Running head: SEX, MONEY, LOVE, STUFF 1 Sex, Money, Love, and Stuff; a Review of the Neurological and Neurochemical Correlates of Consumption and Pleasure John K. Carvalho Macalester College
Running head: SEX, MONEY, LOVE, STUFF 2 Abstract The current trend in neuromarketing is to apply neuroimaging techniques andneuroendocrinological ideas to help explicate relatively new phenomena discovered in the areasof consumption and purchasing behavior. Given neuromarketing’s status as a rapidly emergingfield, much of the research is fairly scattered and sporadic. Therefore, we aim to collate a varietyof the current research into a single report. Recognizing the multiple tracks that the researchtravels, we first divide our relevant behaviors and topic areas into subcategories like impulse andvalue, discussing neurological areas that have been indicated in each. In the second section, wediscuss the beginnings of research done into hormonal influences on purchasing andconsumption behavior. Finally, we make several suggestions for further areas of research.
Running head: SEX, MONEY, LOVE, STUFF 3 Consumption on some level can seem a little strange. Take one example.Save the lastthree hundred years or so (a mere blink in evolutionary time), human beingshave managed toeliminate their own waste fairly naturally; perhaps they used a hole in the ground or a woodenshack housed on the periphery of one’s property.Now, consider the Toto MS990CGR-12Neoresttoilet. According to its product description, it “has an automatic lid opener, automaticflush and automatic air purifier. It also features a heated seat with a remote control” (Lindner,2008). It retails for $5980, or approximately the average per-capita income of Botswana (UN,2009). It requires the utmost care to maintain, it is nearly impossible to effectively service at USdealers, unless one is lucky enough to reside in a major metro area. However, to those whoactually purchase one or several to outfit their living quarters, such considerations are likelymoot. Certainly, this consumption is wasteful and “conspicuous, term left to psychology by thesociologist ThorsteinVeblein, loosely defined as “attaining and exhibiting costly items to impressupon others that one possesses wealth or status (Sundie et. al, 2011). Now, not all consumptionis this extreme. However, two aspects of this type of consumption are especially important andgeneralizable and can thus serve as points of entry for a much broader discussion. First,universality across culture. These displays have been recognized in cultures as varied asPolynesian Islanders, Melanesian foraging communities in Australia, and Japan (Bird & Smith,2005; Godoy et. al, 2007). Additionally, we can place this type of consumption, as we can placemost consumption, into an evolutionarily influenced paradigm that derives naturally from aperspective of reproductive fitness and life history. And while conspicuous consumption isperhaps more overt sexual signaling, nearly all consumption can be considered as a studied
Running head: SEX, MONEY, LOVE, STUFF 4strategy of demonstrating one’s evolutionary fitness to other potential mates and allies.(Sundieet. al, 2011; Miller, 2009). However, a broad study of “sex, money, love, and stuff” from merely anevolutionarystandpoint would be incomplete. Focusing exclusively on these general, abstract considerationswould ignore significant progress that has been made on two fronts: both mapping andunderstanding the brain areas that are indicated in a variety of consuming behaviors, andfurthermore understanding the hormonal and neurochemical indicators of a variety of thesebehaviors. This is where the present review focuses. We will first divide our behaviors of interest into several subtopics, like value, pleasure,and impulse. We will then look at the relevant areas of brain activation for each subtopic.Next,we will review research that explores the link between hormones and neurotransmitters and avariety of consumption behavior. At times, sex will enter into the discussion; as it should,considering the links between consumption and sexual signaling. At times, evolutionarypsychology will unavoidably enter back into the discussion. However, our primary foci will be,in order, the two that we have discussed above. First, we’ll take a quick look at an emergingfield.What is Neuromarketing? The subfield that involves utilizing visual imaging techniques to understand and predictconsumption and purchasing behavior is loosely known as neuromarketing, a term thatsometimes carries over into areas of neuroeconomics and decision neuroscience; the long-termaim is often the optimization and streamlining of business and marketing objectives (Garcia&Saad, 2008; Ariely&Berns, 2010). There is some disagreement that exists about whether or nota single area in the brain is directly responsible for this list of behaviors, but most research does
Running head: SEX, MONEY, LOVE, STUFF 5in fact seem to suggest that they are not directed by one area but instead are a conglomeration ofa wide variety of cognitive functions in a wide variety of areas. That being said, there are certainareas of primary prominence and importance to these processes: the orbitofrontal cortex,striatum, and insula all are areas of focus- other miscellaneous areas have been differentiallyindicated as well (e.g., Padoa-Schioppa& Assad, 2006; Ariely&Berns, 2010). Because the field is still relatively new (a November 13th, 2011PsycINFO search for theterm showed a mere 24 peer-reviewed journal articles), a brief introduction to the topic isprovided simply to help provide a sort of explanatory framework under which much of thefollowing research could be placed.Perceptions of Value A large part of consumption and pleasure revolves around ideas of value. Valuemotivates purchasing behavior, and it is logical that we derive pleasure from that which offers usvalue. Logically, then, we would assign the most value to those items or options from which wederived the most pleasure, or the “strength of the current subjective experience (e.g., Kahneman,Wakker, &Sarin, 1997). Understanding how closely related the two concepts are, I’ll use themboth throughout this section. In the last decade, a variety of studies have helped lay the explanatory framework for thenewer research I examine here. This earlier research has suggested not only that people givetremendous weight to what they perceive an item’s “value” to be, but that their perception of anitem’s value and efficacy is based on cues that are not always particularly obvious (Rao et. al,1989), and frighteningly easy to manipulate (e.g., Shiv, Carmon, &Ariely, 2005).Furthermore,this manipulation can be done implicitly and outside subjects’ conscious awareness. More recentresearch, then, has used neuroimaging to begin to understand brain areas that are differentially
Running head: SEX, MONEY, LOVE, STUFF 6activated in these situations. As a result of this research, three major areas that have thus farbeen indicated in the perception and understanding of value are the orbitofrontal cortex, thestriatum, and the insula.The Orbitofrontal Cortex The orbitofrontal cortex is a prefrontal cortex within the frontal area of the brain and ismost directly involved in cognitive processing and decision making- in humans, it consists ofBroadmann areas 10, 11, and 47 (Kringelbach, 2005). Anatomically, it is the area of theprefrontal cortex that “receives projections from the magnocellular, medial nucleus of themediodorsal thalamus” (Fuster, 1997). As noted, the orbitofrontal cortex has been indicated in both primates and humans asbeing important whenever consumers perceive and evaluate value, be it economic value orotherwise (e.g., Padoa-Schioppa& Assad, 2006; Kringelbach, 2005).The OFC has been alsoimplicated in a variety of other contexts, from responses to music (Kringelbach et. al, 2003) toreminders of money (O’Doherty et. al, 2001). Recently, Plassmann and colleagues provided additional evidence of the importance ofthe OFC in value propositions, even when subjects were being misled about value.In theirexperiment, subjects were told that they were participating in a study wherein they would beasked to rate the tastes of various wines, after taking small sips and being instructed to hold theliquid in their mouths for a period of time. Wines were presented with simultaneous price cues.However, though subjects were told they were sampling five wines, they were in fact samplingonly three wines, two of which were each administered once in concert with a high price, andonce in concert with a low price. For clarity, the six stimuli were $5 wine (wine 1), $10 wine(wine 2), $35 wine (wine 3, a distractor), $45 wine (wine 1), $90 wine (wine 2), and a neutral
Running head: SEX, MONEY, LOVE, STUFF 7solution. What was interesting (and perhaps not particularly surprising) was that reports ofexperienced pleasantness were strongly correlated with price cues. That is, when told that the $5wine was in fact a $90 dollar wine, subjects enjoyed it more. Interestingly, though, this was notjust a question of perception. When tasting the “expensive” $5 wine, subjects also showedincreased blood-oxygen-level-dependent activity in the OFC. Subjects appeared to not merely befooled on a level of superficial perception, but on a very real neurological level as well(Plassmann et. al, 2008). Reinforcing the evolutionary nature of many of these areas and phenomena wementioned, indications of similar circuitry with similar purposes have been found in primates.For example, when monkeys were deciding between and ascertaining the relative quality ofbeverage options (either water or a sweetened Kool-Aid), OFC neurons were shown to aid in theencoding of each choice’s respective value and in then promoting a final decision of thebeveragethat appeared to offer the highest value (Padoa-Schioppa& Assad, 2006). Finally, recent research has helped shed light on specialization within the cortex, asdifferent areas within the OFC seem to be indicated for slightly different aspects of behavior. Byexposing a subject pool of college males to money and visually erotic pictures (a task whichundoubtedly the subjects only agreed to do under extreme duress), recent fMRI research has bothfurther explained the nature of this hedonic pleasure center, and provided additional evidence tounderstand it from within an evolutionary framework. It appears that the OFC has “reward-specific representations”, areas within the cortex that are preferentially indicated depending onthe situation. The anterior lateral OFC, a structure that is phylogenetically more recent, appearsto process monetary gains, whereas it appears that the posterior lateral OFC, evolutionarily anolder structure, was the most key in processing and understanding basic erotic stimuli. This
Running head: SEX, MONEY, LOVE, STUFF 8seems inherently logical from an evolutionary standpoint- certainly humans needed the ability toassess and respond to stimuli closely associated with reproduction before they required theability to handle money or developed its association as a secondary reinforcement (Sescousse,Redoute, &Dreher, 2010).The Striatum The striatum is a subcortical area of the forebrain that can be divided into three areas.They include the ventral area, which is associated with limbic functioning, the central area,which is indicated in associative functioning, and the dorsal area, which seems most indicated insensorimotor functioning. The most important output areas of the striatum target motor andcognitive action systems and premotor brainstem areas (Haber, et. al, 2000); the area isphylogenetically older, and found in some form in a variety of mammals and primates. In a direct contrast to the base nature of the value appraisals encoded in the OFC, thestriatum seems to be most activated during situations that involve slightly deeper, more complexchoice decisions and value encodings.For example, the striatum was strongly indicated whenbeing asked to differentiate between hypothetical choices and real choices, which have beenshown to differentially activate common value areas(Kang et. al, 2011). Elucidating further the ability of the striatum to appraise and understand much lesstangible, more abstract ideas of value and reward, recent work has also been done to highlightthe striatum’s role in combining various abstract reward “currencies” (the promise but notpossession of money, social approval, et cetera) into a common currency of sorts,and then helpmake a judgment of value and encourage a decision. In this case, subjects (who weresimultaneously being scanned in an fMRI machine) were allowed to make the choice whether todonate hypothetical money to a variety of charities or whether to keep the money. However, the
Running head: SEX, MONEY, LOVE, STUFF 9key manipulation was that during some of the forced-choice donation decisions, subjects weremade to believe that their choice was being watched and recorded by visible (and important)observers in an adjacent room. The behavioral evidence was unsurprising- the mere presence ofobservers increased donation rates, as subjects clearly were invested in being seen by others asthe type of people who do things like donate to charity whenever given the opportunity.However, neuroimaging results showed that activation in the striatum immediately before thedecision was significantly affected by the presence of observers. Proportionality was observed aswell: particularly high striatal activations were observed when a high social reward wasexpected, and also when there was the possibility for the acquiring of money without anaccompanying social cost (Izuma, Saito, &Sadato, 2009). Even more recent research has brought the importance of the striatum to an even higherlevel. Because activation in this area was indicated for the first time in value considerations whenno choice task was actually required, striatal activity was used to essentially predict futurepurchasing behavior. Subjects passively viewed twenty consumer goods, ranging fromDreamgirls DVDs to art prints by Dali, while being instructed to simply think about how muchthey would theoretically pay for the item in question. Later, removed from the scanner, subjectswere presented with pairs of items from the list they had just viewed and were asked a simplequestion: which of these would you like to purchase? Significantly, the subjects’ preferentialanswer to that question could be strongly correlated to the level of BOLD activation that theyhad previously shown in the striatum, even though they had previously been engaged in merepassive viewing. That is to say, had experimenters wanted to pick which item the subject wouldchoose to buy, they needed only to look and see for which of the two items the subject hadshown the highest BOLD activation in the striatum.
Running head: SEX, MONEY, LOVE, STUFF 10Medial Frontal Cortex It appears that the medial frontal cortex is also indicated in perceptions of pleasure andproduct attractiveness, and more abstract conceptions of “willingness to purchase”, and a varietyof other ancillary purchase-related behaviors. In general, the MFC is implicated in anticipation,and potentially additionally implicated in basic value assessments (similar to the OFC), and hasbeen indicated in a manner similar to the striatum when it comes to predicting purchase behavior(e.g., Knutson et. al, 2007). However, some of the most promising, specific new research seems to indicate the MFCas being key in perception of and understanding of brand loyalty. Lin, Tuan, and Chiu consideredMFC activation using an interesting protocol (near-infrared ray imaging), but compared it as itdiffered between those who are loyal to a certain brand, and those who are not. So, in the luxuryspace it appears that those who are particularly brand loyal are more sensitive than switchers inbeing able to tell between both luxury and generic brands and being able to differentiate betweenattractive and unattractive products, and that increases in MFC activity is correlated stronglywith this entire process (Lin, Tuan, & Chiu, 2010). This seems logical- certainly one who has astrong predilection for Gucci handbags is probably very astute at both quickly spotting fakeGucci bags, and quite fast at visual perception and categorization of the bags whenever andwherever they might encounter them.Perceptions of Pleasure Although a thorough discussion of how we neurologically derive and understandconcepts of value is key to any discussion of consumption behavior, there are other keypsychological, neurological, and emotional mediators of these types of decisions. I would arguethat considerations of pleasure and attachment are an important consideration when discussing
Running head: SEX, MONEY, LOVE, STUFF 11these behaviors. Although we have mentioned that value and pleasure are related and used themsomewhat interchangeably, some research considers not our encodings of value or propensity tomake forced-choice decisions, but hones in on more visceral feelings of joy, connection, orpleasure.The Insula It is a fairly familiar experience to encounter those who claim addiction to their varioustechnological items, be them Blackberries or iPhones. What is perhaps more surprising is thatrecent (if controversial) research has suggested that “addiction” might be perhaps the wrongword to use to describe the feeling to which the consumers refer. Branding and marketingconsultant Martin Lindstrom, with the aid of a neuromarketing firm, recently invited such agroup of self-professed iPhone “addicts” into a room, where they underwent fMRI scanningwhile being played audio and video of an iPhone ringing. The neural location of addiction is complex and poorly understood, but is typicallythought to involve a variety of brain areas, including strong involvement of the striatum, reducedvolume (in the case of drugs) in much of the dopaminergic circuitry (specifically theperiaqueductal grey matter), and much of the prefrontal cortex (e.g. Barros-Loscertales et. al,2011). However, in this case, Lindstrom found something very different-comparatively verylittle activation in any of these areas, and a tremendous amount of activity in the insular cortex,an area strongly associated with love and compassion. So, it certainly seems that in aneurological sense, people are not addicted to their iPhones, but rather are very much in lovewith them (Lindstrom, 2009).Impulse Control: Regulating and Resisting Hedonic Temptation
Running head: SEX, MONEY, LOVE, STUFF 12 There is a vast psychological literature on impulse buying, its correlation to the depletionof stores of willpower, and the like (e.g., Vohs& Faber, 2007), but only relatively recently hasthe research moved to integrate neuroimaging and the neurochemical approach. In this case,cutting-edge research has been able to highlight the ways that we struggle to resist temptation.Anterior Cingulate Cortex Perhaps the most notable and relevant new line of research seeks to tie together impulsecontrol in the realm of money and purchasing to visceral and neurological, physical inhibitorydrives that can be quantified, imaged, and measured. This phenomenon is called “inhibitoryspillover”, and the anterior cingular cortex seems to be the key area of interest. Tuk and colleagues provoked feelings of urination urgency in subjects, and self-reportedhigher levels of bladder pressure were found to actually lead to subjects’ improved abilities toresist the making of impulsive financial choices (in this case the choice was between a smallreward the next day and a much larger reward several days later). These results suggestextraordinarily strong connections between visceral drives and neurological activity (Tuk,Trampe, &Warlop, 2011). That is to say, the inhibition required in “holding it in” carries over tothe inhibition required to resist financial temptation. Although the neural correlates of urination are many, and the pathways are locatedthroughout the brain, the anterior cingulate cortex appears to be equally key in both inhibitingurination and cognitive inhibition (Berkman, Burklund, & Lieberman, 2009; Griffiths &Tadic,2007; see also Fowler, Griffiths, & de Groat, 2008). To add further context, the ACC was alsorecently shown to be activated less frequently and with less strength in those with compulsivebuying psychological disorders when they were given the opportunity to make purchasedecisions (Raab, Elger, Neuner, & Weber, 2011), suggesting that those who were, in effect,
Running head: SEX, MONEY, LOVE, STUFF 13giving into temptation were activating the ACC at a lower level as they eventually succumbed totheir desires.Hormonal Activation In the area of neuromarketing, the most important hormonal/neurochemical activationsare of testosterone and estrogen.Given the evolution-oriented discussion surroundingconsumption; the link between consumption and sex, evolutionarily, seems to be strong.Testosterone Testosterone has been implicated in a variety of behaviors tangentially related to ourtopic. One can synthesize a variety of applicable literature to suggest that higher levels oftestosterone seem to be indicated in risk-taking behavior of a variety of sorts, ranging frommaking risky financial decisions to pathological gambling (e.g., Senstrom et. al, 2011; Olsen &Cox, 2001). One can furthermore extrapolate that risk taking financial decisions certainly wouldbe correlated with risky purchasing behavior and impulsive consumption strategies. The interaction between testosterone and consumption (especially conspicuousconsumption) has only begun to be studied recently. There is, of course, the basic argument thatany consumption at all serves as a mechanism that allows humans to signal their social status andmating potential to prospective allies and mates (e.g., Miller, 2009). Testosterone, being a keysex hormone, would then logically be involved. Conspicuous consumption, by this rationale, is asort of wasteful signaling. Think of a male peacock’s tailfeather plumes; they’re large, unwieldy-they render peacocks easily visible to predators, slow down their travel. So, amale peacock withlarge feathers is essentially communicating “look at me; I have body parts that should make me atarget to predators and lessen my survival chances, yet I’m still alive; as such, I must begenetically fit to mate.” Given testosterone’s status as a sex hormone, it is thus unsurprising to
Running head: SEX, MONEY, LOVE, STUFF 14find an interaction between testosterone and aggressive, conspicuous consumption. Men weremade to drive both a dilapidated old station wagon and a high-end Porsche convertible in publicspaces, and men’s testosterone levels (as measured by saliva immunoassay) actually increasedafter driving the Porsche in public and decreased after driving the station wagon (Saad&Vongas,2009). For more context, recent research has used the biopsychosocial approach and attemptingto trace the key behavioral correlates of testosterone throughout the lifespan (e.g., White,Thornhill, &Hampson, 2007). Prenatal influences of testosterone are actually fairly wellestablished as well, as recent research has found that testosterone levels and their accompanyingeffects seem to be set before birth. Stenstrom and others (2011) looked at second to fourth digit length ratio (2D:4D), a wellknown indicator of prenatal testosterone exposure, and tested subjects to ascertain their level ofrisk-taking behavior across five different behavioral domains: financial, health, social, ethical,and recreational. The researchers found that those who had digit length ratios that wereindicative of high-level prenatal exposure to testosterone were in fact more likely to exhibit risk-taking behaviors, though chiefly across the social and recreational domains, which theresearchers theorize is likely because evolutionarily, these were the two domains that were likelythe most effortless for individuals to use to most quickly and efficiently demonstrate theirgeneral social and mating desirability. In sum, much of the testosterone-related research seems to highlight two main ideas.First, when given the opportunity to interact with products of a certain value and thus associatewith those products, men saw increases in their sex hormones. Second, testosterone levels seemto be positively correlated with a high level of risk taking behavior, across several domains-
Running head: SEX, MONEY, LOVE, STUFF 15research is needed to explore how those behaviors translate into the purchasing sphere, andperhaps how testosterone levels change how consumers interact with marketing messages.Advertising strategies for a variety of companies in the CPG space thrive on driving purchasingthrough making customers “feel more manly”- what neurological factors are at play here?Estrogen Similar to the importance of testosterone in males, females seem to have a fair amount ofrelevant behaviors mediated by the relevant sex hormone, estrogen. From an endocrinologicalstandpoint, human females are especially unique. Importantly, human females are one of therarer species that do not clearly advertise their peak points of fertility throughout the ovulatorycycle in a way that is visible or obvious to male conspecifics. So, while much of the testosterone-consumption link appears to be sexually motivated, we might think of females’ task in thissituation as being even more urgent. Lacking any natural outward signs of peak fertility, it thencomes to patterns of consumption and choices of accouterments to advertise this most valuableinformation. The body of research that addresses these types of changes across the fertility cycle isstill emerging. Nonetheless, recent research has begun to lay the explanatory groundwork formore advanced inquiries that are sure to follow. A sample of thirty women that were currentlypartnered in relationships and had not taken any contraceptives for a period of ninety days werephotographed in their typical dress, with their hands at their sides. Over the course of severalweeks, women were photographed at both their high-fertility point in their ovulatory cycle, andat a time of lower fertility in their cycle. Impartial judges were asked to look at the pictures andattempt to discern whether the women were in their most fertile phases or whether they were not.At levels that were significantly above chance, judges selected photos of women in their fertile
Running head: SEX, MONEY, LOVE, STUFF 16phase and deemed those photographs as representative of the subject “trying to look moreattractive.” As such, it appears that women naturally and subconsciously engage in grooming andornamentation strategies in order to help indicate their most fertile phase to potential suitors(Haselton et. al, 2006). Recent research continued that line of reasoning even further. It appears that at theirhormonal peak, women unconsciously choose products that enhance their appearance (i.e.choosing asexy, revealing skirt over a conservative pantsuit). Hormonally regulated, it appearsthat this effect may emanate from a desire to outdo attractive women that are potential rivals. Assuch, it followed that when the researchers reduced the salience of these potential rival women,the ovulatory effect on these product choices reduced as well (Durante et. al, 2010).Conclusion and Directions for Future Research As noted, neuromarketing and the application of neuroimaging techniques toconsumption and purchasing behavior is a relatively new field. The general trend that has beenexplicated here is that although consumption and purchasing behavior has been studied fairlyextensively in the last decade or so (and has led to findings that are on their own quiteinteresting), it is only recently that neuroimaging protocols have been applied, andneurochemical considerations have been made. Connections are still being drawn between priorresearch and strategies to integrate new techniques. There are ethical considerations as well,since much of this research is being integrated into business decisions (e.g., Ariely& Burns,2005). As the field grows, though, the applications will lead to research and application in avariety of areas. Consider for a moment the work done on placebo effects, perceptions of value, andquality (see Baba, Ariely, & Shiv, 2005; Plassman et. al, 2008). As we become more and more
Running head: SEX, MONEY, LOVE, STUFF 17familiar with the ways that perceptions of price and quality are so thoroughly integrated into thebrain on a deep, neurochemical level, the applications in marketing could be interesting indeed,and the potential points for problems could become clear. For example, are discount drugproblems a particularly good idea, if it appears that perceptions of a product’s value andtherefore its efficacy can be so easily manipulated? Additionally, the discussion of hormones was brief, precisely because the researchpresently is still fairly thin. Especially with estrogen, more research needs to be developed tofully understand the significance of changes in purchasing behavior throughout the ovulatorycycle. An interesting angle that merits exploration here would be how cyclical changes mediatefemale purchasing behavior when the items they are purchasing are not for them. It is acceptedwisdom in marketing circles that women are responsible for approximately eighty percent ofhousehold purchases. Therefore, novel research should aim to flesh out the changes inpurchasing and behavioral presentation women undergo during these cycles and see if thechanges are reflected in purchases for her spouse or her family members. During the peak of herreproductive cycle, could she be concerned, for example, with clothing her male partner in a lessattractive way in order to continue to stave off potential female competitors? The possibleanswers to these and other questions could have immediately applicable effects in marketingcontexts, especially given the segmentation strategies used by marketers. In a more neurological sphere, the challenge is twofold. Number one, specificity- theOFC, we have seen, is key in representing value encodings. However, considering Plassmannand others (2008), an interesting manipulation would be to repeat the study of wine preferencebut with something like so-called “expert reviews” being manipulated, rather than price cues, tosee if the effect is repeated. Such an experiment would help explain further the exact nature of
Running head: SEX, MONEY, LOVE, STUFF 18the “value” that is encoded in the OFC. The second challenge will be integrating the hormonalwork (which, as stated, remains thin) with the neuroimaging work to establish a more holisticlook at how these processes work in concert.
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