarly, scientists have known for years that gut bacteria break down certain components of food that would otherwise be indigestible and would pass out of the body un- used. Only in the past few years, however, have they learned the juicy details: two commensal species in particular play major roles in both digestion and the regulation of appetite. Perhaps the prime example of a helpful bug sounds like it
was named after a Greek sorority or fraternity. Bacteroides the- taiotaomicron is a champion carbohydrate chomper, capable of breaking down the large, complex carbohydrates found in many plant foods into glucose and other small, simple, easily digest- ible sugars. The human genome lacks most of the genes re- quired to make the enzymes that degrade these complex carbo- hydrates. B. thetaiotaomicron, on the other hand, has genes that code for more than 260 enzymes capable of digesting plant mat- ter, thus providing humans with a way to efficiently extract nu- trients from oranges, apples, potatoes and wheat germ, among other foods. Fascinating details about how B. thetaiotaomicron interacts with, and provides sustenance to, its hosts come from studies of mice raised in a completely sterile environment (so they had no microbiome) and then exposed only to this particular strain of microbes. In 2005 researchers at Washington University in St. Louis reported that B. thetaiotaomicron survives by consuming complex carbohydrates known as polysaccharides. The bacteria ferment these substances, generating short-chain fatty acids (es- sentially their feces) that the mice can use as fuel. In this way, bacteria salvage calories from normally indigestible forms of carbohydrate, such as the dietary fiber in oat bran. (Indeed, ro- dents that are completely devoid of bacteria have to eat 30 per - M O R E T H A N H U M A N Buddy, Can You Spare a Gene? Helping hands: The number of genes distributed among the friendly bacteria that live inside people’s bodies and on their skin far outnumbers the number of genes we inherit from our parents. Researchers are figuring out in greater detail which of these microbial genes benefit their human hosts and how.
Human: 20,000 –25,000 genes Gut microbiome: 3.3 million genes © 2012 Scientific American 40 Scientific American, June 2012 Mouth, Pharynx, Respiratory SystemStreptococcus viridans Candida albicans Neisseria sicca Streptococcus salivarius Stomach Bacteroides fragilis Streptococcus thermophilus Helicobacter pylori Lactobacillus
casei Lactobacillus gasseri Lactobacillus reuteri Bacteroides thetaiotaomicron Escherichia coli Intestines Urogenital tract © 2012 Scientific American June 2012, ScientificAmerican.com 41 M I C R O B I A L L O C A T O R M A P O F T H E B O D Y Different Species for Different Reasons Various types of microbes congregate everywhere in and on the human body. Their presence maintains their host’s health in part by making it hard for disease-causing germs to gain access to the body. Several species, such as Bacteroides fragilis, also perform specific useful functions, including aiding in the development and regulation of the immune system (below, right).
Case Study: How One Bacterial Species Helps Studies on mice raised in sterile conditions reveal that B. fragilis bacteria are crucial to maintaining the health of the intestines. In one experiment, germ-free mice that were given a strain of B. fragilis bacteria that produced the complex carbohydrate polysaccharide A did not develop inflammation of the intestine (colitis), whereas mice that were given a strain of B. fragilis bacteria that did not make PSA developed chronic inflammation of the gut. Investigators showed that the presence of PSA stimulated the development of regulatory T cells that in turn switched off the inflammatory T cells, thereby restoring health. Immune cells called dendritic cells pick up a molecule called polysaccharide A (PSA) from the B. fragilis cells and present it to undifferentiated T cells. 1 The bits and pieces of PSA stimulate the undifferentiated T cells to become regulatory T cells, which in turn produce substances that tamp down the aggressive efforts of in- flammatory T cells. 2 SO
U RC E: “I N SI D E TH E M IC RO BI A L A N D IM M U N E
LA BY RI N TH : G U T M IC RO BE S: F RI EN D S O R FI EN D
S? ” B Y W A RR EN S TR O BE R, IN N AT U RE M ED IC IN E, V O
L. 16 ; 2 01 0 (B . f ra gi lis c as e st ud y) Urogenital tract Corynebacterium aurimucosum Ureaplasma parvum Skin Staphylococcus epidermidis
Staphylococcus haemolyticus Pityrosporum ovale Corynebacterium jeikeium Trichosporon B. fragilis PSA manufactured by B. fragilis Dendritic cell Undifferen- tiated T cell Regulatory T cellsGut Inflamed area Inflammatory T cells © 2012 Scientific American© 2012 Scientific American
42 Scientific American, June 2012 cent more calories than do rodents with an intact microbiome to gain the same amount of weight.) The study of the microbiome has even partially rehabilitat- ed the reputation of one disease-causing bacterium called Heli- cobacter pylori. Fingered by Australian physicians Barry Mar - shall and Robin Warren in the 1980s as the causative agent of peptic ulcers, H. pylori is one of the few bacteria that seem to thrive in the acidic environment of the stomach. While contin- ued use of medicines known as nonsteroidal anti-inflammatory drugs, or NSAIDs, had long been known to be a common cause of peptic ulcers, the finding that bacteria contributed to the condition was remarkable news. After Marshall’s discovery, it became standard practice to treat peptic ulcers with antibiot- ics. As a result, the rate of H. pylori–induced ulcers has dropped by more than 50 percent. Yet the matter is not so simple, says Martin Blaser, now a pro- fessor of internal medicine and microbiology at New York Uni - versity who has studied H. pylori for the past 25 years. “Like ev- eryone, I started working on H. pylori as a simple pathogen,” he says. “It took a few years for me to realize that it was actually a commensal.” In 1998 Blaser and his colleagues published a study showing that in most people, H. pylori benefits the body by help- ing to regulate levels of stomach acids, thus creating an environ- ment that suits itself and its host. If the stomach churns out too much acid for the bacteria to thrive, for example, strains of the bug that contain a gene called cagA start producing proteins that
signal the stomach to tone down the flow of acid. In susceptible people, however, cagA has an unwelcome side effect: provoking the ulcers that earned H. pylori its nasty rap. A decade later Blaser published a study suggesting that H. py- lori has another job besides regulating acid. For years scientists have known that the stomach produces two hormones involved in appetite: ghrelin, which tells the brain that the body needs to eat, and leptin, which—among other things—signals that the stomach is full and no more food is needed. “When you wake up in the morning and you’re hungry, it’s because your ghrelin lev- els are high,” Blaser says. “The hormone is telling you to eat. Af- ter you eat breakfast, ghrelin goes down,” which scientists refer to as a postprandial (from the Latin word prandium, for “a meal”) decrease. In a study published last year, Blaser and his colleagues looked at what happens to ghrelin levels before and after meals in people with and without H. pylori. The results were clear: “When you have H. pylori, you have a postprandial decrease in ghrelin. When you eradicate H. pylori, you lose that,” he says. “What that means, a priori, is that H. pylori is involved in regu- lating ghrelin”—and thus appetite. How it does so is still largely a mystery. The study of 92 veterans showed that those treated with antibiotics to eliminate H. pylori gained more weight in compar- ison to their uninfected peers—possibly because their ghrelin level stayed elevated when it should have dropped, causing them to feel hungry longer and to eat too much. Two or three generations ago more than 80 percent of Amer-
icans played host to the hardy bug. Now less than 6 percent of American children test positive for it. “We have a whole genera- tion of children who are growing up without H. pylori to regu- late their gastric ghrelin,” Blaser says. Moreover, children who are repeatedly exposed to high doses of antibiotics are likely ex- periencing other changes in their microbial makeup. By the age of 15, most children in the U.S. have had multiple rounds of anti- biotic treatment for a single ailment—otitis media, or ear infec- tion. Blaser speculates that this widespread treatment of young children with antibiotics has caused alterations in the composi - tions of their intestinal microbiome and that this change may help explain rising levels of childhood obesity. He believes that the various bacteria within the microbiome may influence whether a certain class of the body’s stem cells, which are rela - tively unspecialized, differentiate into fat, muscle or bone. Giv- ing antibiotics so early in life and thereby eliminating certain microbial species, he argues, interferes with normal signaling, thereby causing overproduction of fat cells. Could the accelerating loss of H. pylori and other bacteria from the human microbiome, along with societal trends—such as the easy availability of high-calorie food and the continuing decline in manual labor—be enough to tip the balance in favor of a global obesity epidemic? “We don’t know yet whether it’s going to be a major or minor part of the obesity story, ” he says, “but I’m betting it’s not trivial.” The widespread use of antibiotics is not the only culprit in the unprecedented disruption of the human microbiome in Blaser’s view. Major changes in human ecology over the past century have contributed as well. The dramatic increase in the past few decades in the number of deliveries by cesarean section obvi -
ously limits the transfer through the birth canal of those all -im- portant strains from Mom. (In the U.S., more than 30 percent of all newborns are delivered by C-section, and in China—land of one child per couple—the operation is responsible for nearly two thirds of all births to women living in urban areas.) Smaller family sizes throughout the world mean fewer siblings, who are a prime source of microbial material to their younger siblings during early childhood years. Even cleaner water—which has saved the lives of untold millions—exacts a toll on the human microbiome, reducing the variety of bacteria to which we are ex- posed. The result: more and more people are born into and grow up in an increasingly impoverished microbial world. A DELICATE BALANCE as the ongoing studies of B. thetaiotaomicron and H. pylori il - lustrate, even the most basic questions about what these bacte- rial species are doing in the body lead to complicated answers. Going one step further and asking how the body responds to the presence of all these foreign cells in its midst introduces even greater complexity. For one thing, the traditional understanding of how the immune system distinguishes the body’s own cells (self ) from genetically different cells (nonself ) suggests that our molecular defenses should be in a constant state of war against these myriad interlopers. Why the intestines, for example, are not the scene of more pitched battles between human immune cells and the trillions of bacteria present is one of the great, as yet unsolved mysteries of immunology. The few clues that exist offer tantalizing insights into the balancing act between the microbiome and human immune cells that has taken some 200,000 years to calibrate. Over the eons the immune system has evolved numerous checks and bal - ances that generally prevent it from becoming either too aggres - sive (and attacking its own tissue) or too lax (and failing to rec-
ognize dangerous pathogens). For example, T cells play a major role in recognizing and attacking microbial invaders of the © 2012 Scientific American June 2012, ScientificAmerican.com 43 body, as well as unleashing the characteristic swelling, redness and rising temperature of a generalized inflammatory response to infection by a pathogen. But soon after the body ramps up its production of T cells, it also starts producing so-called regulato- ry T cells, whose principal function seems to be to counteract the activity of the other, pro-inflammatory T cells. Normally the regulatory T cells swing into action before the pro-inflammatory T cells get too carried away. “The problem is that many of the mechanisms that these proinflammatory T cells use to fight infection—for example, the release of toxic compounds—end up blasting our own tissues,” says Caltech’s Mazmanian. Fortunately, the regulatory T cells produce a pro- tein that restrains the proinflammatory T cells. The net effect is to tamp down inflammation and prevent the immune system from attacking the body’s own cells and tissues. As long as there is a good balance between belligerent T cells and more tolerant regulatory T cells, the body remains in good health. For years researchers assumed that this system of checks and balances was generated entirely by the immune system. But in yet another example of how little we control our own fate, Mazmanian and oth- ers are starting to show that a healthy, mature immune system depends on the constant inter-
vention of beneficial bacteria. “It goes against dogma to think that bacteria would make our immune systems function better,” he says. “But the picture is getting very clear: the driving force behind the features of the immune system are commensals.” Mazmanian and his team at Caltech have dis- covered that a common microorganism called Bacteroides fragilis, which lives in some 70 to 80 percent of people, helps to keep the immune sys- tem in balance by boosting its anti-inflammatory arm. Their research began with observations that germ-free mice have defective immune systems, with diminished function of regulatory T cells. When the re- searchers introduced B. fragilis to the mice, the balance between the pro-inflammatory and anti-inflammatory T cells was re- stored, and the rodents’ immune systems functioned normally. But how? In the early 1990s researchers started characteriz- ing several sugar molecules that protrude from the surface of B. fragilis—and by which the immune system recognizes its pres- ence. In 2005 Mazmanian and his colleagues showed that one of these molecules, known as polysaccharide A, promotes matura- tion of the immune system. Subsequently, his laboratory re- vealed that polysaccharide A signals the immune system to make more regulatory T cells, which in turn tell the pro-inflam- matory T cells to leave the bacterium alone. Strains of B. fragilis that lack polysaccharide A simply do not survive in the mucosal lining of the gut, where immune cells attack the microbe as if it were a pathogen. In 2011 Mazmanian and his colleagues published a study in Sci - ence detailing the full molecular pathway that produces this ef-
fect—the first such illumination of a molecular pathway for mutu- alism between microbe and mammal. “B. fragilis provides us with a profoundly beneficial effect that our own DNA for some reason doesn’t provide,” Mazmanian says. “In many ways, it co-opts our immune system—hijacks it.” Unlike pathogens, however, this hi- jacking does not inhibit or reduce our immune system perfor- mance but rather helps it to function. Other organisms may have similar effects on the immune system, he notes: “This is just the first example. There are, no doubt, many more to come.” Alas, because of lifestyle changes over the past century, B. fragilis, like H. pylori, is disappearing. “What we’ve done as a society over a short period is completely change our association with the microbial world,” Mazmanian says. “In our efforts to distance ourselves from disease-causing infectious agents, we have probably also changed our associations with beneficial or - ganisms. Our intentions are good, but there’s a price to pay.” In the case of B. fragilis, the price may be a significant in- crease in the number of autoimmune disorders. Without poly- saccharide A signaling the immune system to churn out more regulatory T cells, the belligerent T cells begin attacking every- thing in sight—including the body’s own tissues. Mazmania n contends that the recent sevenfold to eightfold increase in rates of autoimmune disorders such as Crohn’s disease, type 1 diabe - tes and multiple sclerosis is related to the de- cline in beneficial microbes. “All these diseases have both a genetic component and an environ- mental component,” Mazmanian says. “I believe
that the environmental component is microbi- otic and that the changes are affecting our im- mune system.” The microbial shift that comes with changes in how we live—including a de- crease in B. fragilis and other anti-inflammato- ry microbes—results in the underdevelopment of regulatory T cells. In people who have a ge- netic susceptibility, this deviation may lead to autoimmunity and other disorders. Or at least that is the hypothesis. At this stage in the research, the correlations in humans be- tween lower microbial infections and increased rates of immune disease are only that—correla- tions. Just as with the obesity issue, teasing apart cause and effect can be difficult. Either the loss of humanity’s in- digenous bugs have forced rates of autoimmune diseases and obesity to shoot up or the increasing levels of autoimmunity and obesity have created an unfavorable climate for these native bugs. Mazmanian is convinced that the former is true—that changes in the intestinal microbiome are contributing significantly to rising rates of immune disorders. Yet “the burden of proof is on us, the scientists, to take these correlations and prove that there is cause and effect by deciphering the mechanisms underlying them,” Mazmanian says. “That is the future of our work.” WE HAVE COMPLETELY CHANGED OUR ASSOCIATION
WITH THE MICROBIAL WORLD. THERE IS A PRICE TO PAY FOR OUR GOOD INTENTIONS. M O R E T O E X P L O R E Who Are We? Indigenous Microbes and the Ecology of Human Diseases. Martin J. Blaster in EMBO Reports, Vol. 7, No. 10, pages 956–960; October 2006. www.ncbi.nlm.nih. gov/pmc/articles/PMC1618379 A Human Gut Microbial Gene Catalogue Established by Metagenomic Sequencing. Junjie Qin et al. in Nature, Vol. 464, pages 59–65; March 4, 2010. Has the Microbiota Played a Critical Role in the Evolution of the Adaptive Immune System? Yun Kyung Lee and Sarkis K. Mazmanian in Science, Vol. 330, pages 1768–1773; December 24, 2010. www.ncbi.nlm.nih.gov/pmc/articles/PMC3159383 SCIENTIFIC AMERICAN ONLINE For an interactive feature about some of the key microbial species found in and on the body, visit ScientificAmerican.com/jun2012/microbiome- graphic
© 2012 Scientific American Title of Assignment Professional Identity of the Nurse: Scope of Nursing Practice Purpose of Assignment: According to Larson, Brady, Engelmann, Perkins, and Shultz (2013), “the development of professional identity is a continuous process that begins with admission to the nursing program and evolves throughout one’s professional career in a dynamic and fluid process where interacting relationship of education and practice lead to self-reflection, growth, and human flourishing” (p. 138). Larson, J., Brady, N., Engelmann, L., Perkins, B., & Shultz, C. (2013). The formation of professional identity in nursing. Nursing Education Perspectives.34 (2). p 138. Course Competency(s): Describe the foundations of nursing practice. Explain the roles and scope of practice for members of the intraprofessional team. Describe principles of effective communication in the healthcare setting. Instructions: This course includes a project with three parts. Each part builds off prior knowledge to help you create your nurse professional identity. In the first part, you examine the role of the nurse and scope of practice, which will help you identify the nurses’ role. In the second part, you describe the importance of the code of ethics in nursing, and examine the standards of nursing practice for the role you are obtaining during the nursing program. The final submission requires you to use the first two parts of your assignment to explain your belief of caring in nursing, describe your professional identity, and identify a potential professional organization that you may join to help support your development.
Content: Prepare a two to three page written assignment that includes the following: · Introduction to the assignment (sections of the assignment) · Describe the importance of the code of ethics in nursing · Identify the American Nurses Association Standards of Practice for the licensure you are obtaining (LPN or RN) · Conclusion (reflect on the criteria of the assignment) · Use at least two credible resources to support your findings. For example, one of the resources could be the ANA Standards of Practice, and another resource could be the ANA Code of Ethics. These resources must be integrated into the body of your paper using at least two in-text citations. Be sure to use proper APA format and style. Format: · Two to three page written assignment · Standard American English (correct grammar, punctuation, etc.) · Logical, original and insightful · Professional organization, style, and mechanics in APA for mat · Run your paper through Grammarly and make corrections to identified errors before submission. Note: You must use the following link to create your Grammarly account. You must use your Rasmussen student email address: https://www.grammarly.com/signin?page=edu Resources: Rasmussen College Online Library School of Nursing > Your Career > Jobs and Outlook > Professional Associations Tab · https://guides.rasmussen.edu/nursing/jobsandoutlook Writing Help Rasmussen College offers many different resources to support your academic writing.
· Writing Help: How do I access writing support? Research Help School of Nursing Online Guide > Nursing Research https://guides.rasmussen.edu/nursing/research Before you begin your search, it is important to understand: · What is a scholarly or peer reviewed article? · What is the difference between evidence-based articles and scholarly, research articles? · How do I know if a source is credible? Use the links below when you are ready to start searching the online library: · How do I find scholarly/peer-reviewed nursing articles? · How do I find articles about nursing best practices? · Discovery database: What is it, and how do I use it? APAHelp New to APA? Watch this video for a brief introduction: · APA Quick Start Want a more in-depth introduction to APA? Watch the 30 minute APA Basics webinar: · APA in 30 Minutes The APA Guide contains all of the information you need to create a research paper in the APA style, including: · APA Sample Paper · APA Paper Template · Examples of Reference list citations · In-text citations · Formatting an APA paper including the cover page Integrating resources into your writing is a crucial writing skill. Watch this video on how to paraphrase, summarize, and quote
resources. · Integrate outside resources into your academic writing Learn more about creating a references list and how NoodleTools can help you by watching the webinar below or view our series of short videos: · APA Reference List and NoodleTools Software · NoodleTools Video Series Grading Rubric: Total Possible Points = 100 Levels of Achievement Criteria Emerging Competence Proficiency Mastery Introduction (10 Pts) Initial introduction does not include explanations of the sections of the paper. Failure to submit introduction will result in zero points for this criteria. Introduction includes a brief explanation for the sections of the paper. Introduction includes a clear explanation of the sections of the paper and supporting evidence. Introduction includes a comprehensive explanation for the sections of the paper with detailed examples and supporting evidence. Points: 6 Points: 8 Points: 9 Points: 10 Code of Ethics (35 Pts)
Code of ethics section lacks suggestions and/or supporting evidence. Failure to submit this section will result in zero points for this criteria. Code of ethics section includes minimal discussion on ethics with limited supporting evidence. Code of ethics section includes discussion with examples and supporting evidence. Code of ethics section offers substantial contributions and detailed examples with supporting evidence. Points: 21 Points: 28 Points: 31 Points: 35 Standards of Practice (35 Pts) Standards of Practice lacks presentation and/or supporting evidence. Failure to submit this section will result in zero points for this criteria. Standards of Practice includes minimal presentation with limited supporting evidence. Standards of Practice includes presentation with examples with supporting evidence. Standards of Practice includes substantial presentation and detailed examples with supporting evidence. Points: 21 Points: 28 Points: 31 Points: 35 Conclusion (10 Pts) Conclusion lacks a summary of the sections of the paper. Failure to submit this section will result in zero points for this
criteria. Conclusion includes minimal summary of the sections of the paper. Conclusion includes a summary of the paper with supporting evidence. Conclusion includes a substantial summary of the paper with detailed examples with supporting evidence. Points: 6 Points: 8 Points: 9 Points: 10 Spelling and Grammar (5 Pts) Spelling and grammar contain substantial errors that make sentences and/or paragraphs incoherent. Spelling and grammar errors occur but are inconsistent. Paragraphs and sentences are coherent but may exhibit spelling errors, run-on’s or fragments, and/or improper verb tense usage. Displays proper grammar application, and writing contains minimal to no spelling errors. May contain rare improper uses of words (ex., their vs. there), a misplaced modifier, or a run-on sentence, but does not detract from the overall understanding of the sentence and/or paragraph. Demonstrates an exemplary application of spelling and grammar. Points: 2 Points: 3 Points: 4
Points: 5 APA Citation (5 Pts) Citations do not follow APA Style. Quotations, paraphrases, and summaries are not cited, or there is no attempt to cite them using APA style. Errors in APA citations are noticeable and may detract from the ability to locate the original source (for example, no title provided, year of publication is missing, no punctuation). Errors in APA citations are less noticeable and do not detract from the ability to locate the original source (for example, a missing or misused comma or period, missing parentheses, author name not properly abbreviated, indentation is misaligned). APA citations are free of style and formatting errors. Points: 2 Points: 3 Points: 4 Points: 5 Nested or Networked? Future Directions for Ecological Systems Theory Jennifer Watling Neal and Zachary P. Neal, Michigan State University Abstract
Bronfenbrenner’s ecological systems theory (EST) is among the most widely adopted theoretical frameworks for studying individuals in ecological contexts. In its traditional formulation, different levels of ecological systems are viewed as nested within one another. In this article, we use Simmel’s notion of intersecting social circles and Bronfenbrenner’s earlier writing on social networks to develop an alternative ‘net- worked’ model that instead views ecological systems as an overlapping arrangement of structures, each directly or indirectly connected to the others by the direct and indirect social interactions of their participants. We redefine each of the systems discussed by EST—micro, meso, exo, macro, and chrono—based on patterns of social interaction, and then illustrate how this alternative model might be applied in the classic context of the developing child. We conclude by discussing future directions for how the networked model of EST can be applied as a conceptual framework, arguing that this approach offers developmental researchers with a more precise and flexible way to think about ecological contexts. We also offer some initial suggestions for moving a networked EST model from theory to method. Keywords: ecological systems theory; social networks; context; Bronfenbrenner Introduction Originally proposed by Bronfenbrenner (1977, 1979), ecological
systems theory (EST) has been widely adopted by developmental psychologists interested in understanding individuals in context. Indeed, Google Scholar reveals that The Ecology of Human Development (Bronfenbrenner, 1979), which first outlined EST, has been cited nearly 15 000 times as of September 2012. Conceptually, EST has been used to motivate a focus on setting-level influences, guiding the development of contextual models to explain a range of phenomena including urban adolescent psychological and academic outcomes (e.g., Seidman, 1991), developmental risk and protective factors for substance use (e.g., Szapocznik & Coatsworth, 1999), youth activity engagement (e.g., Rose-Krasnor, 2009), and family influences on gender development (e.g., McHale, Crouter, & Whiteman, 2003). Empirically, developmental studies have used Correspondence should be addressed to Jennifer Watling Neal, Department of Psychology, 316 W. Physics Road., 127A Psychology Building, Michigan State University, East Lansing, MI 48824, USA. Email: [email protected] Social Development Vol 22 No. 4 722–737 November 2013 doi: 10.1111/sode.12018 © 2013 John Wiley & Sons Ltd EST to identify contextual predictors or points of intervention that lie beyond the
individual. For instance, studies of children and youth have often examined aspects of the peer, family, classroom/school, and neighborhood microsystems (e.g., Chipuer, 2001; Criss, Shaw, Moilanen, Hitchings, & Ingoldsby, 2009; Gest & Rodkin, 2011; Gifford-Smith & Brownell, 2003; Seidman et al., 1995) or mesosystemic interactions between these microsystems (e.g., Durlak et al., 2007; Serpell & Mashburn, 2012). However, in general, empirical exploration of exosystems and macrosystems in devel- opmental studies applying an EST framework remains less frequent. Although EST is widely recognized for underscoring the importance of interdepend- ent and multilevel systems on individual development, the precise relationships of systems to one another remain elusive. Bronfenbrenner (1979) originally described ecological systems at different levels as nested within one another, giving rise to EST’s classic graphic portrayal as a set of concentric circles. However, in this article, we argue that conceptualizing ecological systems as nested obscures the relationships between them. Instead, we argue that ecological systems should be conceptualized as networked, where each system is defined in terms of the social relationships surround- ing a focal individual, and where systems at different levels relate to one another in an overlapping but non-nested way. Defining ecological systems in network terms not only provides greater theoretical clarity but also yields a form
of EST that more closely matches Bronfenbrenner’s (1945) early recognition of the role of social networks in shaping development. To build this argument, we begin by reviewing the traditional conceptualization of ecological systems as nested and highlight recent modifications to the theory. Then, drawing on Simmel’s (1955 [1922]) notion of intersecting social circles, we discuss how ecological systems are better conceptualized as networked rather than nested. We illustrate the networked model of EST using the hypothetical example of a developing child. Finally, we discuss implications of this new conceptualization of ecological systems theory for future research. Ecological Systems as Nested: The Traditional Model Bronfenbrenner first proposed EST in a series of seminal publications in the 1970s and 1980s. We focus on the theory and definitions provided in The Ecology of Human Development (Bronfenbrenner, 1979), which are largely consistent with his earlier and later writing (Bronfenbrenner, 1977, 1986a, 1986b), and which are summarized in Table 1. Bronfenbrenner (1979) described the topology of the ecological environment as ‘a nested arrangement of structures, each contained within the next’, which must be examined as an interdependent whole to fully understand the forces surrounding a developing individual (p. 22). This approach represented a
sharp departure from more traditional approaches to developmental psychology of the day, which he derided as ‘the science of the strange behavior of children in strange situations with strange adults for the briefest possible periods of time’ (p. 19). His initial articulation of EST identified four such structures, or systems—the microsystem, mesosystem, exosystem, and macrosystem—that are nested around a focal individual like a set of concentric circles, or as Bronfenbrenner suggested, a set of Russian dolls (i.e., a matryoshka doll). Thus, nearly all graphical depictions of EST rely on some variation of the concentric circles model shown in Figure 1. Bronfenbrenner (1979) viewed each system as arising from a setting, which he defined as ‘a place where people can readily engage in face-to- face interaction’ Nested or Networked? 723 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 T ab le 1. N
es te d an d N et w or k ed D efi n it io n s of E co lo gi ca
l S ys te m s C on st ru ct s C o n st ru ct N es te d (f ro
m B ro n fe n b re n n er ,1 9 7 9 ) N et w o rk ed E co
lo g ic al E nv ir o n m en t ‘. . . a n es te d ar ra n g em
en t o f st ru ct u re s, ea ch co n ta in ed w it h in th e n ex
t.’ (p . 2 2 ) . . . an ov er la p p in g ar ra n g em en t
o f st ru ct u re s, ea ch d ir ec tl y o r in d ir ec tl y co
n n ec te d to th e o th er s by th e d ir ec t an d in d ir
ec t so ci al in te ra ct io n s o f th ei r p ar ti ci p an ts
. S et ti n g ‘. . . a p la ce w h er e p eo p le ca n re ad
il y en g ag e in fa ce -t o -f ac e in te ra ct io n .’ (p . 2 2 )
. . . a se t o f p eo p le en g ag ed in so ci al in te ra ct io
n , w h ic h n ec es sa ri ly o cc u rs in , an d is li ke ly
af fe ct ed by th e fe at u re s o f, a p la ce . M ic ro sy st
em ‘. . . a p at te rn o f ac ti v it ie s, ro le s, an d in te
rp er so n al re la ti o n s ex p er ie n ce d by th e d ev el o
p in g p er so n in a g iv en se tt in g w it h p ar ti cu la r
p hy si ca l an d m at er ia l ch ar ac te ri st ic s. ’ (p . 2
2 ) . . . a se tt in g — th at is , a se t o f p eo p le en
g ag ed in so ci al in te ra ct io n — th at in cl u d es th e fo
ca l in d iv id u al . M es o sy st em ‘. . . th e in te rr el
at io n s am o n g tw o o r m o re se tt in g s in w h ic h
th e d ev el o p in g p er so n ac ti ve ly p ar ti ci p at es .’
(p . 2 5 ) . . . a so ci al in te ra ct io n b et w ee n p
ar ti ci p an ts in d if fe re n t se tt in g s th at b o th in
cl u d e th e fo ca l in d iv id u al . E x o sy st em ‘. . .
o n e o r m o re se tt in g s th at d o n o t in vo lv e th
e d ev el o p in g p er so n as an ac ti ve p ar ti ci p an t,
b u t in w h ic h ev en ts o cc u r th at af fe ct , o r ar e
af fe ct ed by , w h at h ap p en s in th e se tt in g co n ta
in in g th e d ev el o p in g p er so n .’ (p . 2 5 ) . . .
a se tt in g — th at is , a se t o f p eo p le en g ag ed in so
ci al in te ra ct io n — th at d o es n o t in cl u d e, b u
t w h o se p ar ti ci p an ts in te ra ct d ir ec tl y o r in
d ir ec tl y w it h , th e fo ca l in d iv id u al . M ac ro
sy st em ‘. . . co n si st en ci es , in th e fo rm an d co n te
n t o f lo w er -o rd er sy st em s th at ex is t, o r co u ld
ex is t, at th e le ve l o f su b cu lt u re o r cu lt u re as a
w h o le , al o n g w it h an y b el ie f sy st em s o r id
eo lo g y u n d er ly in g su ch co n si st en ci es .’ (p . 2
6 ) . . . th e so ci al p at te rn s th at g ov er n th e fo
rm at io n an d d is so lu ti o n o f so ci al in te ra ct io n
s b et w ee n in d iv id u al s (e .g ., h o m o p h il y,
tr an si ti v it y, an d so o n ), an d th u s th e re la ti o
n sh ip s am o n g ec o lo g ic al sy st em s. C h ro n o sy st
em ‘. . . th e in fl u en ce o n th e p er so n ’s d ev el o p
m en t o f ch an g es (a n d co n ti n u it ie s) ov er ti m
e in th e en v ir o n m en ts in w h ic h th e p er so n is li
v in g .’ (B ro n fe n b re n n er , 1 9 8 6 b , p . 7
2 4 ) . . . th e o b se rv at io n th at p at te rn s o
f so ci al in te ra ct io n s b et w ee n in d iv id u al s ch
an g e ov er ti m e, an d th at su ch ch an g es im p ac t th e
fo ca l in d iv id u al , b o th d ir ec tl y an d by al te ri
n g th e co n fi g u ra ti o n o f ec o lo g ic al sy st em
s ar o u n d h im /h er . 724 Jennifer Watling Neal and Zachary P. Neal © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 (p. 22). At the lowest level of his nested hierarchy, microsystems are settings where the focal individual plays a direct role, has direct experiences, and has direct social interactions with others. Using the classic example of a developing child (see Figure 1), the family is a microsystem where the child plays a direct role (e.g., daughter, sibling), has direct experiences (e.g., enjoying family meals), and has direct social interactions with others (e.g., reading with mom, teasing baby brother).
Mesosystems, within which microsystems are nested, include social interactions between two of the focal individual’s settings. In our example, a mesosystem could include a meeting between a parent (from the child’s family setting) and teacher (from the child’s school setting) about a child’s classroom behavior. This meeting represents a social interaction between members of the child’s family microsystem and school microsystem. Exosystems, within which mesosystems are nested, include settings that influence the focal individual but in which the focal individual does not directly participate. An individual child generally does play a role in or have direct experiences in the education policy-making community, but educational policies nonetheless influence the child’s classroom and school experiences. For example, a district decision to consolidate schools to save money may lead to larger classroom and school sizes, changing the microsystems in which children interact. Finally, mac- rosystems, within which exosystems are nested, include broad cultural influences or ideologies that have long-ranging consequences for the focal individual. For instance, societal views that place emphasis on teacher accountability and standard- ized test scores have led to policies such as the No Child Left Behind Act of 2001 that have implications for how children experience schooling. In addition to the four core systems of EST, Bronfenbrenner (1986a, 1986b) later introduced the chrono-
system, a system reflecting change or continuity across time that influences each of the other systems. Transitions like a child’s move from middle to high school or the onset of puberty are part of the chronosystem. Microsystem ‘The family’ Mesosystem ‘Parent-teacher’ Exosystem ‘Education policy’ Macrosystem ‘Societal views on education’ Figure 1. Nested Model of Ecological Systems Originally Proposed by Bronfenbren- ner (1979). Nested or Networked? 725 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 Although nesting is a hallmark of EST, many of the systems in EST are simply not nested in nature. In our example of a developing child above, the family microsystem is nested inside the educational policy-making exosystem, but it makes little sense to view the former as a subset of the latter. Instead these are two
distinct systems, arising in distinct settings—one that contains the child and one that does not—that influence one another. Thus, we argue that viewing ecological systems as nested undermines the theoretical coherence and conceptual utility of EST. A focus on social interactions can help clarify how ecological systems are connected. Social interactions are a key component of EST and, perhaps not surprisingly, as Bronfenbrenner (1945) was a pioneer in the earliest days of social network research. Bronfenbrenner (1979) clearly defined both the microsystem and the mesosystem in terms of social interactions. For example, he noted that the analysis of the microsystem ‘must take into account the indirect influence of third parties on the interaction between members of a dyad’ because a focus on dyadic social interactions alone ignores the wider social context and is thus insufficient to capture the social forces bearing on the focal individual (proposition E; p. 68). Similarly, he defined mesosystems as arising from, among other types of interconnections, the ‘intermediate links in a social network’ (p. 25). However, despite its explicit focus on social interactions, applications of EST typically have not focused their attention on patterns of social interactions. For example, Szapocznik and Coatsworth (1999) noted that the examination of mesosys- tems instead typically focuses on the interdependence of functioning across multiple domains in general terms (e.g., the effects of functioning at
home on functioning at school). Thus, they call for a return to the exploration of social interactions that comprise both microsystems and mesosystems. In the current article, we answer this call, and we push it further by presenting not simply these two systems but also the whole of EST through the lens of networks of social interactions. Ecological Systems as Networked: A Social Network Model Although not referenced in his early work on social networks (Bronfenbrenner, 1945) or formal articulation of EST (Bronfenbrenner, 1979), Bronfenbrenner’s theo- retical orientations bear a close resemblance to the work of Georg Simmel (1858– 1918). For example, Bronfenbrenner’s call for ecologically minded psychologists to look beyond the dyad explicitly parallels Simmel’s (1950 [1908]) extensive writing on the differences between dyads and triads, and his contention that socially inter- esting phenomena arise only in settings with more than two actors. Still more directly relevant to our reformulation of EST is Simmel’s (1955 [1922]) essay on social circles, which closely resemble what Bronfenbrenner called systems. Simmel recognized that when circles/systems are concentrically arranged, ‘participation in the smallest of these . . . already implies participation in the larger’ (p. 147), and thus that the forces impacting a person’s development are entirely determined by the
smallest circle/system in which he or she participates. Simmel and other early social theorists (e.g., Durkheim 1984 [1893]; McPherson 2004) viewed such an arrange- ment of social circles as the hallmark of a ‘primitive’ society with a relatively undif- ferentiated social structure. For example, in feudal society governed by tradition and custom, membership in a particular family determined one’s trade, and one’s trade determined one’s friends (i.e., other guild members) and one’s place of residence. Thus, family membership—the smallest social circle/system— fully determined the ecological forces impacting one’s development. 726 Jennifer Watling Neal and Zachary P. Neal © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 In contrast, Simmel hypothesized that the range of forces impacting a person’s development ‘will be greater when the [circles] which influence him are juxtaposed than if they are concentric’ (p. 147). Bronfenbrenner offered the same hypothesis more than 50 years later, noting that ‘the developmental status of the individual is reflected in the substantive variety and structural complexity of the . . . activities which she initiates’ (Bronfenbrenner, 1979, p. 55). Clearly, both Simmel and Bronfenbrenner appreciated that the ecological influences brought to bear on
individuals are far more complex than a simple nested/concentric configuration of social circles/systems could adequately capture. However, simply redrawing the traditional graphic representation of EST using intersecting, rather than nested or concentric, circles does little to clarify the underlying theoretical model. For this job, we turn to social networks and the importance of patterns of social interaction, with which both Simmel and Bronfen- brenner were intimately familiar. The fundamental building block of EST is the setting; thus, any attempt to re-theorize EST must begin here. For Bronfenbrenner (1979), ‘a setting is a place where people can readily engage in face-to-face interaction’ (p. 22, emphasis added), and thus it has a primary spatial dimension and a secondary interactional dimension. However, when it comes to forces that influence individuals’ development, are inter- actional factors really secondary to spatial ones? Compare the developmental conse- quences of couple A interacting lovingly at home, and couple B interacting lovingly on vacation. A social network, or structuralist, perspective contends that common forces are likely to shape the development of these two couples because they are engaged in common patterns of interaction, even if in different locations. Similarly, compare the developmental consequences of couple A interacting lovingly at home, and couple C fighting at home. Here, a network perspective contends that
different forces are likely to shape the development of these two couple because they are engaged in different patterns of social interaction, even if in the same location. Thus, although we continue to view settings as the fundamental building block of EST, adopting a network per- spective, we offer a definition that mirrors but inverts Bronfenbrenner’s by focusing primary attention of patterns of social interaction: a setting is a set of people engaged in social interaction, which necessarily occurs in, and is likely affected by the features of, a place (see Table 1). This focus on patterns of social interaction has previously been advocated in the specific context of EST by Szapocznik and Coatsworth (1999), more generally in community psychology by Seidman (1988), and across the social sciences since the initial sociometric work of Moreno (1934). Notably, although our conception of a setting places primary attention on the patterns of social interaction, it does not reject that spatial factors may nonetheless play an important role. Having defined settings as sets of interacting people, we begin our networked reformulation of EST by observing that the ecological environment is an overlapping arrangement of structures, each directly or indirectly connected to the others by the direct and indirect social interactions of their participants. This definition not only highlights that systems are not necessarily nested within one another but also clarifies
that it is individuals’ patterns of social interactions with other another that determine how systems relate to one another. Moreover, it allows each type of system to be precisely defined in terms of patterns of interaction. Figure 2 illustrates a hypothetical pattern of social interactions—that is, a social network—among nine people (labeled A thru I), with the focal individual represented by the shaded circle in the center. Each set of people who all interact with one another—that is, a setting—is enclosed by a dashed circle. For example, persons A thru Nested or Networked? 727 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 D all interact with one another and thus constitute a setting. From these settings, it is possible to identify ecological systems using definitions that closely parallel those originally proposed by Bronfenbrenner. First, a microsystem is a setting—or set of people engaged in social interaction—that includes the focal individual. In this example, there are three microsystems: one on the left composed of A–B–C–D, one on the right composed of A–E–F–G, and one that overlaps with these two composed of A–D–E. Second, a mesosystem is a social interaction between participants in different
settings that both include the focal individual. Here, the relationship between D, who participates in the setting on the left, and E, who partici pates in the setting on the right, is a mesosystemic interaction. Finally, an exosystem is a setting—or set of people engaged in social interaction—that does not include, but whose participants interact directly or indirectly with, the focal individual. This example contains one setting, composed of G–H–I, that is an exosystem. Together, these individuals constitute an interactional setting that does not contain the focal individual, but whose participants are each directly (e.g., person G) or indirectly (e.g., persons H and I, by two steps) connected to the focal individual. As the simple example in Figure 2 illustrates, adopting this approach highlights the intersecting, non-nested character of ecological systems. For example, different microsystems can overlap when they involve distinct sets of individuals participating in different settings. Similarly, the mesosystem is ipso facto a social interaction that requires the intersection of two microsystems. However, by more robustly specifying the relationships between systems at different ecological levels, the networked model of EST also expands the utility of the theory by making it possible to consider the ecological environment from the perspective of different focal individuals. Suppose the simple social network shown in Figure 2 represented the entire social universe. If
person A is the focal individual, as the figure illustrates, this person’s development is influenced by three microsystems, one mesosystem, and one exosystem. However, applying the same network-based definitions of ecological systems, it is possible to consider what systems shape the development of, for example, person C instead. In contrast to person A, person C’s development is influenced by one microsystem (A–B–C–D), no mesosystems, and three exosystems (A–D–E, A–E–G–F and G–H–I). This highlights that the specific nature and configuration of ecological systems Microsystem Exosystem Microsystem A B C D E F G HI Microsystem
Mesosystemic interaction Figure 2. Networked Model of Ecological Systems, Focused on Person A. 728 Jennifer Watling Neal and Zachary P. Neal © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 influencing the development of an individual depends on, must be considered from, the perspective of the focal individual. Although A–E–G–F is a microsystem for person A, it is an exosystem for person C. To this point, we have considered only the first three of EST’s five systems. The macrosystem and chronosystem are not built from settings, but rather refer to forces that shape the patterns of social interactions that define settings. First, the macrosystem is the set of social patterns that govern the formation and dissolution of social interactions between individuals, and thus the relationship among ecological systems. For example, the social pattern known as homophily refers to individuals’ tendency to interact with others who share a social status (e.g., race, gender, and so on) or who share an attitude or value orientation (e.g., commitment to social justice) (Lazarsfeld &
Merton, 1964; McPherson, Smith-Lovin, & Cook, 2001). Similarly, transitivity refers to the tendency for two individuals with a common acquaintance to interact as they are brought together in common settings, by common values, or with common goals (Feld, 1981). As enduring patterns in human social interaction, homophily and transitivity significantly determine the structure of social networks, and thus the configuration of ecological systems surrounding a focal individual. In addition to structural tendencies like homophily and transitivity, broad forces like legal, political, and cultural systems typically associated with the macrosystem also manifest their effects in the structure of social networks by shaping with whom one may, or is likely to, interact. Second, the chronosystem is the observation that patterns of social interactions between individu- als change over time, and that such changes impact the focal individual, both directly and by altering the configuration of ecological systems surrounding him/her. The modeling and analysis of dynamic social networks is an emerging area of study, with some seeking to understand how networks evolve endogenously (Robins, Pattison, Kalish, & Lusher, 2007), and others exploring how both natural (e.g., social develop- ment; Schaefer, Light, Fabes, Hanish, & Martin, 2010; Veenstra & Dijkstra, 2011) and intentional (e.g., interventions; Hawe, Shiell, & Riley, 2009) exogenous forces can modify network structures.
A Hypothetical Example To concretely illustrate ecological systems as networked, in this section, we return to the classic example of a developing child used in Bronfenbrenner’s (1977, 1979, 1986a, 1986b) original formulation of EST. As noted earlier, EST has traditionally viewed the child as positioned at the center of a series of nested ecological systems leading from those most immediate to the child (e.g., microsystems such as the family and school) to those most distal (e.g., macrosystemic forces such as societal views on education) (see Figure 1). However, conceptualizing EST in terms of social networks leads to a strikingly different arrangement of the ecological systems surrounding the child. Following Simmel’s (1955 [1922]) conception of social circles, the child appears as part of an overlapping or intersecting set of ecological systems that are linked to one another through direct and indirect social interactions (see Figure 3). In Figure 3, the focal child in our example participates in two different settings. The setting on the left, composed of the daily familial interactions of the child, mother, father, and sibling can be identified as a microsystem because the focal individual (i.e., the child) is a participant. Moreover, it can be identified specifically as a family microsystem given the specific identities and roles of its participants and the content of their social interactions. The setting on the right, composed of
the social interactions Nested or Networked? 729 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 between the child, teacher, coach, and principal can also be identified as a microsystem, again because the child is a participant, and more narrowly as a school microsystem given the identities and roles of its participants and the content of their social interac- tions. Both the family and the school settings have long been recognized as key microsystems impacting the children’s development. For example, researchers have studied social processes within the family including social support, hassles, parent– child relationships, and sibling relationships (e.g., Bokhorst, Sumter, & Westenberg, 2010; Bronfenbrenner, 1986a; McHale et al., 2003; Seidman et al., 1995). Similarly, they have also examined social processes within schools including teacher–student relationships (e.g., Hamre, Pianta, Downer, & Mashburn, 2008; Howes, 2000; Pianta, 1999; Troop-Gordon & Kopp, 2011), teacher practices (e.g., Cappella & Neal, 2012; Gest & Rodkin, 2011), school social support (e.g., Bokhorst, Sumter, & Westenberg, 2010; Seidman et al., 1995), and peer interactions (see Gifford- Smith & Brownell, 2003 for review). However, although previous research has
typically defined the boundaries and participants of microsystems in advance, a networked model of EST relies on the actual social interactions within the child’s life to locate them. This approach, focusing on actual patterns of social interaction rather than a priori expec- tations, mirrors Wellman’s (1988) recommendation that the social world be viewed as ‘composed of networks, not groups’ (p. 37). One social interaction, between the child’s mother and the teacher, bridges between these two microsystems. Because this social interaction occurs between participants in different settings that both include the focal individual, it can be identified as a mesosystem. More specifically, given the context of this cross - setting social interaction in our example, we identify it as a school/family mesosystem. Such family–school relationships may occur when parents or guardians meet with teachers at school conferences, volunteer in the classroom, or receive regular notes from teachers about their child’s progress, and are a main focus in educational practice and research (e.g., Epstein, 1995; Kelley, 1990; Serpell & Mashburn, 2012). In our example, perhaps the child’s mother regularly speaks with the teacher over the phone about her daughter’s MayorSuperintendent CHILD
Father Principal TeacherMother Sibling Coach The Family Microsystem The School Microsystem The Education Policy Exosystem The School/Family Mesosystemic Interaction Figure 3. Hypothetical Example Illustrating a Networked Model of Ecological Systems 730 Jennifer Watling Neal and Zachary P. Neal © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 progress in class and has been able to build a relationship with the teacher through this experience. Defining the mesosystem as a relationship that bridges two microsystems allows researchers to study direct social interactions, which have been described as an ‘understudied phenomenon’ in assessments of the
mesosystem (Szapocznik & Coatsworth, 1999, p. 346). Figure 3 also contains a setting—that is, a set of people engaged in social interaction—that does not include the child. This setting, located in the upper right corner, is composed of the social interactions among three actors in the educational policy area: the superintendent, mayor, and principal. Because the child does not actually participate in this setting, but nonetheless directly or indirectly interacts with its participants—here, directly with the principal, and indirectly with the superintend- ent and mayor via the principal—the setting can be identified as an exosystem. More specifically, given the roles of this setting’s participants and the content of their social interactions, we identify it as the education policy exosystem. The role of school administrators, government officials, and policy-makers in indirectly shaping chil- dren’s development has often been explored in educational research (e.g., Daly & Finnigan, 2010; Spillane & Thompson, 1997). For example, the mayor may start a healthy eating campaign in the city and may work with the superintendent and prin- cipal to eliminate unhealthy foods in the school cafeteria. These cafeteria changes will impact on the focal child’s school microsystem, and it may lead her to choose healthier options like fruits or vegetables at lunchtime. However, the focal child is only indirectly connected to the setting responsible for these changes.
The configuration of the microsystems, mesosystem, and exosystem as intersecting in the networked model of EST illustrated by Figure 3 is notably different from their configuration as nested in the more traditional model of EST illustrated by Figure 1. For example, the traditional model of EST views microsystems as nested within mesosystems. However, it makes little sense to suggest that the family or school settings are nested within the mother–teacher relationship. To be sure, the family and school microsystems are affected by the mother–teacher relationship, but they are not inside of it. Instead, as the networked model highlights, mesosystemic interactions like those between a mother and teacher can more properly be understood as existing between intersecting microsystems. Similarly, the traditional model views the meso- system as nested within the exosystem. Again, it makes little sense to suggest that the mother–teacher relationship is nested within the education policy system. In fact, in our example, none of the participants in the mesosystem (i.e., the mother and teacher) are participants in the exosystem (i.e., the principal, superintendent, and mayor). The networked model of EST highlights that mesosystems and exosystems are distinctly different types of settings that could, but are not required to, overlap. Viewing eco- logical systems as a series of settings that intersect and overlap to varying degrees, as the networked model does, provides EST greater flexibility by
not rigidly specifying that each system is wholly nested within the next, and also allows understandings about the relationships between different systems to more closely mirror reality. Although Figure 3 does not include an overt illustration of the macrosystem or chronosystem, a networked model of these two systems can still be applied to the developing child in our example. Identification of macrosystemic factors that influence the focal child involves considering the social patterns that influence the formation and dissolution of social interactions between individuals in the child’s social world. For example, examining Figure 3, the social pattern of homophily might be useful for explaining the mesosystemic relationship between the child’s mother and the Nested or Networked? 731 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 classroom teacher. Perhaps the mother and teacher are connected because they share a viewpoint—for example, that education is important—which leads to their increased social interaction and a strengthened relationship between them. Similarly, the social pattern of transitivity might help explain the relationship between the school principal
and the mayor in the educational policy exosystem. The superintendent’s job is likely to require social interaction with both the principal and the mayor. Because both the principal and the mayor interact regularly with the superintendent, transitivity suggests that social interaction is likely to occur directly between the principal and the mayor as well, perhaps through joint meetings to discuss the implementation of a healthy foods initiative. The macrosystem is frequently associated with legal, political, and cultural phenom- ena, which may appear lacking in this networked perspective. However, because such macrosocial phenomena directly impact how individuals interact with one another, the networked perspective does not exclude their consideration. Several examples serve to illustrate. Firstly, consider the effect of a legal ruling requiring school desegregation (e.g., Brown v. Board of Education). Because such a ruling will alter the demographic composition of schools, it will directly impact the level of diversity of the focal child’s network. Secondly, consider the effect of a shift in the political structure of the school board, from one constituted by appointment to one constituted by democratic election. Such a shift may require members of the education policy exosystem to expand their networks in search of electoral support, thereby potentially altering the size of the exosystem and its relationship to the other systems. Finally, consider the effect of
cultural practices surrounding gender, and specifically the difference between a culture that favors gender-separate education and one that favors coeducational institutions. Such a cultural value will directly impact the potential and actual gender homophily observed in the focal child’s network. The networked model of EST may be unable to capture all possible macrosocial phenomena, but likely no model could rise to this task. However, it can capture macrosocial phenomena to the extent that their effects are reflected in patterns of individuals’ social interactions. We believe that this is sufficient because macrosocial phenomena that do not affect individual s’ social interactions are not likely to have significant or observable impacts on individual development. The chronosystem reflects changes in patterns of social interaction over time and can also be applied to our hypothetical example of the developing child. Life transitions may shape and restructure the social interactions in the focal child’s life. As the focal child’s own patterns of social interaction change, and as the patterns of social inter- action of those indirectly connected to the focal chil d change, the location and rela- tionship of the ecological systems surrounding the focal child will shift. For example, at present, the focal child’s sibling is still a toddler and has not yet started attending school. However, within the next few years, he will start kindergarten in the same school as his sister, potentially leading to new mesosystemic
interactions that bring the school and family microsystems closer together. Moreover, consistent with develop- mental research (e.g., Berndt, 1982; Larson, Richards, Moneta, Holmbeck, & Duckett, 1996), as our focal child moves into adolescence, she may spend less time interacting family members and more time interacting with peers at school or in the neighborhood, shifting relationships within, or even prompting the formation of new, microsystems. Finally, Figure 3 clearly illustrates how the specific nature and configuration of ecological systems influencing the development of an individual must be considered from the perspective of that individual. The focal child described in this example is shaped by a family microsystem, a school microsystem, a school–family mesosystem, 732 Jennifer Watling Neal and Zachary P. Neal © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 and an education policy exosystem. However, considering the social world outlined in Figure 3 from her sibling’s perspective leads to a different configuration. Although the sibling is part of the same family microsystem as his sister, he is still a toddler and is not currently enrolled in school. Thus, from his perspective, the school and the
educational policy settings are both exosystems, to which he is indirectly connected through his sister. He does not directly participate in either the school or educational policy settings, but may still be influenced by his sister to eat his fruits and vegetables due to healthy eating habits that she picked up from her school’s new cafeteria policy. Future Directions for the Networked Model of EST In this article, we have argued that the ecological systems outlined in EST are more usefully conceptualized as networked rather than nested. In contrast to EST’s tradi- tional view of ecological systems as concentrically arranged in a nested configuration, a networked model of EST views ecological systems as overlapping and connected through direct and indirect social interactions. As a conceptual model of the forces impacting individuals’ development, the networked approach offers a number of advantages. Firstly, it shifts the focus of attention away from where individuals interact and toward how and with whom they interact, which is essential to the extent that human development is a social process. Secondly, it allows researchers to examine more complex relationships among ecological systems, including a multiplicity of different microsystems that only partially overlap, and mesosystems and exosystems that bridge these microsystems. Thirdly, it offers a way to more fully incorporate Bronfenbrenner’s (1979) ‘recognition that environmental events
and conditions outside any immediate setting containing the person can have a profound influence on behavior and development’ (p. 18, emphasis added). Although many applications of EST focus primarily on the microsystem, it is not for researchers’ lack of interest in higher order systems but rather for the daunting ambiguity of these systems. The networked model provides more theoretically consistent definitions that clearly specify not only what each system of composed of but also how each system is related to the others. Finally, by more explicitly incorporating social networks into EST, it offers a path for moving from theory to method. From Theory to Method As a theory, EST only specifies constructs, but it does not necessarily specify how those constructs should be empirically operationalized in practice. Thus, both the traditional nested model and our proposed networked model rely on the construct of ‘settings’ as the fundamental building block of ecological systems, but neither model offers a precise empirical operationalization. However, by focusing attention of pat- terns of social interaction, the networked model offers the possibility of using the precise tools of social network analysis to move EST from a theory to a method. A complete discussion and formal validation of network analytic operationalizations of the setting construct would go beyond the scope of this article,
but we briefly consider some possibilities that may be useful in the future translation of our theoretical reformulation of EST into a measurement methodology. We have defined a setting as a set of people engaged in social interaction. Although such a broad definition is appropriate for a theoretical construct, it is too ambiguous for an empirical operationalization, leaving open questions about the necessary amount of Nested or Networked? 733 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 social interaction and the delineation of members from non- members. However, the social network concept of a clique offers some precise answers to such questions, and thus some potential operational definitions of a setting. Moreover, just as settings come in many forms—some are small and intimate whereas others are large and fluid—the network concept of clique has multiple operational definitions. Figure 4 illustrates some conceptions of a network clique that may be useful for operationalizing the construct of settings in EST. The simplest and most restrictive, the maximal complete subgraph, defines a clique as a set of people in which every member directly interacts with every other member (Scott, 2000; Wasserman & Faust,
1994). In Figure 4, there are three examples of a maximal complete subgraph: A–B–C, D–E–F and X–Y–Z. This is implicitly the operationalization of setting we have used in the examples discussed above. However, in practice, this conception of a clique might be most appropriate for defining a small setting, such as a family, where all members are likely to directly interact with one another whereas more inclusive conceptions may be necessary for operationalizing larger settings. An N-clique is a set of people in which every member is no more than N steps away from every other member, and thus in which members interact with one another either directly or indirectly through just a few intermediaries (Scott, 2000; Wasserman & Faust, 1994). This conception might be appropriate for settings larger than a family, but still sufficiently compact that all participants interact at least indirectly with one another, such as a school classroom or an office workplace. Finally, a K-core is a subset of people in which every member is directly connected to at least K other members, and thus in which members interact with some minimum number of other members A B C D
E F Q X Y Z A B C D E F Q X Y Z A B C D
E F Q X Y Z All Maximal Complete Subgraphs Selected 2-Cliques All 2-Cores Figure 4. Types of Network Cliques. 734 Jennifer Watling Neal and Zachary P. Neal © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 (Scott, 2000; Wasserman & Faust, 1994). This conception is the most inclusive and thus might be appropriate for very large settings in which most participants do not directly interact with one another, but where social interaction with just a few others is sufficient for a sense of belonging, such as a school district or political party.
Using network cliques to define settings is not a panacea for dealing with the complexity of ecological environments. Such an approach still requires researchers to consider several questions, including which conception of a clique is appropriate in a given context, and under what circumstances a network clique can be interpreted as a setting. However, for the goal of pushing EST from a purely conceptual model toward a robust method, we believe that these are the right questions for researchers to be asking. When seeking to understand the content and organization of the ecological environment surrounding a developing person, they focus attention on directly meas- urable features of the environment and allow ecological systems to emerge from the data rather than to be defined in advance based on a priori assumptions. Additionally, these questions highlight a path for the future development of EST as a method by suggesting parallels between the concept of an ecological environment and the vast empirical literature on clique analysis (e.g., Everett & Borgatti, 1998) and community detection (e.g., Fortunato, 2010). Summary and Conclusions In this article, we have sought to revisit Bronfenbrenner’s (1979) ecological systems theory, which is perhaps one of the most influential theories guiding developmental research. We contend that although EST is traditionally described using a nested
systems metaphor, it is more usefully viewed as an overlapping configuration of interconnected ecological systems. Thus, we present an alternative ‘networked’ model of EST that defines ecological systems in terms of patterns of social interaction. This approach brings the relational perspective present in Bronfenbrenner’s (1945) earliest writing to EST and offers many benefits. Firstly, it reconceptualizes settings, drawing attention to social interactions as the building blocks of ecological systems. Secondly, it clarifies how ecological systems are related to one another, highlighting that they are not necessarily nested, but instead overlap in complex ways. Finally, it establishes the potential for a direct linkage between EST as a theory and social network analysis as a method, thereby paving the way for more precise operationalization and measure- ment for research adopting an EST perspective, but also for more theoretically informed applications of network analysis. As a new conceptual framework for under- standing what ecological systems are and how they relate to one another, we hope that the networked model of EST offers developmental researchers and others a useful way to think about ecological environments, and that this article represents merely an initial step in its further development. References Berndt, T. (1982). The features and effects of friendship in early adolescence. Child Develop-
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Spillane, J. P., & Thompson, C. L. (1997). Reconstructing conceptions of local capacity: The local education agency’s capacity for ambitious instructional reform. Educational Evaluation and Policy Analysis, 19, 185–203. Szapocznik, J., & Coatsworth, J. D. (1999). An ecodevelopmental framework for organizing the influences on drug abuse: A developmental model of risk and protection. In D. Meyer, & C. R. Hartel (Eds.), Drug abuse: Origins and interventions (pp. 331–366). Washington, DC: American Psychological Association. Troop-Gordon, W., & Kopp, J. (2011). Teacher-child relationship quality and children’s peer victimization and aggressive behavior in late childhood. Social Development, 20, 536–561. doi: 10.1111/j.1467-9507.2011.00604.x Veenstra, R., & Dijkstra, J. K. (2011). Transformations in adolescent peer networks. In B. Laursen, & W. A. Collins (Eds.), Relationship pathways: From adolescence to young adult- hood (pp. 135–154). New York: Sage. Wasserman, S., & Faust, K. (1994). Social network analysis: Methods and applications. New York: Cambridge University Press. Wellman, B. (1988). Structural analysis: From method and metaphor to theory and substance. In B. Wellman, & S. D. Berkowitz (Eds.), Social structures: A network approach (pp. 19–61). New York: Cambridge University Press.
Author Note Jennifer Watling Neal, Department of Psychology, Michigan State University; Zachary Neal, Department of Sociology, Michigan State University. The authors contributed equally in the conceptualization and writing of this article. Nested or Networked? 737 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 INSTRUCTIONS FOR MODULE 5 DISCUSSION AND REFLECTION JOURNAL ESSAYS - ARE YOU READY? FOR MODULE 5 ESSAYS, WRITE ANSWERS TO THE DISCUSSION ESSAY PROMPT BELOW (500 WORDS) AND AN ANSWER TO THE REFLECTION JOURNAL ESSAY PROMPT BELOW (300 WORDS) 1) Propose a culturally and socially appropriate program for diversifying the microbiomes of children who attend pre- schools in Tempe or in a city of your choice (500 words). 2) WHAT'S INTERESTING in this module?Materials and Readings Read the following in preparation for the study questions assignment: · Learning Objective #1 Reading Assignment (attached) (attached) Learning Objectives of Module 5 By the end of this module, students will be able to: 1. Describe Bronfenbrenne's model of nested/networked
relationships between ecology, environment and [biological] child development. 2. Describe the human microbiome. 3. Explain why microbiomes are the most important link between ecological, environmental, sociocultural factors and the biology of the self.Overview In this module, we will explore how goods for health become an integral part of the biology of individuals. We will learn about models of levels of interactions between systems that together form the ecology of an individual. Social interactions are the 'interactions' that matter most in humans since from birth to death, everything we do happens in the context of negotiating, reciprocating, giving or receiving goods and services between individuals.' In this module we will also learn about that social interactions at all ages are part and parcel of the microbial communities that reside in and on our bodies. We have learned a great deal in recent years about reciprocation between humans and our microbial friends, especially bacteria. In our gut, communities of bacteria supplement or altogether take over all sorts of biological functions that influence our metabolic, endocrinological and immune systems. The health of our microbiomes dictates the quality of our lives. When our microbiomes are disrupted by antibiotics, highly processed foods, lack of sleep, drug use, exposure to chemicals and other factors, their ability to perform functions that keep us healthy is compromised. It now appears that in developed countries with vast expanses of impervious surfaces, gut microbiomes are far less diverse than is the case in small scale societies that live in natural ecosystems with minimal built environments. These populations don't have epidemics of non-communicable diseases. Over 20 years of fieldwork among remote indigenous peoples of Latin America, I did not see a single case of asthma, allergies, breast cancer, Type 1 or Type 2 diabetes, Irritable Bowel Disease, Crohn's Disease or Cardiovascular Disease. Many other
anthropologists who work in small scale societies have made similar observations. In the learning materials you will watch a presentation by Dr. Robert Knight that summarizes major research findings in recent studies of the microbiome. He suggests that the root cause of the co-occurring epidemics of non-communicable diseases over the past 30 years is a sudden change in gut microbiomes. This is an interesting hypothesis, and one of the most important take aways of this course.

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© 2012 Scientific AmericanIllustrations by Bryan Chris

  • 1. © 2012 Scientific American Illustrations by Bryan Christie M E D I C I N E THE ULTIMATE SOCIAL NETWORK Researchers who study the friendly bacteria that live inside all of us are starting to sort out who is in charge—microbes or people? By Jennifer Ackerman June 2012, ScientificAmerican.com 37 © 2012 Scientific American © 2012 Scientific American 38 Scientific American, June 2012 Over the past 10 years or so, however, researchers have demonstrated that the human body is not such a neatly self- sufficient island after all. It is more like a complex ecosystem— a social network—containing trillions of bacteria and other mi-
  • 2. croorganisms that inhabit our skin, genital areas, mouth and especially intestines. In fact, most of the cells in the human body are not human at all. Bacterial cells in the human body outnumber human cells 10 to one. Moreover, this mixed com- munity of microbial cells and the genes they contain, collective- ly known as the microbiome, does not threaten us but offers vi- tal help with basic physiological processes—from digestion to growth to self-defense. So much for human autonomy. Biologists have made good progress characterizing the most prevalent species of microbes in the body. More recently, they have begun to identify the specific effects of these residents. In so doing, they are gaining a new view of how our bodies func- tion and why certain modern diseases, such as obesity and au- toimmune disorders, are on the rise. OUT OF MANY, ONE when people think of microbes in the body, they usually think of pathogens. Indeed, for a long time researchers focused solely on these harmful bugs and ignored the possible importance of more benign ones. The reason, argues biologist Sarkis K. Mazmanian of the California Institute of Technology, is our skewed view of the world. “Our narcissism held us back; we tended to think we had all the func- tions required for our health,” he says. “But just because microbes are foreign, just because we acquire them through- out life, doesn’t mean they’re any less a fundamental part of us.” Indeed, all humans have a microbi- ome from very early in life, even though they do not start out
  • 3. with one. Each individual acquires his or her own community of commensals (from the Latin for “sharing a table”) from the sur- rounding environment. Because the womb does not normally contain bacteria, newborns begin life as sterile, singular beings. But as they pass through the birth canal, they pick up some of Mom’s commensal cells, which then begin to multiply. Breast- feeding and handling by proud parents, grandparents, siblings, and friends—not to mention ordinary contact with bedsheets, blankets, and even pets—quickly contribute to an expanding ark of microbes. By late infancy our bodies support one of the most complex microbial ecosystems on the planet. For the past five years or so scientists have been working to characterize the nature of this ecosystem. The task has been dev- ilishly difficult. The bacterial cells in the intestines, for example, have evolved to grow in the crowded, oxygen-free environment of the gut, so many species do not survive well in the lonely ex- panse of a petri dish. Researchers have gotten around this prob- lem, however, by studying the genetic instructions, the strands of DNA and RNA, found within a microbe rather than the whole cell itself. Because DNA and RNA can be manipulated in a nor- mal, oxygenated laboratory environment, investigators can take microbial samples from the body, extract the genomic material and analyze the results. Each species of commensal bacteria has a signature, it turns out—its own unique version of a gene (known as the 16S ribo- B iologists once thought that human beings were phys iological islands, entirely capable of regulating their own internal workings. Our bodies made all the enzymes needed for breaking down food and using its
  • 4. nutrients to power and repair our tissues and organs. Signals from our own tissues dictated body states such as hun- ger or satiety. The specialized cells of our immune system taught themselves how to recognize and attack dangerous microbes— pathogens—while at the same time sparing our own tissues. Jennifer Ackerman is an award-winning science writer and author of Ah-Choo! The Uncommon Life of Your Common Cold (Twelve, 2010). She is now writing a book about the intelligence of birds. I N B R I E F Bacterial cells in the body outnumber human cells by a factor of 10 to 1. Yet only recently have researchers begun to elucidate the beneficial roles these microbes play in fostering health. Some of these bacteria possess genes that encode for beneficial compounds that the body cannot make on its own. Other bacteria seem to train the body not to overreact to outside threats. Advances in computing and gene se- quencing are allowing investigators to create a detailed catalogue of all the bacterial genes that make up this so- called microbiome. Unfortunately, the inadvertent de- struction of beneficial microbes by the
  • 5. use of antibiotics, among other things, may be leading to an increase in auto- immune disorders and obesity. SO U RC E: E LI N O R AC KE RM A N © 2012 Scientific American June 2012, ScientificAmerican.com 39 somal RNA gene) that codes for a particular RNA molecule found in the ribosomes, the protein-making machinery of cells. By determining the sequence of this gene, scientists are creating a catalogue of the entire human microbiome. In this way, they can glean which species exist in our bodies and how the precise
  • 6. combination of species may differ from one person to another. The next step is to analyze other genes found in the microbial community to determine which ones are active in people and what functions they perform. Again, that chore is a tall order be- cause of the great number of species and because their genes get mixed together in the extraction process. Determining whether a specific bacterial gene is active (or expressed) in the body is rela- tively straightforward; figuring out to which species that partic- ular gene belongs is not. Fortunately, the development of ever more powerful computers and ultrafast gene sequencers in the first decade of the 21st century has turned what would once have been an impossible task of sorting and analysis into merely a very complicated one. Two separate groups of scientists, one in the U.S. and the other in Europe, have harnessed this new technology to enu- merate the bacterial genes within the human body. In early 2010 the European group published its census of microbial genes in the human digestive system—3.3 million genes (from more than 1,000 species)—about 150 times the 20,000 to 25,000 genes in the human genome. Research into the nature of the human microbiome has yielded many surprises: no two people share the same microbial makeup, for instance—even identical twins. This finding may help unravel a mystery presented by the Human Genome Proj- ect, which confirmed that the human DNA of all people the world over is 99.9 percent alike. Our individual fates, health and perhaps even some of our actions may have much more to do with the variation in the genes found in our microbiome than in our own genes. And
  • 7. although the microbiomes of different people vary markedly in the relative number and types of species they contain, most people share a core complement of helpful bacterial genes, which may derive from different spe- cies. Even the most beneficial bacteria can cause serious illness, however, if they wind up somewhere they are not supposed to be—for example, in the blood (causing sepsis) or in the web of tissue between the abdominal or- gans (causing peritonitis). FRIENDS WITH BENEFITS the first inkling that beneficial bugs might do us good came decades ago during research on digestion and the production of vitamins in the guts of animals. By the 1980s investiga- tors had learned that human tissue needs vi- tamin B 12 for, among other things, cellular en- ergy production, DNA synthesis and the man- ufacture of fatty acids and had determined that only bacteria synthesize the enzymes needed to make the vitamin from scratch. Similarly, scientists have known for years that gut bacteria break down certain components of food that would otherwise be indigestible and would pass out of the body un- used. Only in the past few years, however, have they learned the juicy details: two commensal species in particular play major roles in both digestion and the regulation of appetite. Perhaps the prime example of a helpful bug sounds like it
  • 8. was named after a Greek sorority or fraternity. Bacteroides the- taiotaomicron is a champion carbohydrate chomper, capable of breaking down the large, complex carbohydrates found in many plant foods into glucose and other small, simple, easily digest- ible sugars. The human genome lacks most of the genes re- quired to make the enzymes that degrade these complex carbo- hydrates. B. thetaiotaomicron, on the other hand, has genes that code for more than 260 enzymes capable of digesting plant mat- ter, thus providing humans with a way to efficiently extract nu- trients from oranges, apples, potatoes and wheat germ, among other foods. Fascinating details about how B. thetaiotaomicron interacts with, and provides sustenance to, its hosts come from studies of mice raised in a completely sterile environment (so they had no microbiome) and then exposed only to this particular strain of microbes. In 2005 researchers at Washington University in St. Louis reported that B. thetaiotaomicron survives by consuming complex carbohydrates known as polysaccharides. The bacteria ferment these substances, generating short-chain fatty acids (es- sentially their feces) that the mice can use as fuel. In this way, bacteria salvage calories from normally indigestible forms of carbohydrate, such as the dietary fiber in oat bran. (Indeed, ro- dents that are completely devoid of bacteria have to eat 30 per - M O R E T H A N H U M A N Buddy, Can You Spare a Gene? Helping hands: The number of genes distributed among the friendly bacteria that live inside people’s bodies and on their skin far outnumbers the number of genes we inherit from our parents. Researchers are figuring out in greater detail which of these microbial genes benefit their human hosts and how.
  • 9. Human: 20,000 –25,000 genes Gut microbiome: 3.3 million genes © 2012 Scientific American 40 Scientific American, June 2012 Mouth, Pharynx, Respiratory SystemStreptococcus viridans Candida albicans Neisseria sicca Streptococcus salivarius Stomach Bacteroides fragilis Streptococcus thermophilus Helicobacter pylori Lactobacillus
  • 10. casei Lactobacillus gasseri Lactobacillus reuteri Bacteroides thetaiotaomicron Escherichia coli Intestines Urogenital tract © 2012 Scientific American June 2012, ScientificAmerican.com 41 M I C R O B I A L L O C A T O R M A P O F T H E B O D Y Different Species for Different Reasons Various types of microbes congregate everywhere in and on the human body. Their presence maintains their host’s health in part by making it hard for disease-causing germs to gain access to the body. Several species, such as Bacteroides fragilis, also perform specific useful functions, including aiding in the development and regulation of the immune system (below, right).
  • 11. Case Study: How One Bacterial Species Helps Studies on mice raised in sterile conditions reveal that B. fragilis bacteria are crucial to maintaining the health of the intestines. In one experiment, germ-free mice that were given a strain of B. fragilis bacteria that produced the complex carbohydrate polysaccharide A did not develop inflammation of the intestine (colitis), whereas mice that were given a strain of B. fragilis bacteria that did not make PSA developed chronic inflammation of the gut. Investigators showed that the presence of PSA stimulated the development of regulatory T cells that in turn switched off the inflammatory T cells, thereby restoring health. Immune cells called dendritic cells pick up a molecule called polysaccharide A (PSA) from the B. fragilis cells and present it to undifferentiated T cells. 1 The bits and pieces of PSA stimulate the undifferentiated T cells to become regulatory T cells, which in turn produce substances that tamp down the aggressive efforts of in- flammatory T cells. 2 SO
  • 15. L. 16 ; 2 01 0 (B . f ra gi lis c as e st ud y) Urogenital tract Corynebacterium aurimucosum Ureaplasma parvum Skin Staphylococcus epidermidis
  • 16. Staphylococcus haemolyticus Pityrosporum ovale Corynebacterium jeikeium Trichosporon B. fragilis PSA manufactured by B. fragilis Dendritic cell Undifferen- tiated T cell Regulatory T cellsGut Inflamed area Inflammatory T cells © 2012 Scientific American© 2012 Scientific American
  • 17. 42 Scientific American, June 2012 cent more calories than do rodents with an intact microbiome to gain the same amount of weight.) The study of the microbiome has even partially rehabilitat- ed the reputation of one disease-causing bacterium called Heli- cobacter pylori. Fingered by Australian physicians Barry Mar - shall and Robin Warren in the 1980s as the causative agent of peptic ulcers, H. pylori is one of the few bacteria that seem to thrive in the acidic environment of the stomach. While contin- ued use of medicines known as nonsteroidal anti-inflammatory drugs, or NSAIDs, had long been known to be a common cause of peptic ulcers, the finding that bacteria contributed to the condition was remarkable news. After Marshall’s discovery, it became standard practice to treat peptic ulcers with antibiot- ics. As a result, the rate of H. pylori–induced ulcers has dropped by more than 50 percent. Yet the matter is not so simple, says Martin Blaser, now a pro- fessor of internal medicine and microbiology at New York Uni - versity who has studied H. pylori for the past 25 years. “Like ev- eryone, I started working on H. pylori as a simple pathogen,” he says. “It took a few years for me to realize that it was actually a commensal.” In 1998 Blaser and his colleagues published a study showing that in most people, H. pylori benefits the body by help- ing to regulate levels of stomach acids, thus creating an environ- ment that suits itself and its host. If the stomach churns out too much acid for the bacteria to thrive, for example, strains of the bug that contain a gene called cagA start producing proteins that
  • 18. signal the stomach to tone down the flow of acid. In susceptible people, however, cagA has an unwelcome side effect: provoking the ulcers that earned H. pylori its nasty rap. A decade later Blaser published a study suggesting that H. py- lori has another job besides regulating acid. For years scientists have known that the stomach produces two hormones involved in appetite: ghrelin, which tells the brain that the body needs to eat, and leptin, which—among other things—signals that the stomach is full and no more food is needed. “When you wake up in the morning and you’re hungry, it’s because your ghrelin lev- els are high,” Blaser says. “The hormone is telling you to eat. Af- ter you eat breakfast, ghrelin goes down,” which scientists refer to as a postprandial (from the Latin word prandium, for “a meal”) decrease. In a study published last year, Blaser and his colleagues looked at what happens to ghrelin levels before and after meals in people with and without H. pylori. The results were clear: “When you have H. pylori, you have a postprandial decrease in ghrelin. When you eradicate H. pylori, you lose that,” he says. “What that means, a priori, is that H. pylori is involved in regu- lating ghrelin”—and thus appetite. How it does so is still largely a mystery. The study of 92 veterans showed that those treated with antibiotics to eliminate H. pylori gained more weight in compar- ison to their uninfected peers—possibly because their ghrelin level stayed elevated when it should have dropped, causing them to feel hungry longer and to eat too much. Two or three generations ago more than 80 percent of Amer-
  • 19. icans played host to the hardy bug. Now less than 6 percent of American children test positive for it. “We have a whole genera- tion of children who are growing up without H. pylori to regu- late their gastric ghrelin,” Blaser says. Moreover, children who are repeatedly exposed to high doses of antibiotics are likely ex- periencing other changes in their microbial makeup. By the age of 15, most children in the U.S. have had multiple rounds of anti- biotic treatment for a single ailment—otitis media, or ear infec- tion. Blaser speculates that this widespread treatment of young children with antibiotics has caused alterations in the composi - tions of their intestinal microbiome and that this change may help explain rising levels of childhood obesity. He believes that the various bacteria within the microbiome may influence whether a certain class of the body’s stem cells, which are rela - tively unspecialized, differentiate into fat, muscle or bone. Giv- ing antibiotics so early in life and thereby eliminating certain microbial species, he argues, interferes with normal signaling, thereby causing overproduction of fat cells. Could the accelerating loss of H. pylori and other bacteria from the human microbiome, along with societal trends—such as the easy availability of high-calorie food and the continuing decline in manual labor—be enough to tip the balance in favor of a global obesity epidemic? “We don’t know yet whether it’s going to be a major or minor part of the obesity story, ” he says, “but I’m betting it’s not trivial.” The widespread use of antibiotics is not the only culprit in the unprecedented disruption of the human microbiome in Blaser’s view. Major changes in human ecology over the past century have contributed as well. The dramatic increase in the past few decades in the number of deliveries by cesarean section obvi -
  • 20. ously limits the transfer through the birth canal of those all -im- portant strains from Mom. (In the U.S., more than 30 percent of all newborns are delivered by C-section, and in China—land of one child per couple—the operation is responsible for nearly two thirds of all births to women living in urban areas.) Smaller family sizes throughout the world mean fewer siblings, who are a prime source of microbial material to their younger siblings during early childhood years. Even cleaner water—which has saved the lives of untold millions—exacts a toll on the human microbiome, reducing the variety of bacteria to which we are ex- posed. The result: more and more people are born into and grow up in an increasingly impoverished microbial world. A DELICATE BALANCE as the ongoing studies of B. thetaiotaomicron and H. pylori il - lustrate, even the most basic questions about what these bacte- rial species are doing in the body lead to complicated answers. Going one step further and asking how the body responds to the presence of all these foreign cells in its midst introduces even greater complexity. For one thing, the traditional understanding of how the immune system distinguishes the body’s own cells (self ) from genetically different cells (nonself ) suggests that our molecular defenses should be in a constant state of war against these myriad interlopers. Why the intestines, for example, are not the scene of more pitched battles between human immune cells and the trillions of bacteria present is one of the great, as yet unsolved mysteries of immunology. The few clues that exist offer tantalizing insights into the balancing act between the microbiome and human immune cells that has taken some 200,000 years to calibrate. Over the eons the immune system has evolved numerous checks and bal - ances that generally prevent it from becoming either too aggres - sive (and attacking its own tissue) or too lax (and failing to rec-
  • 21. ognize dangerous pathogens). For example, T cells play a major role in recognizing and attacking microbial invaders of the © 2012 Scientific American June 2012, ScientificAmerican.com 43 body, as well as unleashing the characteristic swelling, redness and rising temperature of a generalized inflammatory response to infection by a pathogen. But soon after the body ramps up its production of T cells, it also starts producing so-called regulato- ry T cells, whose principal function seems to be to counteract the activity of the other, pro-inflammatory T cells. Normally the regulatory T cells swing into action before the pro-inflammatory T cells get too carried away. “The problem is that many of the mechanisms that these proinflammatory T cells use to fight infection—for example, the release of toxic compounds—end up blasting our own tissues,” says Caltech’s Mazmanian. Fortunately, the regulatory T cells produce a pro- tein that restrains the proinflammatory T cells. The net effect is to tamp down inflammation and prevent the immune system from attacking the body’s own cells and tissues. As long as there is a good balance between belligerent T cells and more tolerant regulatory T cells, the body remains in good health. For years researchers assumed that this system of checks and balances was generated entirely by the immune system. But in yet another example of how little we control our own fate, Mazmanian and oth- ers are starting to show that a healthy, mature immune system depends on the constant inter-
  • 22. vention of beneficial bacteria. “It goes against dogma to think that bacteria would make our immune systems function better,” he says. “But the picture is getting very clear: the driving force behind the features of the immune system are commensals.” Mazmanian and his team at Caltech have dis- covered that a common microorganism called Bacteroides fragilis, which lives in some 70 to 80 percent of people, helps to keep the immune sys- tem in balance by boosting its anti-inflammatory arm. Their research began with observations that germ-free mice have defective immune systems, with diminished function of regulatory T cells. When the re- searchers introduced B. fragilis to the mice, the balance between the pro-inflammatory and anti-inflammatory T cells was re- stored, and the rodents’ immune systems functioned normally. But how? In the early 1990s researchers started characteriz- ing several sugar molecules that protrude from the surface of B. fragilis—and by which the immune system recognizes its pres- ence. In 2005 Mazmanian and his colleagues showed that one of these molecules, known as polysaccharide A, promotes matura- tion of the immune system. Subsequently, his laboratory re- vealed that polysaccharide A signals the immune system to make more regulatory T cells, which in turn tell the pro-inflam- matory T cells to leave the bacterium alone. Strains of B. fragilis that lack polysaccharide A simply do not survive in the mucosal lining of the gut, where immune cells attack the microbe as if it were a pathogen. In 2011 Mazmanian and his colleagues published a study in Sci - ence detailing the full molecular pathway that produces this ef-
  • 23. fect—the first such illumination of a molecular pathway for mutu- alism between microbe and mammal. “B. fragilis provides us with a profoundly beneficial effect that our own DNA for some reason doesn’t provide,” Mazmanian says. “In many ways, it co-opts our immune system—hijacks it.” Unlike pathogens, however, this hi- jacking does not inhibit or reduce our immune system perfor- mance but rather helps it to function. Other organisms may have similar effects on the immune system, he notes: “This is just the first example. There are, no doubt, many more to come.” Alas, because of lifestyle changes over the past century, B. fragilis, like H. pylori, is disappearing. “What we’ve done as a society over a short period is completely change our association with the microbial world,” Mazmanian says. “In our efforts to distance ourselves from disease-causing infectious agents, we have probably also changed our associations with beneficial or - ganisms. Our intentions are good, but there’s a price to pay.” In the case of B. fragilis, the price may be a significant in- crease in the number of autoimmune disorders. Without poly- saccharide A signaling the immune system to churn out more regulatory T cells, the belligerent T cells begin attacking every- thing in sight—including the body’s own tissues. Mazmania n contends that the recent sevenfold to eightfold increase in rates of autoimmune disorders such as Crohn’s disease, type 1 diabe - tes and multiple sclerosis is related to the de- cline in beneficial microbes. “All these diseases have both a genetic component and an environ- mental component,” Mazmanian says. “I believe
  • 24. that the environmental component is microbi- otic and that the changes are affecting our im- mune system.” The microbial shift that comes with changes in how we live—including a de- crease in B. fragilis and other anti-inflammato- ry microbes—results in the underdevelopment of regulatory T cells. In people who have a ge- netic susceptibility, this deviation may lead to autoimmunity and other disorders. Or at least that is the hypothesis. At this stage in the research, the correlations in humans be- tween lower microbial infections and increased rates of immune disease are only that—correla- tions. Just as with the obesity issue, teasing apart cause and effect can be difficult. Either the loss of humanity’s in- digenous bugs have forced rates of autoimmune diseases and obesity to shoot up or the increasing levels of autoimmunity and obesity have created an unfavorable climate for these native bugs. Mazmanian is convinced that the former is true—that changes in the intestinal microbiome are contributing significantly to rising rates of immune disorders. Yet “the burden of proof is on us, the scientists, to take these correlations and prove that there is cause and effect by deciphering the mechanisms underlying them,” Mazmanian says. “That is the future of our work.” WE HAVE COMPLETELY CHANGED OUR ASSOCIATION
  • 25. WITH THE MICROBIAL WORLD. THERE IS A PRICE TO PAY FOR OUR GOOD INTENTIONS. M O R E T O E X P L O R E Who Are We? Indigenous Microbes and the Ecology of Human Diseases. Martin J. Blaster in EMBO Reports, Vol. 7, No. 10, pages 956–960; October 2006. www.ncbi.nlm.nih. gov/pmc/articles/PMC1618379 A Human Gut Microbial Gene Catalogue Established by Metagenomic Sequencing. Junjie Qin et al. in Nature, Vol. 464, pages 59–65; March 4, 2010. Has the Microbiota Played a Critical Role in the Evolution of the Adaptive Immune System? Yun Kyung Lee and Sarkis K. Mazmanian in Science, Vol. 330, pages 1768–1773; December 24, 2010. www.ncbi.nlm.nih.gov/pmc/articles/PMC3159383 SCIENTIFIC AMERICAN ONLINE For an interactive feature about some of the key microbial species found in and on the body, visit ScientificAmerican.com/jun2012/microbiome- graphic
  • 26. © 2012 Scientific American Title of Assignment Professional Identity of the Nurse: Scope of Nursing Practice Purpose of Assignment: According to Larson, Brady, Engelmann, Perkins, and Shultz (2013), “the development of professional identity is a continuous process that begins with admission to the nursing program and evolves throughout one’s professional career in a dynamic and fluid process where interacting relationship of education and practice lead to self-reflection, growth, and human flourishing” (p. 138). Larson, J., Brady, N., Engelmann, L., Perkins, B., & Shultz, C. (2013). The formation of professional identity in nursing. Nursing Education Perspectives.34 (2). p 138. Course Competency(s): Describe the foundations of nursing practice. Explain the roles and scope of practice for members of the intraprofessional team. Describe principles of effective communication in the healthcare setting. Instructions: This course includes a project with three parts. Each part builds off prior knowledge to help you create your nurse professional identity. In the first part, you examine the role of the nurse and scope of practice, which will help you identify the nurses’ role. In the second part, you describe the importance of the code of ethics in nursing, and examine the standards of nursing practice for the role you are obtaining during the nursing program. The final submission requires you to use the first two parts of your assignment to explain your belief of caring in nursing, describe your professional identity, and identify a potential professional organization that you may join to help support your development.
  • 27. Content: Prepare a two to three page written assignment that includes the following: · Introduction to the assignment (sections of the assignment) · Describe the importance of the code of ethics in nursing · Identify the American Nurses Association Standards of Practice for the licensure you are obtaining (LPN or RN) · Conclusion (reflect on the criteria of the assignment) · Use at least two credible resources to support your findings. For example, one of the resources could be the ANA Standards of Practice, and another resource could be the ANA Code of Ethics. These resources must be integrated into the body of your paper using at least two in-text citations. Be sure to use proper APA format and style. Format: · Two to three page written assignment · Standard American English (correct grammar, punctuation, etc.) · Logical, original and insightful · Professional organization, style, and mechanics in APA for mat · Run your paper through Grammarly and make corrections to identified errors before submission. Note: You must use the following link to create your Grammarly account. You must use your Rasmussen student email address: https://www.grammarly.com/signin?page=edu Resources: Rasmussen College Online Library School of Nursing > Your Career > Jobs and Outlook > Professional Associations Tab · https://guides.rasmussen.edu/nursing/jobsandoutlook Writing Help Rasmussen College offers many different resources to support your academic writing.
  • 28. · Writing Help: How do I access writing support? Research Help School of Nursing Online Guide > Nursing Research https://guides.rasmussen.edu/nursing/research Before you begin your search, it is important to understand: · What is a scholarly or peer reviewed article? · What is the difference between evidence-based articles and scholarly, research articles? · How do I know if a source is credible? Use the links below when you are ready to start searching the online library: · How do I find scholarly/peer-reviewed nursing articles? · How do I find articles about nursing best practices? · Discovery database: What is it, and how do I use it? APAHelp New to APA? Watch this video for a brief introduction: · APA Quick Start Want a more in-depth introduction to APA? Watch the 30 minute APA Basics webinar: · APA in 30 Minutes The APA Guide contains all of the information you need to create a research paper in the APA style, including: · APA Sample Paper · APA Paper Template · Examples of Reference list citations · In-text citations · Formatting an APA paper including the cover page Integrating resources into your writing is a crucial writing skill. Watch this video on how to paraphrase, summarize, and quote
  • 29. resources. · Integrate outside resources into your academic writing Learn more about creating a references list and how NoodleTools can help you by watching the webinar below or view our series of short videos: · APA Reference List and NoodleTools Software · NoodleTools Video Series Grading Rubric: Total Possible Points = 100 Levels of Achievement Criteria Emerging Competence Proficiency Mastery Introduction (10 Pts) Initial introduction does not include explanations of the sections of the paper. Failure to submit introduction will result in zero points for this criteria. Introduction includes a brief explanation for the sections of the paper. Introduction includes a clear explanation of the sections of the paper and supporting evidence. Introduction includes a comprehensive explanation for the sections of the paper with detailed examples and supporting evidence. Points: 6 Points: 8 Points: 9 Points: 10 Code of Ethics (35 Pts)
  • 30. Code of ethics section lacks suggestions and/or supporting evidence. Failure to submit this section will result in zero points for this criteria. Code of ethics section includes minimal discussion on ethics with limited supporting evidence. Code of ethics section includes discussion with examples and supporting evidence. Code of ethics section offers substantial contributions and detailed examples with supporting evidence. Points: 21 Points: 28 Points: 31 Points: 35 Standards of Practice (35 Pts) Standards of Practice lacks presentation and/or supporting evidence. Failure to submit this section will result in zero points for this criteria. Standards of Practice includes minimal presentation with limited supporting evidence. Standards of Practice includes presentation with examples with supporting evidence. Standards of Practice includes substantial presentation and detailed examples with supporting evidence. Points: 21 Points: 28 Points: 31 Points: 35 Conclusion (10 Pts) Conclusion lacks a summary of the sections of the paper. Failure to submit this section will result in zero points for this
  • 31. criteria. Conclusion includes minimal summary of the sections of the paper. Conclusion includes a summary of the paper with supporting evidence. Conclusion includes a substantial summary of the paper with detailed examples with supporting evidence. Points: 6 Points: 8 Points: 9 Points: 10 Spelling and Grammar (5 Pts) Spelling and grammar contain substantial errors that make sentences and/or paragraphs incoherent. Spelling and grammar errors occur but are inconsistent. Paragraphs and sentences are coherent but may exhibit spelling errors, run-on’s or fragments, and/or improper verb tense usage. Displays proper grammar application, and writing contains minimal to no spelling errors. May contain rare improper uses of words (ex., their vs. there), a misplaced modifier, or a run-on sentence, but does not detract from the overall understanding of the sentence and/or paragraph. Demonstrates an exemplary application of spelling and grammar. Points: 2 Points: 3 Points: 4
  • 32. Points: 5 APA Citation (5 Pts) Citations do not follow APA Style. Quotations, paraphrases, and summaries are not cited, or there is no attempt to cite them using APA style. Errors in APA citations are noticeable and may detract from the ability to locate the original source (for example, no title provided, year of publication is missing, no punctuation). Errors in APA citations are less noticeable and do not detract from the ability to locate the original source (for example, a missing or misused comma or period, missing parentheses, author name not properly abbreviated, indentation is misaligned). APA citations are free of style and formatting errors. Points: 2 Points: 3 Points: 4 Points: 5 Nested or Networked? Future Directions for Ecological Systems Theory Jennifer Watling Neal and Zachary P. Neal, Michigan State University Abstract
  • 33. Bronfenbrenner’s ecological systems theory (EST) is among the most widely adopted theoretical frameworks for studying individuals in ecological contexts. In its traditional formulation, different levels of ecological systems are viewed as nested within one another. In this article, we use Simmel’s notion of intersecting social circles and Bronfenbrenner’s earlier writing on social networks to develop an alternative ‘net- worked’ model that instead views ecological systems as an overlapping arrangement of structures, each directly or indirectly connected to the others by the direct and indirect social interactions of their participants. We redefine each of the systems discussed by EST—micro, meso, exo, macro, and chrono—based on patterns of social interaction, and then illustrate how this alternative model might be applied in the classic context of the developing child. We conclude by discussing future directions for how the networked model of EST can be applied as a conceptual framework, arguing that this approach offers developmental researchers with a more precise and flexible way to think about ecological contexts. We also offer some initial suggestions for moving a networked EST model from theory to method. Keywords: ecological systems theory; social networks; context; Bronfenbrenner Introduction Originally proposed by Bronfenbrenner (1977, 1979), ecological
  • 34. systems theory (EST) has been widely adopted by developmental psychologists interested in understanding individuals in context. Indeed, Google Scholar reveals that The Ecology of Human Development (Bronfenbrenner, 1979), which first outlined EST, has been cited nearly 15 000 times as of September 2012. Conceptually, EST has been used to motivate a focus on setting-level influences, guiding the development of contextual models to explain a range of phenomena including urban adolescent psychological and academic outcomes (e.g., Seidman, 1991), developmental risk and protective factors for substance use (e.g., Szapocznik & Coatsworth, 1999), youth activity engagement (e.g., Rose-Krasnor, 2009), and family influences on gender development (e.g., McHale, Crouter, & Whiteman, 2003). Empirically, developmental studies have used Correspondence should be addressed to Jennifer Watling Neal, Department of Psychology, 316 W. Physics Road., 127A Psychology Building, Michigan State University, East Lansing, MI 48824, USA. Email: [email protected] Social Development Vol 22 No. 4 722–737 November 2013 doi: 10.1111/sode.12018 © 2013 John Wiley & Sons Ltd EST to identify contextual predictors or points of intervention that lie beyond the
  • 35. individual. For instance, studies of children and youth have often examined aspects of the peer, family, classroom/school, and neighborhood microsystems (e.g., Chipuer, 2001; Criss, Shaw, Moilanen, Hitchings, & Ingoldsby, 2009; Gest & Rodkin, 2011; Gifford-Smith & Brownell, 2003; Seidman et al., 1995) or mesosystemic interactions between these microsystems (e.g., Durlak et al., 2007; Serpell & Mashburn, 2012). However, in general, empirical exploration of exosystems and macrosystems in devel- opmental studies applying an EST framework remains less frequent. Although EST is widely recognized for underscoring the importance of interdepend- ent and multilevel systems on individual development, the precise relationships of systems to one another remain elusive. Bronfenbrenner (1979) originally described ecological systems at different levels as nested within one another, giving rise to EST’s classic graphic portrayal as a set of concentric circles. However, in this article, we argue that conceptualizing ecological systems as nested obscures the relationships between them. Instead, we argue that ecological systems should be conceptualized as networked, where each system is defined in terms of the social relationships surround- ing a focal individual, and where systems at different levels relate to one another in an overlapping but non-nested way. Defining ecological systems in network terms not only provides greater theoretical clarity but also yields a form
  • 36. of EST that more closely matches Bronfenbrenner’s (1945) early recognition of the role of social networks in shaping development. To build this argument, we begin by reviewing the traditional conceptualization of ecological systems as nested and highlight recent modifications to the theory. Then, drawing on Simmel’s (1955 [1922]) notion of intersecting social circles, we discuss how ecological systems are better conceptualized as networked rather than nested. We illustrate the networked model of EST using the hypothetical example of a developing child. Finally, we discuss implications of this new conceptualization of ecological systems theory for future research. Ecological Systems as Nested: The Traditional Model Bronfenbrenner first proposed EST in a series of seminal publications in the 1970s and 1980s. We focus on the theory and definitions provided in The Ecology of Human Development (Bronfenbrenner, 1979), which are largely consistent with his earlier and later writing (Bronfenbrenner, 1977, 1986a, 1986b), and which are summarized in Table 1. Bronfenbrenner (1979) described the topology of the ecological environment as ‘a nested arrangement of structures, each contained within the next’, which must be examined as an interdependent whole to fully understand the forces surrounding a developing individual (p. 22). This approach represented a
  • 37. sharp departure from more traditional approaches to developmental psychology of the day, which he derided as ‘the science of the strange behavior of children in strange situations with strange adults for the briefest possible periods of time’ (p. 19). His initial articulation of EST identified four such structures, or systems—the microsystem, mesosystem, exosystem, and macrosystem—that are nested around a focal individual like a set of concentric circles, or as Bronfenbrenner suggested, a set of Russian dolls (i.e., a matryoshka doll). Thus, nearly all graphical depictions of EST rely on some variation of the concentric circles model shown in Figure 1. Bronfenbrenner (1979) viewed each system as arising from a setting, which he defined as ‘a place where people can readily engage in face-to- face interaction’ Nested or Networked? 723 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 T ab le 1. N
  • 92. s ar o u n d h im /h er . 724 Jennifer Watling Neal and Zachary P. Neal © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 (p. 22). At the lowest level of his nested hierarchy, microsystems are settings where the focal individual plays a direct role, has direct experiences, and has direct social interactions with others. Using the classic example of a developing child (see Figure 1), the family is a microsystem where the child plays a direct role (e.g., daughter, sibling), has direct experiences (e.g., enjoying family meals), and has direct social interactions with others (e.g., reading with mom, teasing baby brother).
  • 93. Mesosystems, within which microsystems are nested, include social interactions between two of the focal individual’s settings. In our example, a mesosystem could include a meeting between a parent (from the child’s family setting) and teacher (from the child’s school setting) about a child’s classroom behavior. This meeting represents a social interaction between members of the child’s family microsystem and school microsystem. Exosystems, within which mesosystems are nested, include settings that influence the focal individual but in which the focal individual does not directly participate. An individual child generally does play a role in or have direct experiences in the education policy-making community, but educational policies nonetheless influence the child’s classroom and school experiences. For example, a district decision to consolidate schools to save money may lead to larger classroom and school sizes, changing the microsystems in which children interact. Finally, mac- rosystems, within which exosystems are nested, include broad cultural influences or ideologies that have long-ranging consequences for the focal individual. For instance, societal views that place emphasis on teacher accountability and standard- ized test scores have led to policies such as the No Child Left Behind Act of 2001 that have implications for how children experience schooling. In addition to the four core systems of EST, Bronfenbrenner (1986a, 1986b) later introduced the chrono-
  • 94. system, a system reflecting change or continuity across time that influences each of the other systems. Transitions like a child’s move from middle to high school or the onset of puberty are part of the chronosystem. Microsystem ‘The family’ Mesosystem ‘Parent-teacher’ Exosystem ‘Education policy’ Macrosystem ‘Societal views on education’ Figure 1. Nested Model of Ecological Systems Originally Proposed by Bronfenbren- ner (1979). Nested or Networked? 725 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 Although nesting is a hallmark of EST, many of the systems in EST are simply not nested in nature. In our example of a developing child above, the family microsystem is nested inside the educational policy-making exosystem, but it makes little sense to view the former as a subset of the latter. Instead these are two
  • 95. distinct systems, arising in distinct settings—one that contains the child and one that does not—that influence one another. Thus, we argue that viewing ecological systems as nested undermines the theoretical coherence and conceptual utility of EST. A focus on social interactions can help clarify how ecological systems are connected. Social interactions are a key component of EST and, perhaps not surprisingly, as Bronfenbrenner (1945) was a pioneer in the earliest days of social network research. Bronfenbrenner (1979) clearly defined both the microsystem and the mesosystem in terms of social interactions. For example, he noted that the analysis of the microsystem ‘must take into account the indirect influence of third parties on the interaction between members of a dyad’ because a focus on dyadic social interactions alone ignores the wider social context and is thus insufficient to capture the social forces bearing on the focal individual (proposition E; p. 68). Similarly, he defined mesosystems as arising from, among other types of interconnections, the ‘intermediate links in a social network’ (p. 25). However, despite its explicit focus on social interactions, applications of EST typically have not focused their attention on patterns of social interactions. For example, Szapocznik and Coatsworth (1999) noted that the examination of mesosys- tems instead typically focuses on the interdependence of functioning across multiple domains in general terms (e.g., the effects of functioning at
  • 96. home on functioning at school). Thus, they call for a return to the exploration of social interactions that comprise both microsystems and mesosystems. In the current article, we answer this call, and we push it further by presenting not simply these two systems but also the whole of EST through the lens of networks of social interactions. Ecological Systems as Networked: A Social Network Model Although not referenced in his early work on social networks (Bronfenbrenner, 1945) or formal articulation of EST (Bronfenbrenner, 1979), Bronfenbrenner’s theo- retical orientations bear a close resemblance to the work of Georg Simmel (1858– 1918). For example, Bronfenbrenner’s call for ecologically minded psychologists to look beyond the dyad explicitly parallels Simmel’s (1950 [1908]) extensive writing on the differences between dyads and triads, and his contention that socially inter- esting phenomena arise only in settings with more than two actors. Still more directly relevant to our reformulation of EST is Simmel’s (1955 [1922]) essay on social circles, which closely resemble what Bronfenbrenner called systems. Simmel recognized that when circles/systems are concentrically arranged, ‘participation in the smallest of these . . . already implies participation in the larger’ (p. 147), and thus that the forces impacting a person’s development are entirely determined by the
  • 97. smallest circle/system in which he or she participates. Simmel and other early social theorists (e.g., Durkheim 1984 [1893]; McPherson 2004) viewed such an arrange- ment of social circles as the hallmark of a ‘primitive’ society with a relatively undif- ferentiated social structure. For example, in feudal society governed by tradition and custom, membership in a particular family determined one’s trade, and one’s trade determined one’s friends (i.e., other guild members) and one’s place of residence. Thus, family membership—the smallest social circle/system— fully determined the ecological forces impacting one’s development. 726 Jennifer Watling Neal and Zachary P. Neal © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 In contrast, Simmel hypothesized that the range of forces impacting a person’s development ‘will be greater when the [circles] which influence him are juxtaposed than if they are concentric’ (p. 147). Bronfenbrenner offered the same hypothesis more than 50 years later, noting that ‘the developmental status of the individual is reflected in the substantive variety and structural complexity of the . . . activities which she initiates’ (Bronfenbrenner, 1979, p. 55). Clearly, both Simmel and Bronfenbrenner appreciated that the ecological influences brought to bear on
  • 98. individuals are far more complex than a simple nested/concentric configuration of social circles/systems could adequately capture. However, simply redrawing the traditional graphic representation of EST using intersecting, rather than nested or concentric, circles does little to clarify the underlying theoretical model. For this job, we turn to social networks and the importance of patterns of social interaction, with which both Simmel and Bronfen- brenner were intimately familiar. The fundamental building block of EST is the setting; thus, any attempt to re-theorize EST must begin here. For Bronfenbrenner (1979), ‘a setting is a place where people can readily engage in face-to-face interaction’ (p. 22, emphasis added), and thus it has a primary spatial dimension and a secondary interactional dimension. However, when it comes to forces that influence individuals’ development, are inter- actional factors really secondary to spatial ones? Compare the developmental conse- quences of couple A interacting lovingly at home, and couple B interacting lovingly on vacation. A social network, or structuralist, perspective contends that common forces are likely to shape the development of these two couples because they are engaged in common patterns of interaction, even if in different locations. Similarly, compare the developmental consequences of couple A interacting lovingly at home, and couple C fighting at home. Here, a network perspective contends that
  • 99. different forces are likely to shape the development of these two couple because they are engaged in different patterns of social interaction, even if in the same location. Thus, although we continue to view settings as the fundamental building block of EST, adopting a network per- spective, we offer a definition that mirrors but inverts Bronfenbrenner’s by focusing primary attention of patterns of social interaction: a setting is a set of people engaged in social interaction, which necessarily occurs in, and is likely affected by the features of, a place (see Table 1). This focus on patterns of social interaction has previously been advocated in the specific context of EST by Szapocznik and Coatsworth (1999), more generally in community psychology by Seidman (1988), and across the social sciences since the initial sociometric work of Moreno (1934). Notably, although our conception of a setting places primary attention on the patterns of social interaction, it does not reject that spatial factors may nonetheless play an important role. Having defined settings as sets of interacting people, we begin our networked reformulation of EST by observing that the ecological environment is an overlapping arrangement of structures, each directly or indirectly connected to the others by the direct and indirect social interactions of their participants. This definition not only highlights that systems are not necessarily nested within one another but also clarifies
  • 100. that it is individuals’ patterns of social interactions with other another that determine how systems relate to one another. Moreover, it allows each type of system to be precisely defined in terms of patterns of interaction. Figure 2 illustrates a hypothetical pattern of social interactions—that is, a social network—among nine people (labeled A thru I), with the focal individual represented by the shaded circle in the center. Each set of people who all interact with one another—that is, a setting—is enclosed by a dashed circle. For example, persons A thru Nested or Networked? 727 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 D all interact with one another and thus constitute a setting. From these settings, it is possible to identify ecological systems using definitions that closely parallel those originally proposed by Bronfenbrenner. First, a microsystem is a setting—or set of people engaged in social interaction—that includes the focal individual. In this example, there are three microsystems: one on the left composed of A–B–C–D, one on the right composed of A–E–F–G, and one that overlaps with these two composed of A–D–E. Second, a mesosystem is a social interaction between participants in different
  • 101. settings that both include the focal individual. Here, the relationship between D, who participates in the setting on the left, and E, who partici pates in the setting on the right, is a mesosystemic interaction. Finally, an exosystem is a setting—or set of people engaged in social interaction—that does not include, but whose participants interact directly or indirectly with, the focal individual. This example contains one setting, composed of G–H–I, that is an exosystem. Together, these individuals constitute an interactional setting that does not contain the focal individual, but whose participants are each directly (e.g., person G) or indirectly (e.g., persons H and I, by two steps) connected to the focal individual. As the simple example in Figure 2 illustrates, adopting this approach highlights the intersecting, non-nested character of ecological systems. For example, different microsystems can overlap when they involve distinct sets of individuals participating in different settings. Similarly, the mesosystem is ipso facto a social interaction that requires the intersection of two microsystems. However, by more robustly specifying the relationships between systems at different ecological levels, the networked model of EST also expands the utility of the theory by making it possible to consider the ecological environment from the perspective of different focal individuals. Suppose the simple social network shown in Figure 2 represented the entire social universe. If
  • 102. person A is the focal individual, as the figure illustrates, this person’s development is influenced by three microsystems, one mesosystem, and one exosystem. However, applying the same network-based definitions of ecological systems, it is possible to consider what systems shape the development of, for example, person C instead. In contrast to person A, person C’s development is influenced by one microsystem (A–B–C–D), no mesosystems, and three exosystems (A–D–E, A–E–G–F and G–H–I). This highlights that the specific nature and configuration of ecological systems Microsystem Exosystem Microsystem A B C D E F G HI Microsystem
  • 103. Mesosystemic interaction Figure 2. Networked Model of Ecological Systems, Focused on Person A. 728 Jennifer Watling Neal and Zachary P. Neal © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 influencing the development of an individual depends on, must be considered from, the perspective of the focal individual. Although A–E–G–F is a microsystem for person A, it is an exosystem for person C. To this point, we have considered only the first three of EST’s five systems. The macrosystem and chronosystem are not built from settings, but rather refer to forces that shape the patterns of social interactions that define settings. First, the macrosystem is the set of social patterns that govern the formation and dissolution of social interactions between individuals, and thus the relationship among ecological systems. For example, the social pattern known as homophily refers to individuals’ tendency to interact with others who share a social status (e.g., race, gender, and so on) or who share an attitude or value orientation (e.g., commitment to social justice) (Lazarsfeld &
  • 104. Merton, 1964; McPherson, Smith-Lovin, & Cook, 2001). Similarly, transitivity refers to the tendency for two individuals with a common acquaintance to interact as they are brought together in common settings, by common values, or with common goals (Feld, 1981). As enduring patterns in human social interaction, homophily and transitivity significantly determine the structure of social networks, and thus the configuration of ecological systems surrounding a focal individual. In addition to structural tendencies like homophily and transitivity, broad forces like legal, political, and cultural systems typically associated with the macrosystem also manifest their effects in the structure of social networks by shaping with whom one may, or is likely to, interact. Second, the chronosystem is the observation that patterns of social interactions between individu- als change over time, and that such changes impact the focal individual, both directly and by altering the configuration of ecological systems surrounding him/her. The modeling and analysis of dynamic social networks is an emerging area of study, with some seeking to understand how networks evolve endogenously (Robins, Pattison, Kalish, & Lusher, 2007), and others exploring how both natural (e.g., social develop- ment; Schaefer, Light, Fabes, Hanish, & Martin, 2010; Veenstra & Dijkstra, 2011) and intentional (e.g., interventions; Hawe, Shiell, & Riley, 2009) exogenous forces can modify network structures.
  • 105. A Hypothetical Example To concretely illustrate ecological systems as networked, in this section, we return to the classic example of a developing child used in Bronfenbrenner’s (1977, 1979, 1986a, 1986b) original formulation of EST. As noted earlier, EST has traditionally viewed the child as positioned at the center of a series of nested ecological systems leading from those most immediate to the child (e.g., microsystems such as the family and school) to those most distal (e.g., macrosystemic forces such as societal views on education) (see Figure 1). However, conceptualizing EST in terms of social networks leads to a strikingly different arrangement of the ecological systems surrounding the child. Following Simmel’s (1955 [1922]) conception of social circles, the child appears as part of an overlapping or intersecting set of ecological systems that are linked to one another through direct and indirect social interactions (see Figure 3). In Figure 3, the focal child in our example participates in two different settings. The setting on the left, composed of the daily familial interactions of the child, mother, father, and sibling can be identified as a microsystem because the focal individual (i.e., the child) is a participant. Moreover, it can be identified specifically as a family microsystem given the specific identities and roles of its participants and the content of their social interactions. The setting on the right, composed of
  • 106. the social interactions Nested or Networked? 729 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 between the child, teacher, coach, and principal can also be identified as a microsystem, again because the child is a participant, and more narrowly as a school microsystem given the identities and roles of its participants and the content of their social interac- tions. Both the family and the school settings have long been recognized as key microsystems impacting the children’s development. For example, researchers have studied social processes within the family including social support, hassles, parent– child relationships, and sibling relationships (e.g., Bokhorst, Sumter, & Westenberg, 2010; Bronfenbrenner, 1986a; McHale et al., 2003; Seidman et al., 1995). Similarly, they have also examined social processes within schools including teacher–student relationships (e.g., Hamre, Pianta, Downer, & Mashburn, 2008; Howes, 2000; Pianta, 1999; Troop-Gordon & Kopp, 2011), teacher practices (e.g., Cappella & Neal, 2012; Gest & Rodkin, 2011), school social support (e.g., Bokhorst, Sumter, & Westenberg, 2010; Seidman et al., 1995), and peer interactions (see Gifford- Smith & Brownell, 2003 for review). However, although previous research has
  • 107. typically defined the boundaries and participants of microsystems in advance, a networked model of EST relies on the actual social interactions within the child’s life to locate them. This approach, focusing on actual patterns of social interaction rather than a priori expec- tations, mirrors Wellman’s (1988) recommendation that the social world be viewed as ‘composed of networks, not groups’ (p. 37). One social interaction, between the child’s mother and the teacher, bridges between these two microsystems. Because this social interaction occurs between participants in different settings that both include the focal individual, it can be identified as a mesosystem. More specifically, given the context of this cross - setting social interaction in our example, we identify it as a school/family mesosystem. Such family–school relationships may occur when parents or guardians meet with teachers at school conferences, volunteer in the classroom, or receive regular notes from teachers about their child’s progress, and are a main focus in educational practice and research (e.g., Epstein, 1995; Kelley, 1990; Serpell & Mashburn, 2012). In our example, perhaps the child’s mother regularly speaks with the teacher over the phone about her daughter’s MayorSuperintendent CHILD
  • 108. Father Principal TeacherMother Sibling Coach The Family Microsystem The School Microsystem The Education Policy Exosystem The School/Family Mesosystemic Interaction Figure 3. Hypothetical Example Illustrating a Networked Model of Ecological Systems 730 Jennifer Watling Neal and Zachary P. Neal © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 progress in class and has been able to build a relationship with the teacher through this experience. Defining the mesosystem as a relationship that bridges two microsystems allows researchers to study direct social interactions, which have been described as an ‘understudied phenomenon’ in assessments of the
  • 109. mesosystem (Szapocznik & Coatsworth, 1999, p. 346). Figure 3 also contains a setting—that is, a set of people engaged in social interaction—that does not include the child. This setting, located in the upper right corner, is composed of the social interactions among three actors in the educational policy area: the superintendent, mayor, and principal. Because the child does not actually participate in this setting, but nonetheless directly or indirectly interacts with its participants—here, directly with the principal, and indirectly with the superintend- ent and mayor via the principal—the setting can be identified as an exosystem. More specifically, given the roles of this setting’s participants and the content of their social interactions, we identify it as the education policy exosystem. The role of school administrators, government officials, and policy-makers in indirectly shaping chil- dren’s development has often been explored in educational research (e.g., Daly & Finnigan, 2010; Spillane & Thompson, 1997). For example, the mayor may start a healthy eating campaign in the city and may work with the superintendent and prin- cipal to eliminate unhealthy foods in the school cafeteria. These cafeteria changes will impact on the focal child’s school microsystem, and it may lead her to choose healthier options like fruits or vegetables at lunchtime. However, the focal child is only indirectly connected to the setting responsible for these changes.
  • 110. The configuration of the microsystems, mesosystem, and exosystem as intersecting in the networked model of EST illustrated by Figure 3 is notably different from their configuration as nested in the more traditional model of EST illustrated by Figure 1. For example, the traditional model of EST views microsystems as nested within mesosystems. However, it makes little sense to suggest that the family or school settings are nested within the mother–teacher relationship. To be sure, the family and school microsystems are affected by the mother–teacher relationship, but they are not inside of it. Instead, as the networked model highlights, mesosystemic interactions like those between a mother and teacher can more properly be understood as existing between intersecting microsystems. Similarly, the traditional model views the meso- system as nested within the exosystem. Again, it makes little sense to suggest that the mother–teacher relationship is nested within the education policy system. In fact, in our example, none of the participants in the mesosystem (i.e., the mother and teacher) are participants in the exosystem (i.e., the principal, superintendent, and mayor). The networked model of EST highlights that mesosystems and exosystems are distinctly different types of settings that could, but are not required to, overlap. Viewing eco- logical systems as a series of settings that intersect and overlap to varying degrees, as the networked model does, provides EST greater flexibility by
  • 111. not rigidly specifying that each system is wholly nested within the next, and also allows understandings about the relationships between different systems to more closely mirror reality. Although Figure 3 does not include an overt illustration of the macrosystem or chronosystem, a networked model of these two systems can still be applied to the developing child in our example. Identification of macrosystemic factors that influence the focal child involves considering the social patterns that influence the formation and dissolution of social interactions between individuals in the child’s social world. For example, examining Figure 3, the social pattern of homophily might be useful for explaining the mesosystemic relationship between the child’s mother and the Nested or Networked? 731 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 classroom teacher. Perhaps the mother and teacher are connected because they share a viewpoint—for example, that education is important—which leads to their increased social interaction and a strengthened relationship between them. Similarly, the social pattern of transitivity might help explain the relationship between the school principal
  • 112. and the mayor in the educational policy exosystem. The superintendent’s job is likely to require social interaction with both the principal and the mayor. Because both the principal and the mayor interact regularly with the superintendent, transitivity suggests that social interaction is likely to occur directly between the principal and the mayor as well, perhaps through joint meetings to discuss the implementation of a healthy foods initiative. The macrosystem is frequently associated with legal, political, and cultural phenom- ena, which may appear lacking in this networked perspective. However, because such macrosocial phenomena directly impact how individuals interact with one another, the networked perspective does not exclude their consideration. Several examples serve to illustrate. Firstly, consider the effect of a legal ruling requiring school desegregation (e.g., Brown v. Board of Education). Because such a ruling will alter the demographic composition of schools, it will directly impact the level of diversity of the focal child’s network. Secondly, consider the effect of a shift in the political structure of the school board, from one constituted by appointment to one constituted by democratic election. Such a shift may require members of the education policy exosystem to expand their networks in search of electoral support, thereby potentially altering the size of the exosystem and its relationship to the other systems. Finally, consider the effect of
  • 113. cultural practices surrounding gender, and specifically the difference between a culture that favors gender-separate education and one that favors coeducational institutions. Such a cultural value will directly impact the potential and actual gender homophily observed in the focal child’s network. The networked model of EST may be unable to capture all possible macrosocial phenomena, but likely no model could rise to this task. However, it can capture macrosocial phenomena to the extent that their effects are reflected in patterns of individuals’ social interactions. We believe that this is sufficient because macrosocial phenomena that do not affect individual s’ social interactions are not likely to have significant or observable impacts on individual development. The chronosystem reflects changes in patterns of social interaction over time and can also be applied to our hypothetical example of the developing child. Life transitions may shape and restructure the social interactions in the focal child’s life. As the focal child’s own patterns of social interaction change, and as the patterns of social inter- action of those indirectly connected to the focal chil d change, the location and rela- tionship of the ecological systems surrounding the focal child will shift. For example, at present, the focal child’s sibling is still a toddler and has not yet started attending school. However, within the next few years, he will start kindergarten in the same school as his sister, potentially leading to new mesosystemic
  • 114. interactions that bring the school and family microsystems closer together. Moreover, consistent with develop- mental research (e.g., Berndt, 1982; Larson, Richards, Moneta, Holmbeck, & Duckett, 1996), as our focal child moves into adolescence, she may spend less time interacting family members and more time interacting with peers at school or in the neighborhood, shifting relationships within, or even prompting the formation of new, microsystems. Finally, Figure 3 clearly illustrates how the specific nature and configuration of ecological systems influencing the development of an individual must be considered from the perspective of that individual. The focal child described in this example is shaped by a family microsystem, a school microsystem, a school–family mesosystem, 732 Jennifer Watling Neal and Zachary P. Neal © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 and an education policy exosystem. However, considering the social world outlined in Figure 3 from her sibling’s perspective leads to a different configuration. Although the sibling is part of the same family microsystem as his sister, he is still a toddler and is not currently enrolled in school. Thus, from his perspective, the school and the
  • 115. educational policy settings are both exosystems, to which he is indirectly connected through his sister. He does not directly participate in either the school or educational policy settings, but may still be influenced by his sister to eat his fruits and vegetables due to healthy eating habits that she picked up from her school’s new cafeteria policy. Future Directions for the Networked Model of EST In this article, we have argued that the ecological systems outlined in EST are more usefully conceptualized as networked rather than nested. In contrast to EST’s tradi- tional view of ecological systems as concentrically arranged in a nested configuration, a networked model of EST views ecological systems as overlapping and connected through direct and indirect social interactions. As a conceptual model of the forces impacting individuals’ development, the networked approach offers a number of advantages. Firstly, it shifts the focus of attention away from where individuals interact and toward how and with whom they interact, which is essential to the extent that human development is a social process. Secondly, it allows researchers to examine more complex relationships among ecological systems, including a multiplicity of different microsystems that only partially overlap, and mesosystems and exosystems that bridge these microsystems. Thirdly, it offers a way to more fully incorporate Bronfenbrenner’s (1979) ‘recognition that environmental events
  • 116. and conditions outside any immediate setting containing the person can have a profound influence on behavior and development’ (p. 18, emphasis added). Although many applications of EST focus primarily on the microsystem, it is not for researchers’ lack of interest in higher order systems but rather for the daunting ambiguity of these systems. The networked model provides more theoretically consistent definitions that clearly specify not only what each system of composed of but also how each system is related to the others. Finally, by more explicitly incorporating social networks into EST, it offers a path for moving from theory to method. From Theory to Method As a theory, EST only specifies constructs, but it does not necessarily specify how those constructs should be empirically operationalized in practice. Thus, both the traditional nested model and our proposed networked model rely on the construct of ‘settings’ as the fundamental building block of ecological systems, but neither model offers a precise empirical operationalization. However, by focusing attention of pat- terns of social interaction, the networked model offers the possibility of using the precise tools of social network analysis to move EST from a theory to a method. A complete discussion and formal validation of network analytic operationalizations of the setting construct would go beyond the scope of this article,
  • 117. but we briefly consider some possibilities that may be useful in the future translation of our theoretical reformulation of EST into a measurement methodology. We have defined a setting as a set of people engaged in social interaction. Although such a broad definition is appropriate for a theoretical construct, it is too ambiguous for an empirical operationalization, leaving open questions about the necessary amount of Nested or Networked? 733 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 social interaction and the delineation of members from non- members. However, the social network concept of a clique offers some precise answers to such questions, and thus some potential operational definitions of a setting. Moreover, just as settings come in many forms—some are small and intimate whereas others are large and fluid—the network concept of clique has multiple operational definitions. Figure 4 illustrates some conceptions of a network clique that may be useful for operationalizing the construct of settings in EST. The simplest and most restrictive, the maximal complete subgraph, defines a clique as a set of people in which every member directly interacts with every other member (Scott, 2000; Wasserman & Faust,
  • 118. 1994). In Figure 4, there are three examples of a maximal complete subgraph: A–B–C, D–E–F and X–Y–Z. This is implicitly the operationalization of setting we have used in the examples discussed above. However, in practice, this conception of a clique might be most appropriate for defining a small setting, such as a family, where all members are likely to directly interact with one another whereas more inclusive conceptions may be necessary for operationalizing larger settings. An N-clique is a set of people in which every member is no more than N steps away from every other member, and thus in which members interact with one another either directly or indirectly through just a few intermediaries (Scott, 2000; Wasserman & Faust, 1994). This conception might be appropriate for settings larger than a family, but still sufficiently compact that all participants interact at least indirectly with one another, such as a school classroom or an office workplace. Finally, a K-core is a subset of people in which every member is directly connected to at least K other members, and thus in which members interact with some minimum number of other members A B C D
  • 120. E F Q X Y Z All Maximal Complete Subgraphs Selected 2-Cliques All 2-Cores Figure 4. Types of Network Cliques. 734 Jennifer Watling Neal and Zachary P. Neal © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 (Scott, 2000; Wasserman & Faust, 1994). This conception is the most inclusive and thus might be appropriate for very large settings in which most participants do not directly interact with one another, but where social interaction with just a few others is sufficient for a sense of belonging, such as a school district or political party.
  • 121. Using network cliques to define settings is not a panacea for dealing with the complexity of ecological environments. Such an approach still requires researchers to consider several questions, including which conception of a clique is appropriate in a given context, and under what circumstances a network clique can be interpreted as a setting. However, for the goal of pushing EST from a purely conceptual model toward a robust method, we believe that these are the right questions for researchers to be asking. When seeking to understand the content and organization of the ecological environment surrounding a developing person, they focus attention on directly meas- urable features of the environment and allow ecological systems to emerge from the data rather than to be defined in advance based on a priori assumptions. Additionally, these questions highlight a path for the future development of EST as a method by suggesting parallels between the concept of an ecological environment and the vast empirical literature on clique analysis (e.g., Everett & Borgatti, 1998) and community detection (e.g., Fortunato, 2010). Summary and Conclusions In this article, we have sought to revisit Bronfenbrenner’s (1979) ecological systems theory, which is perhaps one of the most influential theories guiding developmental research. We contend that although EST is traditionally described using a nested
  • 122. systems metaphor, it is more usefully viewed as an overlapping configuration of interconnected ecological systems. Thus, we present an alternative ‘networked’ model of EST that defines ecological systems in terms of patterns of social interaction. This approach brings the relational perspective present in Bronfenbrenner’s (1945) earliest writing to EST and offers many benefits. Firstly, it reconceptualizes settings, drawing attention to social interactions as the building blocks of ecological systems. Secondly, it clarifies how ecological systems are related to one another, highlighting that they are not necessarily nested, but instead overlap in complex ways. Finally, it establishes the potential for a direct linkage between EST as a theory and social network analysis as a method, thereby paving the way for more precise operationalization and measure- ment for research adopting an EST perspective, but also for more theoretically informed applications of network analysis. As a new conceptual framework for under- standing what ecological systems are and how they relate to one another, we hope that the networked model of EST offers developmental researchers and others a useful way to think about ecological environments, and that this article represents merely an initial step in its further development. References Berndt, T. (1982). The features and effects of friendship in early adolescence. Child Develop-
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  • 130. Author Note Jennifer Watling Neal, Department of Psychology, Michigan State University; Zachary Neal, Department of Sociology, Michigan State University. The authors contributed equally in the conceptualization and writing of this article. Nested or Networked? 737 © 2013 John Wiley & Sons Ltd Social Development, 22, 4, 2013 INSTRUCTIONS FOR MODULE 5 DISCUSSION AND REFLECTION JOURNAL ESSAYS - ARE YOU READY? FOR MODULE 5 ESSAYS, WRITE ANSWERS TO THE DISCUSSION ESSAY PROMPT BELOW (500 WORDS) AND AN ANSWER TO THE REFLECTION JOURNAL ESSAY PROMPT BELOW (300 WORDS) 1) Propose a culturally and socially appropriate program for diversifying the microbiomes of children who attend pre- schools in Tempe or in a city of your choice (500 words). 2) WHAT'S INTERESTING in this module?Materials and Readings Read the following in preparation for the study questions assignment: · Learning Objective #1 Reading Assignment (attached) (attached) Learning Objectives of Module 5 By the end of this module, students will be able to: 1. Describe Bronfenbrenne's model of nested/networked
  • 131. relationships between ecology, environment and [biological] child development. 2. Describe the human microbiome. 3. Explain why microbiomes are the most important link between ecological, environmental, sociocultural factors and the biology of the self.Overview In this module, we will explore how goods for health become an integral part of the biology of individuals. We will learn about models of levels of interactions between systems that together form the ecology of an individual. Social interactions are the 'interactions' that matter most in humans since from birth to death, everything we do happens in the context of negotiating, reciprocating, giving or receiving goods and services between individuals.' In this module we will also learn about that social interactions at all ages are part and parcel of the microbial communities that reside in and on our bodies. We have learned a great deal in recent years about reciprocation between humans and our microbial friends, especially bacteria. In our gut, communities of bacteria supplement or altogether take over all sorts of biological functions that influence our metabolic, endocrinological and immune systems. The health of our microbiomes dictates the quality of our lives. When our microbiomes are disrupted by antibiotics, highly processed foods, lack of sleep, drug use, exposure to chemicals and other factors, their ability to perform functions that keep us healthy is compromised. It now appears that in developed countries with vast expanses of impervious surfaces, gut microbiomes are far less diverse than is the case in small scale societies that live in natural ecosystems with minimal built environments. These populations don't have epidemics of non-communicable diseases. Over 20 years of fieldwork among remote indigenous peoples of Latin America, I did not see a single case of asthma, allergies, breast cancer, Type 1 or Type 2 diabetes, Irritable Bowel Disease, Crohn's Disease or Cardiovascular Disease. Many other
  • 132. anthropologists who work in small scale societies have made similar observations. In the learning materials you will watch a presentation by Dr. Robert Knight that summarizes major research findings in recent studies of the microbiome. He suggests that the root cause of the co-occurring epidemics of non-communicable diseases over the past 30 years is a sudden change in gut microbiomes. This is an interesting hypothesis, and one of the most important take aways of this course.