evolution

1. History &Systems in Psychology
Submitted to:
 Sir Khurram
Submitted by:
 Warda Sattar(7207)
 Sohail Khawar(7209)
 Qurat ul Ain(7225)
 Asma Ali(7227)
Topic:
EVOLUTION & INDIVIDUAL DIFFERENCES
3RD
Semester, BS APPLIED PSYCHOLOGY
GOVERNMENT COLLEGE
UNIVERSITY
FAISALABAD

2. EVOLUTION BEFORE DARWIN
The idea that both the earth and living organisms change in some systematic way over
time goes back at least as far as the ancient Greeks. Those who refuse to believe in
Darwinian selection generally follow some version or other of Lamarkianism — a pre-
Darwinian form of evolutionary theory named after the brilliant biologist and founder
of invertebrate paleontology Jean Baptist Pierre Antoine de Monet, the Chevalier de
Lamarck (1744-1829).
JEAN BAPTIST LAMARCK
Early Life:
Born in Byzantine, Picardy, France on 1 August in
1744 to an aristocrat father, Jean-Baptist Lamarck was
the youngest of eleven children.
He initially followed in his family’s tradition and
became a soldier at the age of seventeen but an injury
forced him to retire after seven years in 1768.He died
in 1829
Theory of Evolution:
Although the name "Lamarck" is now associated with a discredited view of
evolution, the French biologist's notion that organisms inherit the traits acquired
during their parents' lifetime had common sense on its side. In fact, the
"inheritance of acquired characters" continued to have supporters well into the
20th century
 Lamarck believed that living things evolved in a continuously upward direction,
from dead matter, through simple to more complex forms, toward human
"perfection." Species didn't die out in extinctions, Lamarck claimed.
 Instead, they changed into other species. Since simple organisms exist
alongside complex "advanced" animals today, Lamarck thought they must be
continually created by spontaneous generation.
 This theory was called the Inheritance of acquired characteristics.
 Use & disuse: Individuals lose characteristics which they do not require and
develop characteristics which are useful.

3. According to Lamarck, organisms altered their behavior in response to
environmental change. Their changed behavior, in turn, modified their organs, and
their offspring inherited those "improved" structures. For example, giraffes
developed their elongated necks and front legs by generations of browsing on high
tree leaves. The exercise of stretching up to the leaves altered the neck and legs, and
their offspring inherited these acquired characteristics.
 However, through modern science we now know that in the vast majority of
cases this type of inheritance cannot occur.
Criticism:
 Lamarck's theory cannot account for all the observations made about life on
Earth. For instance, his theory implies that all organisms would gradually
become complex, and simple organisms disappear.
 It is now commonly accepted that Lamarck's ideas were wrong. For example,
simple organisms are still detected in all varieties of life, plus it is now
known that mutations can create variation such as neck length

4. HERBET SPENCER
Early life
Herbert Spencer was born in Derby, England on April 27, 1820. His father, William
George Spencer, was a rebel of the times and cultivated in Herbert an anti-
authoritarian attitude. George, as his father was known, was the founder of a school that
used unconventional teaching methods and was a contemporary of Erasmus Darwin,
grandfather of Charles. George focused Herbert's early education on science, and
simultaneously, he was introduced to philosophical thinking through George's
membership in the Derby
Philosophical Society. His uncle,
Thomas Spencer, contributed to
Herbert's education by instructing
him in mathematics, physics, Latin,
and free-trade and libertarian
political thinking. During the 1830s
Spencer worked as a civil engineer
while the railways were being
constructed throughout Britain, but
also spent time writing in radical
local journals. He died on December
8, 1903, Brighton, Sussex,
Career:
 English sociologist and philosopher, an early advocate of the theory
of evolution, who achieved an influential synthesis of knowledge, advocating
the preeminence of the individual over society and of science over religion.
 His magnum opus was The Synthetic Philosophy (1896),
a comprehensive work containing volumes on the principles
of biology, psychology, morality, and sociology.

5.  He is best remembered for his doctrine of social Darwinism, according to
which the principles of evolution, including natural selection, apply to human
societies, social classes, and individuals as well as to
biological species developing over geologic time. In Spencer’s day social
Darwinism was invoked to justify laissez-faire economics and the minimal state,
which were thought to best promote unfettered competition between individuals
and the gradual improvement of society through the “survival of the fittest,” a
term that Spencer himself introduced.
Major Publications
 Social Statics: The Conditions Essential to Human Happiness (1850)
 Education (1854)
 The Principles of Psychology (1855)
 The Principles of Sociology (1876-1896)
 The Data of Ethics (1884)
 The Man Versus the State (1884)
Theory of evolution
The most important contribution of Herbert Spencer is the theory of evolution. He
utilized the principles of physical and biological evolution in order to elaborate and
explain his theory of Social evolution.
1. In physical evolution, a movement is from indefinite incoherent situation to
definite and coherent situation. Besides, the underlying principles of physical
evolution are a movement from simple to complex and homogeneity to
heterogeneity.
2. In biological evolution only those creatures survive in the struggle for existence
who are able to make effective adjustment with changing circumstances. Herbert
Spencer utilized these two principles, physical and biological evolution in order
to explain social evolution.

6. Spencer’s-Bain Principle:
One of Bain's basic principles is immortalized as the Spencer-Bain principle: The
frequency or probability of a behavior rises if it is followed by a pleasurable event, and
decreases if it is followed by a painful event. This is, of course, the same principle that
the behaviorists would elaborate on a century later.
 To explain the differential persistence of various behaviors, Spencer
accepted Bain’s explanation of voluntary behavior. However, for
Spencer, the principle of contiguity alone was not adequate to explain
why some behaviors persist whereas others do not.
 In his explanation of how associations are formed, Spencer relied
heavily on the principle of contiguity. Environmental events that
occur both simultaneously or in close succession are recorded in the
brain and give rise to ideas of those events. Our highly complex
nervous system allows us to make an accurate neurophysiological
(and thus mental) recording of events in our environment, and this
ability is conducive to survival. Through the process of contiguity,
our ideas come to map environmental events.
Bain has an even larger role in the history of psychology. First, he is often given the
credit of having written two of the earliest textbooks in psychology -- The Senses and
the Intellect (1855) and Emotions and the Will (1859), both of which went through
many editions, and were used, for example, by William James. He also founded the
first English-language psychological journal, called Mind, in January of 1876. When
Darwin’s work appeared, Spencer merely shifted his emphasis from acquired
characteristics to natural selection. The concept of the survival of the fittest (a term
Spencer introduced in 1852 that was later adopted by Darwin) applied in either case.

7. Social Darwinism
Social Darwinism is a loose set of ideologies that emerged in the late 1800s in
which Charles Darwin’s theory of evolution by natural selection was used to
justify certain political, social, or economic views. Social Darwinists believe in
“survival of the fittest”—the idea that certain people become powerful in
society because they are innately better. Social Darwinism has been used to
justify imperialism, racism, eugenics and social inequality at various times
over the past century and a half.
The theory that human groups and races are subject to the same laws of natural
selection as Charles Darwin perceived in plants and animals in nature. According to the
theory, which was popular in the late 19th and early 20th centuries, the weak were
diminished and their cultures delimited while the strong grew in power and cultural
influence over the weak.
 Social Darwinists held that
the life of humans in society
was a struggle for existence
ruled by “survival of the
fittest,” a phrase proposed by
the British philosopher and
scientist Herbert Spencer.
 The humans in society, like
other animals in their natural
environment, struggle for
survival, and only the most
fit survive.
 According to Spencer, if the
principles of evolution are allowed to operate freely, all living organisms will
approximate perfection, including humans. The best policy for a government to
follow, then, is a laissez-faire policy that provides for free competition among its
citizens. Government programs designed to help the weak and poor would only
interfere with evolutionary principles and inhibit a society on its course toward
increased perfection. The following statement demonstrates how far Spencer
believed governments should follow a laissez-faire policy:
“If [individuals] are sufficiently complete [both physically and
mentally] to live, they do live, and it is well they should live. If they are not sufficiently
complete to live, they die, and it is best they should die” (1864, p. 415). Interestingly,

8. Spencer opposed only government programs to help the weak and poor. He supported
private charity because he believed it strengthened the character of the donors”
(Hofstadter, 1955)
Laissez-Faire Capitalism
After Darwin published his theories on biological evolution and natural
selection, Herbert Spencer drew further parallels between his economic theories
and Darwin’s scientific principles.
Spencer applied the idea of “survival of the fittest” to so-called laissez faire or
unrestrained capitalism during the Industrial Revolution, in which businesses
are allowed to operate with little regulation from the government.
Unlike Darwin, Spencer believed that people could genetically pass learned
qualities, such as frugality and morality, on to their children.
Spencer opposed any laws that helped workers, the poor, and those he deemed
genetically weak. Such laws, he argued, would go against the evolution of
civilization by delaying the extinction of the “unfit. Another prominent Social
Darwinist was American economist William Graham Sumner. He was an early
opponent of the welfare state. He viewed individual competition for property
and social status as a tool for eliminating the weak and immoral of the

9. population.
Social Darwinism refers to various theories that emerged in Western
Europe and North America in the 1870s that applied biological concepts of natural
selection and survival of the fittest to sociology, economics, and politics. Social
Darwinism posits that the strong see their wealth and power increase while the
weak see their wealth and power decrease. Various social Darwinist schools of
thought differ on which groups of people are the strong and which are the weak, and
also differ on the precise mechanisms that reward strength and punish weakness. Many
such views stress competition between individuals in laissez-faire capitalism, while
others
support authoritarianism, eugenics, racism, imperialism, fascism, Falangism,
Nazism, and struggle between national or racial groups.
Social Darwinism declined in popularity as a purportedly scientific concept following
the First World War, and was largely discredited by the end of the Second World War
partially due to its association with Nazism and partially due to a growing scientific
consensus that it was scientifically groundless.
Later theories that were categorized as social Darwinism were generally described as
such as a critique by their opponents; their proponents did not identify themselves by
such a label. Creationists have frequently maintained that social Darwinism—leading
to policies designed to reward the most competitive—is a logical consequence of
"Darwinism" (the theory of natural selection in biology).[9]
Biologists and historians
have stated that this is a fallacy of appeal to nature, since the theory of natural selection

10. is merely intended as a description of a biological phenomenon and should not be taken
to imply that this phenomenon is good or that it ought to be used as a moral guide
in human society.
Scholars debate the extent to which the various social Darwinist ideologies
reflect Charles Darwin's own views on human social and economic issues. His writings
have passages that can be interpreted as opposing aggressive individualism, while other
passages appear to promote it. Darwin's early evolutionary views and his opposition to
slavery ran counter to many of the claims that social Darwinists would eventually make
about the mental capabilities of the poor and colonial indigenes.
After the publication of On the Origin of Species in 1859, one strand of Darwins'
followers, led by Sir John Lubbock, argued that natural selection ceased to have any
noticeable effect on humans once organised societies had been formed.
 However, some scholars argue that
Darwin's view gradually changed
and came to incorporate views from
other theorists such as Herbert
Spencer.
 Spencer
published his Lamarckian evolutio
nary ideas about society before
Darwin first published his
hypothesis in 1859, and both
Spencer and Darwin promoted their
own conceptions of moral values.
 Spencer supported laissez-faire capitalism on the basis of his Lamarckian
belief that struggle for survival spurred self-improvement which could be
inherited.
 The theory was used to support laissez-faire capitalism and
political conservatism. Class stratification was justified on the basis of
“natural” inequalities among individuals, for the control of property was said to
be a correlate of superior and inherent moral attributes such as industriousness,
temperance, and frugality.
 Attempts to reform society through state intervention or other means would,
therefore, interfere with natural processes; unrestricted competition and defense
of the status quo were in accord with biological selection.
 The poor were the “unfit” and should not be aided; in the struggle for existence,
wealth was a sign of success.

11.  At the societal level, social Darwinism was used as a philosophical
rationalization for imperialist, colonialist, and racist policies, sustaining belief
in Anglo-Saxon or Aryan cultural and biological superiority.
It should not be concluded that Darwin was entirely unsympathetic toward applying
evolutionary principles to societies in the way Spencer had. In The Descent of Man
(1874/1998a), Darwin said,
“With savages, the weak in body or mind are soon eliminated; and those that survive
commonly exhibit a vigorous state of health. We civilized men, on the other hand, do
our utmost to check the process of elimination; we build asylums for the imbecile, the
maimed, and the sick; we institute poor-laws; and our medical men exert their utmost
skill to save the life of every one to the last moment. There is reason to believe that
vaccination has preserved thousands, who from a weak constitution would formerly
have succumbed to smallpox. Thus the weak members of civilized societies propagate
their kind. No one who has attended to the breeding of domestic animals will doubt that
this must be highly injurious to the race of man. Excepting in the case of man himself,
hardly any one is so ignorant as to allow his worst animals to breed’.
It was Spencer, be that as it may, who included such thinking and accentuated the
conviction that social orders, like people, would inexact flawlessness if normal powers
were permitted to work openly. Despite the fact that we have zeroed in on Spencer as a
transformative (and social) scholar, that is by no implies the constraint of his
commitments to the set of experiences of brain science. He was a popularizer of
positive science in the convention of Comte and of utilitarian morals in the custom of
Bentham. Notwithstanding the tradition of the Spencer–Bain standard, his 1855 reading
material, Principles of Psychology, was the most broadly peruse English language work
on brain research for quite a long time. William James utilized it in the main brain
research course he instructed at Harvard.
CHARLES DARWIN
Introduction:
Charles Darwin, in full Charles Robert Darwin,
(born February 12, 1809, Shrewsbury, Shropshire,
England—died April 19, 1882, Downe, Kent),
English naturalist whose scientific
theory of evolution by natural selection became the
foundation of modern evolutionary studies.

12. An affable country gentleman, Darwin at first shocked religious Victorian society by
suggesting that animals and humans shared a common ancestry. However, his
nonreligious biology appealed to the rising class of professional scientists, and by the
time of his death evolutionary imagery had spread through all of science, literature,
and politics. Darwin, himself an agnostic, was accorded the ultimate
British accolade of burial in Westminster Abbey, London.
Early Life And Education
 Darwin was the second son of society doctor Robert Waring Darwin and of
Susannah Wedgwood, daughter of the Unitarian pottery industrialist Josiah
Wedgwood.
 Darwin’s other grandfather, Erasmus Darwin, a freethinking physician and poet
fashionable before the French Revolution, was author of Zoonomia; or the Laws
of Organic Life (1794–96).
 Darwin’s mother died when he was eight, and he was cared for by his three
elder sisters. The boy stood in awe of his overbearing father,
whose astute medical observations taught him much about human psychology.
 But he hated the rote learning of Classics at the
traditional Anglican Shrewsbury School, where he studied between 1818 and
1825. Science was then considered dehumanizing in English public schools, and
for dabbling in chemistry Darwin was condemned by his headmaster (and
nicknamed “Gas” by his schoolmates).
 His father, considering the 16-year-old a wastrel interested only in game
shooting, sent him to study medicine at Edinburgh University in 1825. He was
taught to understand the chemistry of cooling rocks on the primitive Earth and
how to classify plants by the modern “natural system.” At the Edinburgh
Museum he was taught to stuff birds by John Edmonstone, a freed South
American slave, and to identify the rock strata and colonial flora and fauna.
 As he collected sea slugs and sea pens on nearby shores, he was accompanied
by Robert Edmond Grant, a radical evolutionist and disciple of the French
biologist Jean-Baptist Lamarck. An expert on sponges, Grant became
Darwin’s mentor, teaching him about the growth and relationships of primitive

13. marine invertebrates, which Grant believed held the key to unlocking the
mysteries surrounding the origin of more-complex creatures.
 Darwin, encouraged to tackle the larger questions of life through a study of
invertebrate zoology, made his own observations on the larval sea mat (Flustra)
and announced his findings at the student societies. The young Darwin learned
much in Edinburgh’s rich intellectual environment, but not medicine: he
loathed anatomy, and (pre-chloroform) surgery sickened him. His freethinking
father, shrewdly realizing that the church was a better calling for an aimless
naturalist, switched him to Christ’s College, Cambridge, in 1828.
 In a complete change of environment, Darwin was now educated as an Anglican
gentleman. He took his horse, indulged his drinking, shooting, and beetle-
collecting passions with other squires’ sons, and managed 10th place in the
Bachelor of Arts degree in 1831. Here he was shown the conservative side
of botany by a young professor, the Reverend John Stevens Henslow, while
that doyen of Providential design in the animal world, the Reverend Adam
Sedgwick, took Darwin to Wales in 1831 on a geologic field trip.
Darwin would not sail as a lowly surgeon-naturalist but as a self-financed gentleman
companion to the 26-year-old captain, Robert Fitzroy, an aristocrat who feared the
loneliness of command. Fitzroy’s was to be an imperial-evangelical voyage: he planned
to survey coastal Patagonia to facilitate British trade and return three “savages”
previously brought to England from Tierra del Fuego and Christianized. Darwin
equipped himself with weapons, books (Fitzroy gave him the first volume
of Principles of Geology, by Charles Lyell), and advice on preserving carcasses
from London Zoo’s experts. The Beagle sailed from England on December 27, 1831.
The Beagle Voyage
The circumnavigation of the globe would be the making of the 22-year-old Darwin.
Five years of physical hardship and mental rigour, imprisoned within a ship’s walls,
offset by wide-open opportunities in the Brazilian jungles and the Andes Mountains,
were to give Darwin a new seriousness. As a gentleman naturalist, he could leave the
ship for extended periods, pursuing his own interests. As a result, he spent only 18
months of the voyage aboard the ship.

14. The hardship was immediate: a tormenting seasickness. And so was his questioning:
on calm days Darwin’s plankton-filled townet left him wondering why beautiful
creatures teemed in the ocean’s vastness, where no human could appreciate them. On
the Cape Verde Islands (January 1832), the sailor saw bands of oyster shells running
through local rocks, suggesting that Lyell was right in his geologic speculations and that
the land was rising in places, falling in others.
At Salvador de Bahia(now Salvador), Brazil, the luxuriance of the rainforest left
Darwin’s mind in “a chaos of delight”. But that mind, with its Wedgwood-abolitionist
characteristics, was revolted by the local slavery. For Darwin, so often alone,
the tropical forests seemed to compensate for human evils: months were spent in Rio
de Janeiro amid that shimmering tropical splendour, full of “gaily-
coloured” flatworms, and the collector himself became “red-hot with Spiders.” But
nature had its own evils, and Darwin always remembered with a shudder the

15. parasitic ichneumon wasp, which stored caterpillars to be eaten alive by its grubs. He
would later consider that evidence against the beneficent design of nature.
On the River Plate (Río de la Plata) in July 1832, he found Montevideo, Uruguay, in
a state of rebellion and joined armed sailors to retake the rebel-held fort. At Bahía
Blanca, Argentina, gauchos told him of their extermination of the Pampas “Indians.”
Beneath the veneer of human civility, genocide seemed the rule on the frontier, a
conclusion reinforced by Darwin’s meeting with General Juan Manuel de Rosas and
his “villainous Banditti-like army,” in charge of eradicating the natives. For a
sensitive young man, fresh from Christ’s College, that was disturbing. His contact with
“untamed” humans on Tierra del Fuego in December 1832 unsettled him more. How
great, wrote Darwin, the “difference between savage & civilized man is.—It is
greater than between a wild & [a] domesticated animal.” God had evidently created
humans in a vast cultural range, and yet, judging by the Christianized savages aboard,
even the “lowest” races were capable of improvement. Darwin was tantalized, and
always he niggled for explanations
.

16. His fossil discoveries raised more questions. Darwin’s periodic trips over two years to
the cliffs at Bahía Blanca and farther south at Port St. Julian yielded huge bones of
extinct mammals. Darwin manhandled skulls, femurs, and armour plates back to the
ship—relics, he assumed, of rhinoceroses, mastodons, cow-sized armadillos, and
giant ground sloths (such as Megatherium). He unearthed a horse-sized mammal with
a long face like an anteater’s, and he returned from a 340-mile (550-km) ride
to Mercedes near the Uruguay River with a skull 28 inches (71 cm) long strapped to
his horse. Fossil extraction became a romance for Darwin. It pushed him into
thinking of the primeval world and what had caused those giant beasts to die out.
The land was evidently changing, rising; Darwin’s observations in the Andes
Mountains confirmed it. After
the Beagle surveyed the Falkland
Islands, and after Darwin had packed
away at Port Desire (Puerto
Deseado), Argentina, the partially
gnawed bones of a new species of
small rhea, the ship sailed up the
west coast of South
America to Valparaíso, Chile. Here
Darwin climbed 4,000 feet (1,200
metres) into the Andean foothills and
marveled at the forces that could
raise such mountains.
The forces themselves became tangible when he saw volcanic Mount Osorno erupt on
January 15, 1835. Then in Valdivia, Chile, on February 20, as he lay on a forest floor,
the ground shook: the violence of the earthquake and ensuing tidal wave was enough
to destroy the great city of Concepción, whose rubble Darwin walked through. But
what intrigued him was the seemingly insignificant: the local mussel beds, all dead,
were now lying above high tide.
The land had risen: Lyell, taking the uniformitarian position, had argued that
geologic formations were the result of steady cumulative forces of the sort we see
today. And Darwin had seen them. The continent was thrusting itself up, a few feet at a
time. He imagined the eons it had taken to raise the fossilized trees in sandstone (once
seashore mud) to 7,000 feet (2,100 metres), where he found them. Darwin began
thinking in terms of deep time. They left Peru on the circumnavigation home in
September 1835. First Darwin landed on the “frying hot” Galapagos Islands. Those

17. were volcanic prison islands, crawling with marine iguanas and giant tortoises.
(Darwin and the crew brought small tortoises aboard as pets, to join
their coatis from Peru.) Contrary to legend, those islands never provided Darwin’s
“eureka” moment. Although he noted that the mockingbirds differed on four islands and
tagged his specimens accordingly, he failed to label his other birds—what he thought
were wrens, “gross-beaks,” finches, and oriole-relatives—by island. Nor did Darwin
collect tortoise specimens, even though local prisoners believed that each island had its
distinct race.
The “home-sick heroes” returned via Tahiti, New Zealand, and Australia. By April
1836, when the Beagle made the Cocos (Keeling) Islands in the Indian Ocean—
Fitzroy’s brief being to see if coral reefs sat on mountain tops—Darwin already had his
theory of reef formation. He imagined (correctly) that those reefs grew on sinking
mountain rims. The delicate coral built up, compensating for the drowning land, so as
to remain within optimal heat and lighting conditions. At the Cape of Good Hope,
Darwin talked with the astronomer Sir John Herschel, possibly about Lyell’s gradual
geologic evolution and perhaps about how it entailed a new problem, the “mystery of
mysteries,” the simultaneous change of fossil life.

18. Thomas Malthus
Thomas Malthus lived from 1766 to 1834.
In 1798, he published the Principle of
Population where he made the observations
that the human race would be likely to
overproduce if the population size was not
kept under control.
Malthus then focused his studies on the
human race. His calculations and theories
produced an idea that the human population
would increase geometrically while the
food supply and natural resources would
only increase arithmetically. This is a
potential explanation for the predicted
poverty and famine. He concluded that as
more offspring are born, a more competitive nature would arise. As more offspring
come into the population, fewer resources will be available for the population. This
has the potential for competition between organisms for survival due to lack of
resources. This competitive nature would be necessary for survival of individuals within
a large population size unable to be supported by the environment. He believed that this
uncontrollable population size would eventually be the cause of famine and poverty
among humans. His reasoning behind this idea was divine intervention. He believed
that this would be the punishment for man if he became too lazy.
Malthus’ Principle of Population caused Darwin to rethink many issues while coming
up with his theory of natural selection.
 Malthus’ work made Darwin realize the importance of overpopulation and how
it was necessary to have variability in different populations. Darwin also used
Malthus’ ideas to use competition as well as the survival in numbers idea to
come up with his full idea of natural selection.
Selection of traits
In this struggle for existence, survival and reproduction do not come down to pure chance.
Darwin and Wallace both realized that if an animal has some trait that helps it to withstand
the elements or to breed more successfully, it may leave more offspring behind than others.
On average, the trait will become more common in the following generation, and the
generation after that.

19. As Darwin wrestled with natural selection he spent a great deal of time with pigeon
breeders, learning their methods. He found their work to be an analogy for evolution. A
pigeon breeder selected individual birds to reproduce in order to produce a neck ruffle.
Similarly, nature unconsciously "selects" individuals better suited to surviving their local
conditions. Given enough time, Darwin and Wallace argued, natural selection might produce
new types of body parts, from wings to eyes.
DARWIN AND WALLACE DEVELOP
SIMILAR THEORY
Darwin began formulating his theory of natural
selection in the late 1830s but he went on working
quietly on it for twenty years. He wanted to amass a
wealth of evidence before publicly presenting his
idea. During those years he corresponded briefly with
Wallace (right), who was exploring the wildlife of
South America and Asia. Wallace supplied Darwin
with birds for his studies and decided to seek
Darwin's help in publishing his own ideas on
evolution. He sent Darwin his theory in 1858, which,
to Darwin's shock, nearly replicated Darwin's own.
Charles Lyell and Joseph Dalton Hooker arranged for both
Darwin's and Wallace's theories to be presented to a meeting of
the Linnaean Society in 1858. Darwin had been working on a
major book on evolution and used that to develop On the
Origins of Species, which was published in 1859. Wallace, on
the other hand, continued his travels and focused his study on the
importance of biogeography.
The book was not only a best seller but also one of the most influential scientific books of all
time. Yet it took time for its full argument to take hold. Within a few decades, most scientists
accepted that evolution and the descent of species from common ancestors were real. But
natural selection had a harder time finding acceptance. In the late 1800s many scientists who
called themselves Darwinists actually preferred a Lamarckian explanation for the way life
changed over time. It would take the discovery of genes and mutations in the twentieth
century to make natural selection not just attractive as an explanation, but unavoidable.

20. Darwin's Theory of Evolution
The theory of evolution by natural selection, first formulated in Darwin's book "On the
Origin of Species" in 1859, is the process by which organisms change over time as a
result of changes in heritable physical or behavioral traits. Changes that allow an
organism to better adapt to its environment will help it survive and have more offspring.
Evolution by natural selection is one of the best substantiated theories in the history of
science, supported by evidence from a wide variety of scientific disciplines, including
paleontology, geology, genetics and developmental biology.
The theory has two main points "All life on Earth is connected and related to each
other," and this diversity of life is a product of "modifications of populations by natural
selection, where some traits were favored in and environment over others,"
More simply put, the theory can be described as "descent with modification," said Briana
Pobiner, an anthropologist and educator at the Smithsonian Institution National Museum of
Natural History in Washington, D.C., who specializes in the study of human origins. The
theory is sometimes described as "survival of the fittest," but that can be misleading,
Pobiner said. Here, "fitness" refers not to an organism's strength or athletic ability, but
rather the ability to survive and reproduce. Many people may have trouble finding a mate
because of rapidly changing social technological advances that are evolving faster than
humans. "Nearly 1 in 2 individuals faces considerable difficulties in the domain of mating,"

21. In most cases, these difficulties are not due to something wrong or broken, but due to people
living in an environment which is very different from the environment they evolved to
function in.
Natural selection
Natural selection can change a species in small ways, causing a population to change color
or size over the course of several generations. This is called "microevolution."But natural
selection is also capable of much more. Given enough time and enough accumulated changes,
natural selection can create entirely new species, known as "macroevolution." It can turn
dinosaurs into birds, amphibious mammals into whales and the ancestors of apes into
humans.
Take the example of whales — using evolution as their guide and knowing how natural
selection works, biologists knew that the transition of early whales from land to water
occurred in a series of predictable steps.
The evolution of the blowhole, for example, might have happened in the following way:
 Random genetic changes resulted in at least one whale having its nostrils placed
farther back on its head. Those animals with this adaptation would have been better
suited to a marine lifestyle, since they would not have had to completely surface to
breathe.
 Such animals would have been more successful and had more offspring. In later
generations, more genetic changes occurred, moving the nose farther back on the
head.
 Other body parts of early whales also changed. Front legs became flippers. Back legs
disappeared. Their bodies became more streamlined and they developed tail flukes to
better propel themselves through water.

22.  Darwin also described a form of natural selection that depends on an organism's
success at attracting a mate, a process known as sexual selection. The colorful
plumage of peacocks and the antlers of male deer are both examples of traits that
evolved under this type of selection. But Darwin wasn't the first or only scientist to
develop a theory of evolution. The French biologist Jean-Baptist Lamarck came up
with the idea that an organism could pass on traits to its offspring, though he was
wrong about some of the details. Around the same time as Darwin, British biologist
Alfred Russel Wallace independently came up with the theory of evolution by natural
selection.
Modern understanding
Darwin didn't know anything about genetics, Pobiner said. "He observed the pattern of
evolution, but he didn't really know about the mechanism." That came later, with the
discovery of how genes encode different biological or behavioral traits, and how genes are
passed down from parents to offspring. The incorporation of genetics and Darwin's theory is
known as "modern evolutionary synthesis."
 The physical and behavioral changes that make natural selection possible happen at
the level of DNA and genes. Such changes are called mutations. "Mutations are
basically the raw material on which evolution acts," Pobiner said.
 Mutations can be caused by random errors in DNA replication or repair, or by
chemical or radiation damage. Most times, mutations are either harmful or neutral, but
in rare instances, a mutation might prove beneficial to the organism. If so, it will
become more prevalent in the next generation and spread throughout the population.
 In this way, natural selection guides the evolutionary process, preserving and adding
up the beneficial mutations and rejecting the bad ones. "Mutations are random, but
selection for them is not random," Pobiner said.
 But natural selection isn't the only mechanism by which organisms evolve. For
example, genes can be transferred from one population to another when
organisms migrate or immigrate, a process known as gene flow. And the
frequency of certain genes can also change at random, which is called genetic
drift.
A wealth of evidence
Even though scientists could predict what early whales should look like, they lacked the
fossil evidence to back up their claim. Creationists took this absence as proof that evolution

23. didn't occur. They mocked the idea that there could have ever been such a thing as a walking
whale. But since the early 1990s, that's exactly what scientists have been finding.
 The critical piece of evidence came in 1994, when paleontologists found the fossilized
remains of Ambulocetus natans, an animal whose name literally means "swimming-
walking whale." Its forelimbs had fingers and small hooves but its hind feet were
enormous given its size. It was clearly adapted for swimming, but it was also capable
of moving clumsily on land, much like a seal.
 When it swam, the ancient creature moved like an otter, pushing back with its hind feet
and undulating its spine and tail.
 Modern whales propel themselves through the water with powerful beats of their
horizontal tail flukes, but Ambulocetus still had a whip-like tail and had to use its legs
to provide most of the propulsive force needed to move through water.
 In recent years, more and more of these transitional species, or "missing links," have
been discovered, lending further support to Darwin's theory, Richmond said.
 Fossil "links" have also been found to support human evolution. In early 2018, a
fossilized jaw and teeth found that are estimated to be up to 194,000 years old,
making them at least 50,000 years older than modern human fossils previously
found outside Africa. This finding provides another clue to how humans have evolved.
In the theory of natural selection, organisms produce more offspring than are able to
survive in their environment. Those that are better physically equipped to survive, grow to
maturity, and reproduce. Those that are lacking in such fitness, on the other hand, either do
not reach an age when they can reproduce or produce fewer offspring than their counterparts.
 This means that if environment changes, the traits that enhance survival in that
environment will also gradually change, or evolve.
 Natural selection was such a powerful idea in explaining the evolution of life that it
became established as a scientific theory.
 Biologists have since observed numerous examples of natural selection influencing
evolution. Today, it is known to be just one of several mechanisms by which life
evolves. For example, a phenomenon known as genetic drift can also cause species to
evolve.
 In genetic drift, some organisms purely by chance produce more offspring than would
be expected. Those organisms are not necessarily the fittest of their species, but it is

24. their genes that get passed on to the next generation.
Human Evolution
In On the Origin of Species, Darwin said very little about humans, but later, in The Descent
of Man he made his case that humans are also the product of evolution. Both humans
and the great apes, he said, descended from a common, distant primate ancestor. Of
Darwin’s books, the one most directly related to psychology is The Expression of the
Emotions in Man and Animals (1872/1998b), in which he argued that human emotions are
remnants of animal emotions that had once been necessary for survival. In the distant past,
only those organisms capable of such things as biting and clawing survived and reproduced.
Somewhat later, perhaps, simply baring of teeth or snarling were enough to discourage an
aggressor and therefore facilitated survival. Although no longer as functional in modern
society, the emotions that were originally associated with attack or defense are still part of
our biological makeup, as can be seen in human reactions under extreme conditions.
 Darwin also noted that the expression of human emotions is culturally universal.
 By observing the facial characteristics of a person anywhere on earth, one could
determine if that person were experiencing joy, grief, anger, sadness, or some other
emotion. For an excellent summary of Darwin’s theory of emotions and a discussion
of its current relevance, see Ekman (1998).

25. Darwin’s direct comparison of humans with other animals in The Expression of the
Emotions, along with his forceful assertion that humans differ from other animals only in
degree, launched modern comparative and animal psychology. It became clear that much
could be learned about humans by studying nonhuman animals. Darwin also influenced
subsequent psychology when he carefully observed the development of his first son, William
(born 1839). He noted when various reflexes and motor abilities first appeared, as well as
various learning abilities. Although he delayed publication of his observations until William
was 37, Darwin’s report (1877) was among the first examples of what was later called
developmental psychology.
Darwin’s Influences
Darwin changed the traditional view of human nature and with it changed the history of
philosophy and psychology. Many of the topics dismissed by Titchener because they
did not represent pure experimental psychology were encouraged by Darwin’s theory.
Darwinian influence:
 Developmental psychology,
 Animal psychology,
 Comparative psychology,
 Psychobiology,
 Learning,
 Tests and measurements,
 Emotions,
 Behavioral genetics,
 Abnormal psychology,
and a variety of other topics under the heading of applied psychology.
In general, Darwin stimulated interest in the study of individual differences and
showed that studying behavior is at least as important as studying the mind.
Darwin’s influence, however, was not entirely positive. He entertained a number of
beliefs now considered highly questionable or mistaken, such as the following:
■ Contemporary primitive people are the link between primates and modern humans
(that is, Europeans) and are therefore, inferior.

26. ■ Women are intellectually inferior to men. Alland) says, “Darwin at his worst is
Darwin on women” For examples of Darwin’s beliefs concerning the intellectual
inferiority of women, see Darwin.
■ Long practiced habits become heritable instincts; in other words, in explaining
cultural differences among humans, Darwin accepted Lamarckian theory.
By modifying Darwin’s definition of fitness from the survival and reproductive success
of the individual (Darwin’s definition) to the perpetuation of one’s genes, sociobiology
can account for a wide array of human social behavior. Because one’s kin carries one’s
genes, helping them survive and reproduce becomes an effective way of perpetuating
one’s genes. Armed with this conception of inclusive fitness, sociobiologists attempt
to explain such things as love, altruism, warfare, religion, morality, mating systems,
mate-selection strategies, child-rearing strategies, xenophobia, aggressive
behavior, nepotism, and indoctrinability. What Wilson called sociobiology is now
called evolutionary psychology and is extremely popular in contemporary
psychology.

27. SIR FRANCIS GALTON
Francis Galton was an explorer and anthropologist
known for his studies in eugenics and human
intelligence. As a child, Galton rejected conventional
methods of teaching, and he began studying medicine
in his teens. He soon embraced a passion for travel
with the help from a sufficient fortune left to him
from his father. A cousin of Charles Darwin, Galton
researched the implications of Darwin’s theory of
evolution, focusing on human genius and selective
mating.
Early Life
Francis Galton spent much of his life dedicated to research and critical inquiries into
several different subject areas, from exploration to eugenics to weather to fingerprints.
He was born on February 16, 1822, and grew up in a wealthy family near
Birmingham, England. At an early age, he began to show great intellectual promise.
At first, Galton planned to become a doctor. He studied medicine at Birmingham's
General Hospital and at King's College in London in the late 1830s. But he abandoned
this idea and went on to study mathematics at Cambridge University. After his father's
death in 1844, Galton received a substantial inheritance. This inheritance enabled him
to pursue whatever topic piqued his curiosity. And he soon decided that it was time to
explore more distant shores.
Exploration and Accomplishments
In the mid-1840s, Galton made his first trip to the Middle East and Africa. He went to
Egypt and traveled down the Nile River to the Sudan, among other destinations in the
area. His travels inspired him to undertake an exploration of southern Africa. In 1850,
Galton joined the Royal Geographical Society and soon set off on his journey, with the
society's approval. He initially planned to travel from an area known as Damaraland to
Lake Ngami, but he ended up traveling through a Southwestern section called
Ovamboland.

28. Galton's maps and observations and descriptions of the native peoples of these regions
brought him great acclaim, including a gold medal from the Royal Geographical
Society. He published on a book on his exploration, entitled Tropical South
Africa (1853). Two years later, Galton offered his advice for other would-be explorers
in The Art of Travel: Or, Shifts and Contrivances Available in Wild Countries (1855).
Married in 1853 to Louisa Jane Butler, Galton ended his explorations for other
scientific pursuits. He became interested in weather and created the first weather map,
showing different climate conditions across a geographical area. In 1863, he published a
book on the subject, called Meteorgraphica, or Methods of Mapping the Weather. To
further illustrate Galton’s passion for measurement, here are a few of his other
endeavors:
■ In his effort to measure and predict the weather, he invented the weather map and was
the first to use the terms highs, lows, and fronts.
■ He was the first to suggest that fingerprints could be used for personal identification a
procedure later adopted by Scotland Yard.
■ Initially intended as another tool for criminologists, Galton studied composite
portraiture or the creation of new faces based on combining multiple photographs. He
discovered that the more images used, the more attractive the composite face.
■ He tried to determine which country had the most beautiful women.
■ He measured the degree of boredom at scientific lectures.
■ He attempted to determine the effectiveness of prayer (he found it ineffective)
Strongly influenced by Darwin's The Origin of Species (1859), Galton developed his
own theories on inherited traits.
 He studied identical twins and worked on the first intelligence test in his
exploration of the roles of "nature and nurture" a phrase created by Galton in
human attributes.

29.  According to some sources, Galton also coined the term "eugenics," a
controversial field of study about selective breeding in humans to produce
preferred traits.
Fingerprints
During his anthropological studies, Galton noticed a great degree of individuality
amongst fingerprints. He was the first to comprehensively examine fingerprints and
scientifically determine that they could be used for purposes of identification. In his
anthropological laboratories, he collected over 8,000 sets of fingerprints and published
many scholarly papers about fingerprint classification, which was later adapted
by E.R. Henry. This research was the foundation for use of fingerprints for forensic
purposes in crimes.
Measuring Intelligence
One of the topics that Francis Galton was best known for was his work
with intelligence. He believed that many aspects of human nature, including
intelligence, could be measured scientifically. In a time before I.Q. tests, Galton
attempted to measure intelligence through reaction time tests. For example, the faster
someone could register and identify a sound, the more intelligent that person was.
Eugenics
Galton's eugenics was a program to artificially produce a better human race through
regulating marriage and thus procreation. Galton put particular emphasis on
"positive eugenics", aimed at encouraging the physically and mentally superior
members of the population to choose partners with similar traits. Galton’s conclusion
raised a fascinating possibility: selective breeding. If intelligence is inherited, could not
the general intelligence of a people be improved by encouraging the mating of bright
people?
After reading Hereditary Genius, Darwin wrote to his cousin: “You have made a
convert of an opponent in one sense, for I have always maintained that excepting fools,
men did not differ much in intellect only in zeal and hard work” (Pearson, 1914, p.
Darwin gave credit to Galton for calling to his attention the fact that allowing weak
members of a society to breed weakens the human stock. Thus, as we have noted,
Darwin was not entirely adverse to what was called social Darwinism nor, as we have
seen, was he entirely opposed to the idea of eugenics. The very mention of eugenics is
often considered distasteful given its association with Nazi atrocities and various

30. modern-day ethnic “cleansings.” Nevertheless, as Galton observed animals had long
been selectively bred, and almost every culture engaged in some sort of eugenics.
Nature VS Nurture Controversery
Francis Galton is credited with first envisioning a science of nature versus nurture. For
Galton, the question of nature versus nurture was of interest in part because it
contributed to understanding where human traits of interest came from.
 To determine whether heredity or environmental exposures contributed more
to traits like criminality or intelligence, Galton developed several
methodologies to answer the question.
 First, he made use of family studies; in Hereditary Genius, Galton collected data
on generations of judges, military commanders, and scientists and concluded that
these eminent figures were confined to a relatively small number of families.
Galton also pioneered the use of twin studies, examining the results of identical
twins reared together or apart and comparing twins to other siblings.

Galton was also interested in the nature/nurture question because he thought an answer
to it could be used to guide interventions in the world. For Galton, the interventions
came in the form of eugenics—a “science which deals with all the influences that
improve the inborn qualities of race.”
 Galton believed that his family studies and twin studies pointed to nature
trumping nurture when it came to traits such as criminality and intelligence, and
so he envisioned eugenics as a scientifically-guided social program which would
encourage more intelligent and less criminal people to marry and breed more,

31. while less intelligent and more criminal people would be encouraged to marry
and breed less.
Words and Images
In Inquiries, Galton devised psychology’s first word association test. He went through
the 75 words on four different occasions, randomizing the words each time. Three
things struck Galton about this study. First, responses to stimulus words tended to be
constant; he very often gave the same response to a word all
four times he experienced it. Whether Galton directly influenced Freud is not known,
but Galton’s work with word association anticipated two aspects
of psychoanalysis:
1. The use of free association
2. The recognition of unconscious motivation.
Mental Imagery
Galton was also among the first, if not the first, to study imagery. In Inquiries he
reported the results of asking people to imagine the scene as they had sat down to
breakfast. He found that the ability to imagine was essentially normally distributed,
with some individuals almost totally incapable of imagery and others having the ability
to imagine the breakfast scene in great detail. Galton was amazed to find that many of
his scientist friends had virtually no ability to form images.
Anthropometry
Galton measured head size, arm span, standing height, sitting height, length of the
middle finger, weight, strength of hand squeeze (measured by a dynamometer),
breathing capacity, visual acuity, auditory acuity, reaction time to visual and
auditory stimuli, the highest detectable auditory tone, and speed of blow (the time
it takes for a person to punch a pad). Some of these measures were included because
Galton believed sensory acuity to be related to intelligence, and for that reason,
Galton’s anthropometric laboratory can be viewed as an effort to measure intelligence,
or even the beginning of the mental testing movement in psychology.In 1888 Galton set
up a similar laboratory in the science galleries of the South Kensington Museum, and it
operated for several years. For keeping a methodological register of the principal
measurements of each person, of
which he may at any future time obtain a copy under reasonable restrictions. And for a
smaller fee a person could be measured again at another time.

32.  Among the many things that Galton was interested in examining were testretest
relationships, gender differences on various measurements, intercorrelations
among various measurements, relationships of various measurements to
socioeconomic status, and family resemblances among various measurements.
 Because Galton’s incredible amount of data existed long before there were
computers or even calculators, much of it went unanalyzed at the time. (1985)
reported the results of Galton’s own analyses, the results of analyses of Galton’s
data done by researchers after him, and their own considerations of Galton’s data.
The Concept of Correlation
In 1888 Galton published an article titled “Co-Relations and Their Measurement,
Chiefly from Anthropometric Data,” and in 1889 he published a book titled Natural
Inheritance. Both works describe the concepts of correlation and regression. Galton
(1888) defined correlation, as follows:
Two variable organs are said to be co-related when the variation on one is
accompanied on the average by more or less variation of the other, and in the
same direction.
In a definition of correlation, the word tend is very important. Even in the above
quotation, Galton said that those with long arms usually have long legs. After planting
peas of varying sizes and measuring the size of their offspring, Galton observed that
very large peas tended to have offspring not quite as large as they were and that very
small peas tended to have offspring not quite as small as themselves. He called this
phenomenon regression toward the mean, something he also found when he correlated
heights of children with heights of their parents. In fact, Galton found regression
whenever he correlated inherited characteristics. Earlier, Galton had observed that
eminent individuals only tended to have eminent offspring.
 It was Karl Pearson (1857–1936) who devised a formula that produced a
mathematical expression of the strength of a relationship. Pearson’s formula
produces the now familiar coefficient of correlation (r).
Galton’s Contributions to Psychology
Galton's study of human abilities ultimately led to the foundation of
differential psychology and the formulation of the first mental tests. He was
interested in measuring humans in every way possible. His psychological studies

33. also embraced mental differences in visualization, and he was the first to identify
and study "number forms", now called "synaesthesia". He also invented the word-
association test, and investigated the operations of the sub-conscious mind.
Final Years and Death
Galton spent much of his life studying heredity and eugenics, and he later thought that a
person's fingerprints might be a part of human genetic puzzle. He thought that these
prints might provide information on differences between people, from race to moral
character to intelligence. While he never made any discoveries in this area, Galton
established a fingerprint classification system that is still in use today.
In 1908, Galton published his autobiography. He received a knighthood from King
Edward the following year. Galton died on January 17, 1911, in Haslemere, England, at
the age of 88. In his will, he donated funds for a professorship in eugenics to University
College London.
James McKeen Cattell
James McKeen Cattell was the first
psychology professor in the United States,
teaching at the University of Pennsylvania.
During those early days, psychology was
often regarded as a lesser science and was
often even viewed as a pseudoscience.
Cattell is credited with helping established
psychology's legitimacy as a science thanks
to his focus on quantitative methods. He
was also the founder and editor of a number
of scientific journals including The
Psychological Review.
Birth and Death
 James McKeen Cattell was born May 25, 1860, in Easton, Pennsylvania.
 He died January 20, 1944.

34. Early Life
James McKeen Cattell was the oldest child born to a wealthy family in Pennsylvania.
His father, William, was a Presbyterian minister who later became the president of
Lafayette College. His uncle was Alexander Gilmore Cattell, a U.S. Senator for New
Jersey. Cattell attended Lafayette College starting at age 16 where he studied English
literature. He later graduated with an M.A. degree.
After visiting Germany for graduate study, Cattell met Wilhelm Wundt and developed
an interest in psychology. After a brief stint studying at John Hopkins University,
Cattell returned to Germany to serve as Wundt's assistant. Cattell went on to publish the
first psychology dissertation.
Career
Cattell was awarded his Ph.D. in 1886 and became a lecturer at the University of
Cambridge. He returned to the United States to teach psychology at the University of
Pennsylvania and later at Columbia University. In 1895, he became the President of
the American Psychological Association.
Cattell was later fired from his position at Columbia over his public opposition to U.S.
involvement in World War I. He later won a lawsuit against the university and, with the
money he was awarded by courts, founded the Psychological Corporation with Edward
L. Thorndike and Robert S. Woodworth. The corporation was one of the largest
creators and administrators of mental tests.
Contributions to Psychology
Early in its history, psychology was often viewed as a lesser science or even a
pseudoscience. As Cattell explained in his 1895 APA address:
"In the struggle for existence that obtains among the sciences psychology is continually
gaining ground.... The academic growth of psychology in America during the past few
years is almost without precedent.... Psychology is a required subject in the
undergraduate curriculum ..., and among university courses psychology now rivals the
other leading sciences in the number of students attracted and in the amount of original
work accomplished."
Major Contributions

35. James McKeen Cattell is an important figure in psychology and the study of human
intelligence for several reasons. While at Leipzig, working under Wundt, he was the
first American to publish a dissertation, Psychometric Investigation. After his return
from Europe, perhaps no other person contributed more to the strengthening of
American psychology in the late 1890s and early 1900s.
 He was involved with the formation of many major publications, including co-
founder and co-editor of The Psychological Review (1894-1903), editor and
publisher of the Journal of Science (1894-1944 ), founder of the
Psychological Corporation (1921), and founder of the Science Press (1923),
among many others.
 He was similarly involved with major professional organizations, including the
American Psychological Association, the American Association of University
Professors, and the American Association for the Advancement of Science.
 One of Cattell's goals was to have psychology viewed as a science on par
with the physical and life sciences. As he noted in his presidential address to the
American Psychological Association,
 In the struggle for existence that obtains among the sciences psychology is
continually gaining ground. He academic growth of psychology in American
during the past few years is almost without precedent.
Psychology is a required subject in the undergraduate curriculum ..., and among
university courses psychology now rivals the other leading sciences in the number
of students attracted and in the amount of original work accomplished.
In that address, Cattell provides additional evidence of the growth of psychology as a
science, including a favorable comparison of the major academic journals (e.g., all
three general science journals at the time published psychological studies, and the
field boasted two specialty journals compared to three for mathematics, two for
chemistry, geology, and botany, and one for physics), the historical basis of
psychology.
Cattell believed that the continued growth of psychology was dependent on the
field's acceptance of quantitative methods similar to those used in other sciences. This
belief was somewhat controversial:
 Although psychological laboratories were flourishing in the United States, the
philosophical underpinnings of psychology led some to question the validity and,
indeed, the necessity of psychological measurements. But Cattell felt that
experimental approaches to psychology, especially those involving "psycho-

36. physical" measurement, were critical to the rise and continued success of
academic psychology.
Cattell's approach to psychophysical measurement (often referred to as
anthropometric testing) was influenced by his brief work with Francis Galton in
England before Cattell returned to the United States from his European studies.
Although it is widely believed that Cattell's goal was to measure intelligence or a
similar construct with these tests, his goals appear to have been related for the
most part to his goal of strengthening psychology's scientific credentials
As Cattell's thinking about these psychophysical measures developed, he appears to
have viewed the data as evidence of a unitary intellect. This view was somewhat
controversial, especially in light of the dissertation research of Clark Wissler, one of
Cattell's laboratory assistants. Wissler found little evidence of general intellectual
ability, since the correlations of the various psychphysical tests with each other and
with external criteria (e.g., grades) were low. Controversy exists about both the quality
of Wissler's research and both Wissler's and Cattell's reaction to it, but Wissler’s work
is often considered, in the words of Sternberg (1990), the "coup de grace" for
anthropometric testing.
Cattell's use of statistical methods and quantification of data helped in the
development of American psychology as an experimental science. He was one of the
first psychologists in America to stress the importance of quantification, ranking, and
ratings. An outgrowth of this work, his experimentation with psychophysical testing,
was influential in the popularization of mental testing within the psychological
laboratory. However, anthropometric testing in general became controversial with the
publication of Wissler's work.
Measuring Intelligence
 As psychologists investigated different areas of human behavior, they began to
look for ways in which the science could be used to help people. The first modern
intelligence test was devised by Alfred Binet in 1905 at the request of the French
education authorities.
 In 1881, the French Government introduced compulsory schooling for all
children.

37. This meant that slow learners, who had originally been kept at home, now had to attend
school. Binet devised a test which measured ability and considered that age of the child
being tested. He devised the concept of mental age which is the individual’s mental
development in relation to others
Individual intelligence test
 Mental Age
 Intelligence Quotient
 Normal distribution

38. An individual’s level of mental development relative to
others
IQ= Mental Age/ Chronological age × 100
 A Symmetrical distribution
 Majority of the scores falling in the middle
 Few scores in the extreme
The Binet Test

39. The Normal Curve and Binet IQ
Scores

40. Charles spearman
 Charles Spearman postulated two types of intelligence that account for test
scores:
 general intelligence or g
 special intelligences, or s,
 which are the specific skills and knowledge needed to answer the questions
on a particular test.
 G Factor Developed the g factor, which stood for general intelligence, He
believed that this single g factor was responsible for each type of mental
ability.
 Spearman did not believe in separate intelligences like musical or analytical, but
just one overall general intelligence.
 If you received a score of 120 on an IQ test then this would be your indicative of
your g factor. Since your g factor is high, then no matter what profession or career
you chose you would be successful.

42. Discounting Spearman’s Theory
Most people know a person who may be intelligent in math, but struggle
with verbal abilities. In other words, even people that are intelligent in one
area may struggle in another area, which proved Spearman’s theory wrong
Cyril Burt
“Spearman’s successor”
His life’s work was fixated on the notion that
intelligence is heritable. Gould says: Burt’s
conclusions were distorted, namely his proof that
intelligence is innate. The 1909 study is logically
flawed, as well as statistically flawed

43. Burt’s Extension of Spearman’s Theory
 Charles Spearman’s two-factor theory, the g and s, was created to study
and generalize human-societal relationships. Cyril Burt wished to use this
theory of his predecessor’s to rank and sort pupils because they “had to be
guided toward professions by identifying strengths and weaknesses in
more specific areas” Thus, Burt created the four-factor theory.
 G—the first component of correlation found in mental testing Group
Factors—subordinate to g, but above ss—attributes of a single trait
measured on all occasions Accidental Factors—attributes of a single trait
measured on one occasion Group factors “cover different abilities
according to their form of content” .
Intelligence Test In United States
Henry Herbert Goddard
 Born August 14, 1866
 PhD in psychology from Clark University Director of Research at the
Training School for Feeble-minded Girls and Boys
 Translated the Binet-Simon intelligence scale into English
 Established the first laboratory for the psychological study of mentally
retarded persons Helped
 draft the first American law mandating special education
 Was a proponent of the hereditarian position

44. Goddard’s view on intelligence was derived from Mendelian genetics
• Believed that feeblemindedness was caused by the transmission of a single
recessive gene
• Believed that those who were feebleminded were inferior
 Goddard concluded that a variety of mental traits were hereditary and
that society should limit reproduction by people possessing these traits
 Goddard argued that society should keep feebleminded people from
having children, either through institutional isolation or sexual
The father of intelligence

45. sterilization. As a result of its seductive mix of science and ideology,
Goddard’s book became a favorite among eugenicists. As such,
Goddard’s views were part of a dark chapter in American history.
 Goddard was a far more complex and nuanced individual than this
brief account implies. His papers, housed at the Archives of the History
of American Psychology at the University of Akron
LEWIS MADISON TERMAN
 Lewis Madison Terman was
an eminent American
psychologist who is most
noted for his seminal studies
of children of high
intelligence
 Terman defined intelligence as
“the ability to carry out abstract
thinking” and used the label IQ
or Intelligence Quotient.
 Invented the Stanford-Binet IQ
Test
 He revised Binet’s test to work for large numbers of people in an attempt
to measure what he thought was inherited intelligence.
 Worked with Maslow at U Wisconsin.

47. Leta Stetter Hollingworth
(1886–1939)
Hollingworth attained her bachelor’s degree from the University of Nebraska.
Earning his PhD under Cattell at Columbia, he wrote 25 books on
psychological topics and served as president of the American Psychological
Association in 1927. She decided to enroll as a graduate student at Columbia
University, where she took courses from Edward L. Thorndike, who became
her advisor. It was through Thorndike that she developed an interest in
psychological testing. Hollingworth also challenged the widely accepted beliefs
that intelligence is largely inherited and that women are intellectually inferior
to males. At the time, Thorndike was among those who shared these beliefs.
Hollingworth (1940) believed that women reach positions of prominence less
often than males not because of intellectual inferiority but because of the social
roles assigned to them. After receiving her master’s degree in 1913,
Hollingworth worked for a while as a clinical psychologist at the New York
City Clearing-House for Mental Defectives, where she administered Binet tests.
She then worked at Bellevue Hospital as a clinical psychologist until attaining
her doctorate from Columbia University in 1916. Soon thereafter she became a
professor of education at Teachers College, Columbia University.
Hollingworth next concentrated her attention on the education of gifted
children. She observed that simply classifying a child as gifted is not enough.
Leta Stetter Hollingworth was primarily concerned with developing educational
strategies that would ensure the developmental well-being of gifted students. In
1926 she published Gifted Children, which became the standard text in schools
of education for many years, and Children above 180 I.Q. was published
posthumously in 1942.

48. Robert M. Yerkes (1876–1956)
Robert M. Yerkes (1876–1956) was the firstborn son from a rural Pennsylvania
farm family. He was disillusioned by farm life, however, and dreamed of
becoming a medical doctor. Yerkes went to Harvard, where he became
interested in animal behaviour. Obtaining his doctorate in 1902, he remained at
Harvard as a faculty member. With his friend John B. Watson, who was then
at Johns Hopkins University, Yerkes established comparative psychology in
the United States. In recognition of his ultimate success, Yerkes was elected
president of the APA in 1917. In 1912, he took the job of director of
psychological research in hospital and used Binet-Simon scale for clinical
diagnosis.
Yerkes’s contribution to intelligence testing was his suggestion that all
individuals be given all items on the Binet– Simon test and be given points for
the items passed. Thus, a person’s score would be in terms of total points
earned instead of an IQ. This removes age as a factor in scoring. The traditional
procedure followed in administering the Binet– Simon scale was to locate the
range of tests appropriate for a given individual. Yerkes’s method is conducive
to group testing, whereas the Binet–Simon test has to be given to one person at
a time. Soon Yerkes would see his method tried on a level he never dreamed
possible.
The Army Testing Program
When the United States entered World War I in 1917, Yerkes was president of
the APA. He called a special meeting of the association to determine how
psychologists could help in the war effort. It was decided that one way
psychologists could contribute was by devising means for selecting and
evaluating recruits into the armed forces. Yerkes and Terman, went to the
Vineland Training School to develop psychological tests that were then tried at
various army and navy bases. The results were encouraging, and Yerkes was
made an army major and given the job of organizing a testing program for the
entire army. Using Yerkes’s point-score method of scoring, the group created a
test that met these criteria; however, they found that 40% of the recruits could

49. not read well enough to take the test. The group solved the problem by creating
two forms of the test: the Army Alpha for literate individuals and the Army
Beta for illiterate individuals or for those who spoke and read a language other
than English. The war ended in 1918, and the testing program was terminated
in 1919, by which time more than 1.75 million individuals had been tested.
The Deterioration of National Intelligence
The use of the Army Alpha and Beta tests rekindled eugenic concerns about
the deterioration of the nation’s intelligence level. About half of the white
males tested in the army had native intelligence equal to that of a 13-year-old
or lower, and the situation was even worse for black soldiers. Goddard’s
response was that people with low mental ability should not be allowed to vote.
Along with Goddard, Terman and Yerkes were very concerned about the
deterioration of the nation’s intelligence, which they believed was caused by
immigration and the fact that “intellectually inferior” individuals were
reproducing faster than normal or above-normal individuals. As was common
at the time, Yerkes (1923) believed that many of the nation’s ills were being
caused by people of low intelligence and that immigration policies. Once again,
proposals arose for restricting marriage and for widespread sterilization of
individuals with mental deficiencies. At the time, however, a growing number
of prominent individuals were wondering whether so-called intelligence tests
actually measure genetically determined intelligence.
They argued that test performance is determined more by education and
personal experience than by inheritance. immigration. (p. 365) However, as we
have seen, this extremely nativistic position that Goddard, Terman, and Yerkes
represented did not go unchallenged. More and more, people realized that
performance on so-called intelligence tests could be at least partially explained
by such factors as early experience and education. Rather than simply
measuring native intelligence, the tests were apparently also measuring
personal achievement and the influence of life’s circumstances. Gould (1981)
notes that test items included questions about brand name food products,
baseball players, tennis, bowling, and phonographs. It followed that the more
privileged a person was in terms of enriching experiences and education, the
higher his or her scores would be on so-called intelligence tests. For example,

50. African American scholar Horace Mann Bond observed that blacks living in
the north typically scored higher on intelligence tests than those living in the
south. The book The Bell Curve:
Intelligence and ClassStructure in American Life (1994), by Richard J.
Herrnstein and Charles Murray, reflects many of the same beliefs about
intelligence accepted by Galton, Cattell, Spearman, Burt, Goddard, Terman,
and Yerkes. Herrnstein and Murray organize their book around six conclusions,
or points, about intelligence that are “beyond dispute.” By “beyond dispute,”
they mean the following :That if you gathered the top experts on testing and
cognitive ability, drawn from all points of view, to argue over these points,
away from television cameras and reporters, it would quickly become apparent
that a consensus already exists on all of the points, in some cases amounting to
near unanimity. (p.23). Here are the six points:
1. There is such a thing as a general factor of cognitive ability on which
human beings differ.
2. All standardized tests of academic aptitude or achievement measure this
general factor to some degree, but IQ tests expressly designed for that
purpose measure it most accurately.
3. IQ scores match, to a first degree, whatever it is that people mean when
they use the word intelligent or smart in ordinary language.
4. IQ scores are stable, although not perfectly so, over much of a person’s
life.
5. Properly administered IQ tests are not demonstrably biased against
social, economic, ethnic, or racial groups.
6. Cognitive ability is substantially heritable, apparently no less than 40
percent and no more than 80 percent.

51. Modern Testing and Psychometrics
Currently there is little agreement even on an adequate definition of
intelligence. When 24 prominent researchers in the field of intelligence were
asked to define intelligence, they provided 24 different definitions (Sternberg &
Detterman, 1986). Central to the problem is the issue we introduced with
Spearman and Binet: Is intelligence one generalized factor or a collection of
many different attributes?
U.S. psychologists revisited the idea that intelligence was best understood as
one factor
(Spearman’s g). Thurstone, 1938 suggests seven intelligence factors Robert
Sternberg’s (1986) three factor model has been widely embraced in recent
years, essentially accepting the traditional factor, but including considerations
for experience and context. Still, there is no universally agreed upon answer to
the question.
In addition to the previouslynoted contributions of Chronbach and Thurstone,
several other important American psychologists have distinguished themselves
in the area of statistics and psychometrics. Quinn McNemar (1900–1986;
APA president in 1964), Anne Anastasi (1908–2001; APA president in 1972),
Paul Meehl (1920–2003; APA president in 1962) made important
contributions to psychometrics. Quinn McNemar was responsible for many of
the various psychometric advances made to the Stanford–Binet, and published
the classic Psychological Statistics in 1949. Anastasi (1980) described her
career as being focused on how matters such as experience and environment
impacted development, and is best known for her extensive work on making
psychological tests valid measures. Among Meehl’s concerns was the
recognition that psychology relies on constructs such as intelligence that often
differ significantly from the entities studied by the natural sciences

52. David Wechsler
(1896–1981)
Just before WW II, David Wechsler developed a new intelligence test to better
understand his adult clients at Bellevue Hospital, the same facility where Leta
Hollingworth had once worked. Wechsler was born an East European Jew, one
of the groups most singled out by Goddard as unfit for immigration (Wechsler
came to the United States at age 6). During WW I, Wechsler served as a
volunteer scorer of the IQ tests being administered to U.S. soldiers.
In 1919, he went to the University of London and studied with both Pearson
and Spearman. Wechsler resolved some of the psychometric issues that had
been identified in the original Stanford–Binet and the Army Alpha and Beta by
no longer producing a score linked to age. Instead, the average score on his test
was set at 100, and higher and lower performances were evaluated against
deviations from that standard. Wechsler revised his test during and after WWII,
eventually producing both the WAIS (Wechsler Adult Intelligence Scale) and
WISC (Wechsler Intelligence Scale for Children).
In turn, the Stanford–Binet was revised to match Wechsler’s scoring. Although
numerous other scales have been developed, the WAIS and WISC along with
the Stanford–Binet remain the most widely used. After reviewing which of the
many notions concerning intelligence have scientific support and which do not,
Neisser et al. (1996) concluded the following: In a field where so many issues
are unresolved and so many questions unanswered, the confident tone that has
characterized most of the debate on these topics is clearly out of place. The
study of intelligence does not need politicized assertions and recriminations; it
needs self-restraint, reflection, and a great deal more research. The questions
that remain are socially as well as scientifically important. There is no reason
to think them unanswerable, but finding the answers will require a shared and
sustained effort as well as the commitment of substantial scientific resources.

53. .