Psychothalamus

On Evolutionary Explanations of Restrictive Eating Disorders, and the Value of Radical Ideas

2012-01-06T03:45:00.000-08:00

Evolutionary theory posits that every psychological, behavioural and physical trait expressed by an organism was selected for by aiding the organism in its survival and/or reproduction, and therefore had a functional purpose for existing at some point in evolutionary time. A trait could never exist if the environment was not conducive for its expression (i.e. hinders the organism in survival or reproduction).

By this logic, it might therefore be reasonably assumed (however inconceivably) that there could have been some adaptive function for the existence of anorexia and bulimia at some point in our evolutionary history. They are annoyances in our modern world because there could be a mismatch between its usefulness in the ancestral past and the environment today.

There are at least five major evolutionary explanations for restrictive eating disorders, each with its own flaws, as outlined by Dr Igor Kardum and colleagues from the University of Rijeka in a 2008 paper reviewing evolutionary accounts of anorexia and bulimia, namely (1) the reproduction suppression hypothesis (Wasser & Barash, 1983), (2) the model of parental manipulation (Voland & Voland, 1989), (3) the sexual competition hypothesis (Abed, 1998), (4) the adapted to flee from famine hypothesis (Guisinger, 2003), and (5) the combined concepts of 'social attention holding power' and the 'need to belong' (Gatward, 2007).

The most palatable (and, thus, conventional and popular) idea tends to revolve around competition among females catalysed by the media (sexual competition hypothesis). It is the notion that in wealthier societies, to be able to resist food is seen as a mark of having high status, while in poorer societies, to be able to get food is conversely the indicator of high status; thus anorexia is more prevalent in modernised societies while relatively larger-sized females are exemplified as beautiful. This is propagated via media imagery.

I will not go into detail with all the ideas as it can get rather technical, but in particular I wanted to point out two radical ideas put forth that, while still works-in-progress, were really interesting and reflective of creative, convention-defying attempts to think of new ways to consider this issue.

In particular, I thought Voland and Voland's (1989) model of parental manipulation interestingly attempts to account for why eating disorders tended to happen more with wealthier, higher class individuals. This model draws on kin selection theory and asserts that anorexia may be adaptive (useful) insofar as it increases an anorexic's helping behaviour to her own kin's survival and reproduction while suppressing her own reproductive success (because anorexia leads to a decline in fertility). Non-evolutionary research in the 70s showed that members of anorexic families possessed mutually overprotective attitudes, and anorexic individuals tended to worry constantly about the well-being of their families. In the ancestral past when families were larger, anorexic female helpers could suppress their own reproduction and therefore divert their own resources towards helping collateral kin, leading to greater inclusive fitness (genes belonging to family members). This sets the precedent for some interesting speculations. The model of parental manipulation suggests that anorexia is actually somehow exacerbated by parental influence. Many studies report significant correlations between dominant and overprotective mothers and the probability of anorexic reactions of their daughters. Anorexia reduces a female's fertility and hinders her from bearing additional offspring. Additionally, when a daughter is overprotected and dominated by her mother, her ability to find a mate is also reduced. In wealthy families, males are the more valuable sex as they have the resources to attain more mates. By inducing anorexia (thereby restricting the reproduction of daughters and also reducing their food intake), especially for families in higher societal strata and class, parents can then concentrate investment potential towards sons, who in wealthier families have higher reproductive value.

The next radical idea is Gatward's (2007) combined concepts of 'social attention holding power' and 'the need to belong'. 'Social attention holding power' is defined as an individual's ability to hold attention and gain investment from other members of the group, and this concept is closely related to the degree to which a person feels in control. Naturally, higher status individuals hold more social attention in their group and feel more in control. The need for belonging to a group is a fundamental human need, as ancestors who did not belong to any group were unlikely to survive for long in the harsher environments of the past. Because survival depended on belonging to a group, people had to compete for resources and this competition could lead to exclusion, if one wasn't careful. Anorexia might therefore have been adaptive in the past to prevent competition for food and resources, as well as compete in a more nuanced manner for status (a reference to the more conventional sexual competition hypothesis outlined above), thereby promoting group harmony and reducing the likelihood that one might get expelled. I would personally go on to speculate that in our modern society (essentially functioning and subconsciously perceived as a really large group), nobody feels like the highest status female who doesn't need to conform to restrictive eating disorder, because there is an implicit assumption that the highest status female is the one they see artificially created by the media. So everyone else who feels subordinate will increase her tendency to engage in restrictive eating disorder, an adaptation brought on by the need to maintain the large group's social harmony.

These are certainly radical theories that need to withstand more empirical testing, but it is exciting to read them because they represent interesting attempts to get away from more conventional and acceptable ideas that do not necessarily get us very far, as evidenced by the fact that many extant theories on the causes of eating disorders still have ambiguities and gaps. Of course, there has to be a deal of initial plausibility, lacking which we would just think the idea is quack. But science is ultimately pushed by great thinkers with ground-breaking insights.

On a concluding note, the authors of the review paper highlight one consistent element found among all proposed evolutionary theories of restrictive eating disorders - response to threat. All the major evolutionary explanations can be reasoned as a form of response to threat (to survival and/or reproduction) that leads people (especially females) to develop symptoms of eating disorders. This independently corroborates research linking eating disorders with feelings of insecurity and need for control.

Abed, R. (1998). The sexual competition hypothesis for eating disorders British Journal of Medical Psychology, 71 (4), 525-547 DOI: 10.1111/j.2044-8341.1998.tb01007.x

Gatward N (2007). Anorexia nervosa: an evolutionary puzzle. European eating disorders review : the journal of the Eating Disorders Association, 15 (1), 1-12 PMID: 17676667

Guisinger S (2003). Adapted to flee famine: adding an evolutionary perspective on anorexia nervosa. Psychological review, 110 (4), 745-61 PMID: 14599241

Kardum, I., Gračanin, A., & Hudek-Knežević, J. (2008). Evolutionary explanations of eating disorders Psychological Topics, 17 (2), 247-263.

Voland, E., & Voland, R. (1989). Evolutionary biology and psychiatry: The case of anorexia nervosa Ethology and Sociobiology, 10, 223-240

Wasser, S., & Barash, D. (1983). Reproductive Suppression Among Female Mammals: Implications for Biomedicine and Sexual Selection Theory The Quarterly Review of Biology, 58 (4) DOI: 10.1086/413545

Sexual Strategies Underlie Religious Inclinations

2011-10-04T09:30:00.000-07:00

The positively correlated associations between religiosity (of a Christian-centric nature) and low levels of promiscuity and high levels of abstinence and marriage-centricity are generally quite clear enough. We often see that religion seeks to suppress sexual promiscuity through its doctrines that promote a monogamous sexual reproductive strategy characterized by low promiscuity, exclusive heterosexuality and high premiums on marriage and fertility.

Intuitively, we might guess that our sexual inclinations owe to how much exposure we have towards our adopted religion. Thus, we might, quite reasonably, suppose that someone who regularly attends Sunday school and comes from a religiously devoted family with staunch practices in the home would more likely be shaped into a long-term mating, marriage-inclined and sexually abstinent person, than someone who does not observe those traditions and customs. Indeed, it was found that treating premarital sex as sinful creates incentives to marry earlier, and condemning abortion and birth control as sin makes people have children.

However, when we look at the US, which is considered the most religious nation compared to its other western counterparts, what is fascinating is that it is remarkably evenly divided - approximately 42% of adults never attend religious services, 18% attend intermittently, and 40% attend services regularly (information from the 2006 US General Social Survey).

This suggests that, while a country may adopt non-secular values to predominantly guide its affairs and inform its citizens, not everyone may agree or be inclined to go along with those values. In the case of the US, this divide is exemplified by the emergence of the Religious Right and the Liberal Left.

As evolutionary psychologist Kenrick (2011) colloquially and aptly states it, "the prototypical member of the Liberal Left ... may wait until at least the end of college before marrying and beginning to have children and then may delay even a few years longer to go to graduate school, law school or medical school. Because the human ability to resist sexual urges has a hard time outlasting all that postponement, these folks do not like the Religious Right's attempts to impose rules against premarital sex [or] tools of family planning. ... [The Liberal Left pose a problem for the Religious Right] because a large number of sexually loose young people playing the field threatens to disrupt the strict system that religious folks have set up to enforce and reinforce family bonds."

Working on that insight, Weeden, Cohen and Kenrick (2008) proposed the reproductive religiosity model - instead of religiosity affecting our mating strategy (whether we can be promiscuous short term maters, or should be committed, abstinent long term maters), it is instead our mating strategy that makes us calculate the costs and benefits of adopting a religion, or remaining devoted to our current religion. If I am unable to bear the cost of abstinence from premarital sex and I do not want to marry early, my exit strategy is to drop my impeding religion.

By analyzing data from two large sources - 21,131 respondents in the 2006 US General Social Survey and 902 undergraduate students who were probed about their family plans, sexual attitudes, religious attendance, and moral feelings about issues ranging from lying to stealing - it was found that the strongest predictors of religiosity were factors related to sexual and family values. While there were other typical variables that predicted for religiosity, such as being female, older, or a non-drinker, and being high in conscientiousness and low in sensation-seeking, statistically controlling for sexual and family value items made the links between these other typical variables with religiosity disappear. In other words, everything we might have assumed to be associated with religiosity can be boiled down to sexual and family values. The study by Weeden, Cohen and Kenrick (2008) thus provide evidence that, on average, whether we are religious or not in the first place depends on how promiscuous we want to be.

If that causal link is true, could it be possible to manipulate people's mating strategy and thus alter their religiosity, in the psychology laboratory no less?

A study by Li, Cohen, Weeden and Kenrick (2010) sought to test that idea. A cleverly deceptive cover story and elaborate experimental design was used, but in brief, participants were ultimately made to look at either desirable members of their own sex or desirable opposite sex members (such a priming method has been found to be effective in conjuring either a mating motivation state - when we check out attractive opposite sex persons - or a mating threat state - when we are made to look at attractive same sex persons). Participants were also made to fill out a survey on the pretext of finding out their attitudes; embedded in the survey were questions pertaining to religiosity.

The results showed that when the men looked at attractive ladies and when the women looked at attractive guys, there was no discernable effect of mating motivation on religiosity. Interestingly, the laboratory setting was unable to capture any desire to give up religion when participants were made to feel more motivated to mate. However, what was more interesting was that, instead, participants who looked at attractive members of one's own sex expressed greater belief in religion. Being primed with mating insecurity leads people to become more religious.

We see support here for the classic antagonism played out between the Religious Right and Liberal Left. Once again, Kenrick (2011) states it best, so he will be quoted here: "When you become aware that there are a lot of highly attractive mating competitors out there, it reduces the perceived benefits of playing a fast and loose mating strategy ... For women, a lot of attractive competitors means less attention from the attractive men who might provide good genes, and fewer fellows vying to support your offspring. For men, on the other hand, an abundance of especially handsome and available guys means that if you are playing the field, you may be playing with yourself for most of the game. Under circumstances of limited opportunities, any normal person - who does not look like a fashion model - could benefit from the religion-based supports for monogamy."

This is not to say that religious practices do not reduce sexual promiscuity - all other things equal between two people who are subjected to different levels of religious piety, we would expect the one who has been told that things like premarital sex are sinful would be less inclined to do the deed. However, these studies highlight another crucial direction in the causation, that sometimes people may choose how religious they want to be based on the perceived cost of carrying out sexual "transgressions" under the religion they are affiliated to. And at the heart of the differing values the Religious Right and the Liberal Left promote, each camp is sustainable because they encourage and reinforce different mating patterns; there is antagonism only because a clash of these value systems is highly disruptive to each side's foundations for their own reproductive status quo.

Weeden, J., Cohen, A., & Kenrick, D. (2008). Religious attendance as reproductive support Evolution and Human Behavior, 29 (5), 327-334 DOI: 10.1016/j.evolhumbehav.2008.03.004

Li YJ, Cohen AB, Weeden J, & Kenrick DT (2010). Mating Competitors Increase Religious Beliefs. Journal of experimental social psychology, 46 (2), 428-431 PMID: 20368752

We're back!

2011-08-01T11:14:00.000-07:00

We're back! After a long hiatus as a resultant mish-mash of graduation, traveling and everything else in between, Psychothalamus is ready to churn out more interesting reads once again.

Before that, we thought it'd be nice to share with our readers what we've been up to and where we're headed.

Jose wasted no time hitting the road the moment his final finals ended. Within hours of his last examination paper, he was jetting off on his graduation trip from Singapore to Ho Chi Minh City. Over the course of some very crazy 45 days, Jose traveled from Ho Chi Minh City to Phnom Penh, Siem Reap, Bangkok, Vientiane, Vang Vieng, Nong Khai, Delhi, Agra, Jaipur, Kathmandu and Pokhara. The traveling didn't end there though; upon settling down back home, he was off again to Washington DC to attend the 2010 APS Conference, where he presented a poster on the findings of his Honours Thesis. Officially graduated, Jose will be spending the next year working on a few projects at the Behavioural Sciences Institute of Singapore Management University before applying for graduate studies.

To celebrate getting admitted into graduate school, QH travelled over 6000km by rail and road on his epic tour of China, spanning 28 days, visiting a grand total of ten UNESCO sites. He suffered a severe bout of Montezuma's revenge on the trip and came back with a 100RMB counterfeit currency in his wallet. He is now trying to get himself fired up for the long road ahead as he prepares to pursue a PhD in cognitive neuroscience in the fall of 2011.

Shawn did not have all that much money to travel, so he satisfied his travel cravings with a three-day trip to Japan, of which two days were spent in Akihabara, the otaku mecca of anime and videos. The rest of his time was filled up by compulsory physical training to maintain his fitness levels for the Singapore Army, and preparation for his PhD at the National University of Singapore Graduate School for Integrative Sciences and Engineering, where he will be combining his love for Neuroscience and Genetics.

A Professional Distaste for Administration?

2011-07-08T05:05:00.000-07:00

Ever had to deal with difficult administrative personnel pressing you to adhere to some (@?$&#!!) company policy? Regardless of your own personal experiences, the euphemisms abound for administration (the powers that be, the higher ups, paper tigers, tai chi masters, etc) suggest that the administrative department is difficult, bureaucratic, meddling and restrictive. As a young employee joining a company, one of the first few things an attached mentor often shares in a "between you and me" moment is his or her gripe with administrative policy.

Administrators do have a crucial role to play in organisations. They set the boundaries and parameters within which organisation members are allowed to play. Administrators are often (either perceived as or truly) detached from the idealisms of the organisation, as their primary function is to regulate the workflow and processes of the organisation, in the hopes of ensuring that certain outcomes (often mundane ones) are achieved, such as neater procedures, safety, transparent accounts, etc. It therefore often makes sense to employ administrators who might not share the same essential pursuits of the other members of the organisation, so that a more objective and strict execution of implementations, policies, rules and regulations can result. Enforcing the red tape, so to speak.

How do people respond to difficult, strict and/or assertive administrators, particularly when those administrators are attempting to necessitate certain policies? According to a 2009 study done by Hekman (University of Wisconsin-Milwaukee) and Steensma, Bigley and Hereford (University of Washington), our likelihood of responding positively to administrative pressure (such as to adopt new work behaviour) depends on the degree to which we identify either with our profession or our organisation.

Formalising administrative pressure as Administrative Social Influence (ASI), the authors found that professional employees were most receptive to ASI to adopt new work behaviour when they strongly identified with the organisation and weakly identified with the profession. Conversely, ASI was counterproductive when professional employees identified strongly with the profession while identifying themselves weakly with the organisation.

The authors showed this by looking at a sample of about 200 primary care professionals from a large, non-profit health maintenance organisation. ASI was carried out to get the health professionals to adopt a new internet-mediated email-based technology called secure messaging, designed to reduce patient demand for office visits which in turn lowers expenses. Compliance with ASI was thus the measured dependent variable - whether the health professionals responded promptly (within 24 hours) to secure messages from their patients. The health professionals' organisational and professional identification was measured, and their identification was correlated with their tendency to follow through on the call to use secure messaging. Additionally, their perception towards ASI pressure was measured as well.

The results of their study showed that the more health professionals thought of themselves as part of an organisational team (strong organisational identification), the more they were likely to comply with new work behaviours solicited via ASI, and the less likely they were to perceive ASI as pressuring. The authors cite evidence that administrators are generally seen as "organisational guardians" (Freidson, 2001) and as "prototypical organisational members" (Golden et al., 2000), and when organisational identification is high, "professional employees’ sense of self is tied closely to a group that includes administrators. As a result [...] organizational identification leads professional employees to believe that organizational administrators are like them and on their side." On the other hand, people who identify strongly with their profession care very much about their professional responsibilities and tend to be skeptical of the interests and agenda of administrators who appear to care more about efficiency and profitability rather than high quality service. So, when health professionals have a greater sense of oneness with the nature of their profession rather than the bigger organisation they work within (strong professional identification), they were less likely to comply with new work behaviours solicited via ASI, and were also more likely to perceive ASI as meddling and demanding.

The authors thus conclude that ASI is effective only in limited contexts (i.e., only when one type of identification was relatively high while the other was relatively low). While the authors prudently keep away from commenting on their personal feelings towards "the powers that be", their study implies that organisations should consider encouraging greater social identification of their employees with the organisation if they want to increase employee compliance with new implementations. Might prove less of a problem with professional administrators...

Hekman, D., Steensma, H., Bigley, G., & Hereford, J. (2009). Effects of organizational and professional identification on the relationship between administrators’ social influence and professional employees’ adoption of new work behavior. Journal of Applied Psychology, 94 (5), 1325-1335 DOI: 10.1037/a0015315
Golden, B., Dukerich, J., & Fabian, F. (2000). The Interpretation And Resolution Of Resource Allocation Issues In Professional Organizations: A Critical Examination Of The Professional-Manager Dichotomy* Journal of Management Studies, 37 (8), 1157-1188 DOI: 10.1111/1467-6486.00220

Freidson, E. (2001). Professionalism: The third logic. Chicago: University
of Chicago Press.

Sacred Values as Heuristics

2011-02-24T09:00:00.000-08:00

Can being faced with a decision involving morals be a good thing? Research has shown in the past that morally-laden decisions are perceived as difficult and unpleasant. Therefore, conventional wisdom suggests that people would react characteristically when faced with decision-making with moral considerations, such as avoiding being placed in a position to make moral decisions, or effortfully spending more time deliberating over difficult moral decisions.

However, perhaps there's more to it than meets the eye, and Hanselmann and Tanner from the University of Zurich think so. In a very concise study, Hanselmann and Tanner (2008) sought to show that the involvement of moral issues and values can, instead, actually facilitate our decision-making. By invoking what are known as sacred values (absolute and inviolable values), we may end up spending less time thinking about the dilemma simply because an option that has sacred value makes us think that it cannot be compromised.

Every dilemma or decision involves some extent of trade-off. The authors conceptualized three types of trade-offs for the study:

Taboo trade-off
a situation that pits a secular value (i.e. a value that does not hold moral worth) against a sacred value

Tragic trade-off
a situation that pits two sacred values against each other

Routine trade-off
a situation that pits two secular values against each other

One might thus think of a routine trade-off in the case of a typical job dilemma. Faced with employment in Company A vs Company B, one might consider trading off mundane items such as salary, distance or working environment. On the other hand, an extreme (though commonplace) example of a tragic trade-off would be to decide whether to save one's parent or an offspring instead in the event of a fire.

In the first experiment, 84 students from the University of Zurich were presented with three scenarios representing a taboo, tragic or routine trade-off. Each scenario provided a choice between two options. An example of a taboo trade-off scenario was as follows:

Imagine that you are the president of the local authority of a village that has been severely affected by a flood. The local authority is discussing whether to invest a considerable amount of the annual budget in improved flood protection measures. In this case, however, the village would have to forego a planned facelift for the village square. As president, you have to decide between the improvements in flood protection (option 1) and the facelift for the village square (option 2).

Participants were then asked to rate how they felt about the decision, such as how emotionally negative the decision was and how difficult it was to decide on an option. The following results were gathered:

As can be seen, the difficulty of decision-making was lowest when sacred values were pitted against secular values, showing that, although decision-making involving some degree of moral choice is still emotionally unpleasant, it can lead to easier decision-making. A second experiment, which was a more complex (with multiple traits to access decision difficulty and affectiveness) but fundamentally similar experiment, was conducted and the results were replicated.

Tetlock (2003) had assumed that the mere contemplation of trade-offs that involve sacred values elicits distress and disturbance. There could very well be an adaptive or functional purpose to our negative perception of moral choices which makes us acutely aware that compromising on sacred values can have adverse consequences. In a sense, we are psychologically 'punished' for even contemplating the trade-off of sacred values, so let alone act against our instinct to preserve sacred values. These findings thus suggest that reliance on sacred values may therefore work as a heuristic that we use to increase the efficiency of our decision-making.

Martin Hanselmann, & Carmen Tanner (2008). Taboos and conflicts in decision making: Sacred values, decision difficulty, and emotions Judgment and Decision Making, 3 (1)

Tetlock, P. (2003). Thinking the unthinkable: sacred values and taboo cognitions Trends in Cognitive Sciences, 7 (7), 320-324 DOI: 10.1016/S1364-6613(03)00135-9

Existential Neuroscience

2011-02-13T18:38:00.000-08:00

Is it reasonable to fear death? If you agree with Lucretius, you will say no. In what is known as the Symmetry Argument, Lucretius contends that that the time before our existence is similar to the time of our future non-existence. And since we do not fear the time before we existed, it is not reasonable to fear our future non-existence i.e. death. (See Rosenbaum, 1989 for a more detailed exposition)

However, even if you concede to Lucretius’s argument, the fact remains that the awareness of our mortality generates a significant threat to our psychological well-being. A large corpus of research on terror management theory details how mortality saliency affects our self-esteem, worldview, among others.

In a recent fMRI study, Quilin and colleagues (2011) extends our knowledge on terror management theory by exploring the neural correlates of mortality salience. They were interested in the activity of the amygdala, rostral anterior cingulated gyrus (ACC), ventral tegmental & caudate nucleus (CN).

In this within-subjects experiment, thoughts of death were induced in the participants by requiring them to agree or disagree with a statement such as I am afraid of a painful death. Statements about dental pain were used in the control condition.

Results

The authors found higher activations in:

Right amygdala
Left ACC
Right CN

They suggested that the activations in the amygdala and ACC may indicate ‘non-conscious, latent markers of threat aroused by mortality salience’ and that further investigations may reveal the role of the CN in regards to the defensive mechanisms that we employ against mortality threat.

This area seems promising to me and more research needs to be done to help us better understand how we deal with threats of mortality. It would also be interesting to look at how religious affiliations affect the way the brain deal with existential fears. If indeed 'mortality threats functions as a potential for anxiety rather than as experienced anxiety', what can neuroimaging techniques tell us about whether believing in a higher being help us deal with the potential or experienced anxiety resulting from mortality threats?

Quirin M, Loktyushin A, Arndt J, Küstermann E, Lo YY, Kuhl J, & Eggert L (2011). Existential neuroscience: a functional magnetic resonance imaging investigation of neural responses to reminders of one's mortality. Social cognitive and affective neuroscience PMID: 21266462

Rosenbaum, S. (1989). The Symmetry Argument: Lucretius Against the Fear of Death Philosophy and Phenomenological Research, 50 (2) DOI: 10.2307/2107964

Beauty-is-Good Stereotype in the Brain

2011-01-26T03:08:00.000-08:00

Leo Tolstoy once said, “It is amazing how complete is the delusion that beauty is goodness.” And how complete is this delusion? In a recent study, Tsukiura & Cabeza (2011) provides an insight into this question by investigating the neural mechanism underlying the Beauty-is-Good stereotype. They were interested in the activity of the medial orbito frontal cortex (associated with positive stimuli, reward processing etc); the insular cortex (associated with negative stimuli, punishment processing etc) and the interaction between these two regions.

This fMRI study required participants to engage in 3 different tasks:

Face attractiveness rating (beauty judgment task)
Action goodness rating (moral judgment task)
Brightness rating (control condition)

The 3 tasks. Click to enlarge

Conforming to their hypothesis, the authors found that activity in the mOFC increased linearly as a function of both attractiveness and goodness rating. Activity in the insular cortex also decreased linearly as a function of both types of ratings. In both regions, the strong correlation between the activations caused by both judgments also supports the idea that similar neural regions are engaged when we are processing attractiveness and moral goodness.

Furthermore, the negative correlation between right mOFC and right insular cortex provides support for the “dual process hypothesis” of the Beauty is Good stereotype in that we display both a positive bias of attractiveness as being good and a negative bias against unattractiveness as being bad.

That is to say, the stereotype is driven by two opposing mechanism whereby we tend to think that an attractive person is more moral and an unattractive person is less moral, rather than a singular bias towards attractiveness or unattractiveness.

Click to enlarge

Our delusion that beauty is goodness then appears to have been built into how our brain processes both type of judgments and the completeness of this delusion may surprise even the great Leo Tolstoy.

Tsukiura T, & Cabeza R (2011). Shared brain activity for aesthetic and moral judgments: implications for the Beauty-is-Good stereotype. Social cognitive and affective neuroscience, 6 (1), 138-48 PMID: 20231177

When it's moving, it's hard to see it changing.

2011-01-13T04:19:00.000-08:00

Change blindness is a phenomenon whereby people fail to detect sizable changes in a visual scene. This can occur even when they are actively trying to locate the change (Simons & Ambinder, 2005). If you are unaware of this phenomenon, you can go to UBC's psychology department where they have some interesting video examples.

In a new study, Suchow & Alvarez (2011) demonstrates a novel visual illusion whereby motion induces failure to detect change - or what they call 'silencing'. Look at the video embedded below. Initially, the dots are visibly changing in colour but once the rotation begins, the dots appear to stop changing or at least appear to change at a slower rate. Additional video demonstrations looking at brightness, size and shape can be found here.

Motion silences awareness of color changes from Jordan Suchow on Vimeo.

They found that the faster the rotation, the slower the dots appear to change (i.e. stronger silencing).

Click to enlarge

In an additional set of experiments, they further determined that motion on the retina and not motion in space is responsible for silencing. Pretty nifty visual illusion huh.

*We are glad to have our first post based on a reader article submission and welcome additional submissions. Spread the word!

Suchow JW, & Alvarez GA (2011). Motion Silences Awareness of Visual Change. Current biology : CB PMID: 21215632
Simons, D., & Ambinder, M. (2005). Change Blindness. Theory and Consequences Current Directions in Psychological Science, 14 (1), 44-48 DOI: 10.1111/j.0963-7214.2005.00332.x

Birth Order Influences the Formation of Long-Term Relationships

2011-01-07T22:31:00.000-08:00

134 years since Francis Galton opened the birth order effects debate by observing that first-born sons and only sons were over-represented among English scientists, controversy has shrouded the issue such that we haven't quite gotten past whether birth order effects exist or not, let alone properly consider what they are or how they work.

Some scholars assert that the lack of conclusive evidence is due to methodological biases that may allow the researcher to find the result that he or she is looking for. So, in that sense, a researcher who seeks to confirm that the birth order effect exists may find it just as well as a researcher who seeks to disconfirm it might.

In Birth Order Effects in the Formation of Long-Term Relationships, Hartshorne, Salem-Hartshorne and Hartshorne seek to probe the birth effect in a manner that is as methodologically neutral as possible by simply determining if there are any correlations between the sharing of birth order and the likelihood of long-term relationship formation. Their results provide new research material that weighs in favour of the presence of birth order effects, though what drives this effect is still speculative.

By drawing on a sample of 900 US undergraduate students, the researchers found that people are more likely to form and be in long-term relationships, both friendly and romantic, if they share the same birth order than would be expected by chance. For instance, if I were a first-born child, the likelihood of me being close friends with another first-born child is higher than the likelihood of me being close friends with another second- or third-born child. This tendency was also found for romantic partners.

A second and similar web-based study was conducted which gathered responses from American participants (1,911) as well as participants from other parts of the world (713). Similar results were garnered. There was no significant difference detected between American and non-American respondents, suggesting that birth order effects on long-term relationships are not culturally variant.

The researchers also controlled for socioeconomic status and size of family, which is a progressive extension from other earlier studies. This eliminates the confounds of number of siblings one has and the socioeconomic class one belongs to, which can potentially influence one's development because it is a commonly known social phenomenon that wealthier and upper class families tend to have less offspring.

The authors surmise that birth order underlies personality traits and having the same birth order results in greater compatibility between personality types, leading to the formation of closer bonds in both friendships and romantic relationships.

Joshua K. Hartshorne, Nancy Salem-Hartshorne, and Timothy S. Hartshorne (2009). Birth Order Effects in the Formation of Long-Term Relationship Journal of Individual Psychology, 65 (2)

Detecting facial emotions: Women vs Men

2010-12-28T10:13:00.000-08:00

Do women really recognize facial emotion better than men? Existing literature on the subject remains contradictory with some studies showing a female advantage (albeit with small effect sizes) and others failing to find any gender differences. Hoffman and colleagues (2010) suggest that expression intensity is an important factor mediating gender differences in recognizing emotions and that while women do recognize facial emotions better than men, this advantage only exists for subtle emotional facial expressions.

Using a facial expression morphing tool (FEMT), they manipulated the intensity of the emotional facial expression for their stimuli. Looking at the 40% intensity, I must say that it is in fact pretty hard for me to identify.

click to enlarge

Conforming to their hypothesis, they found that women indeed only recognize subtle emotional expression better than men but not when full-blown emotions are displayed. Decreased emotional intensity negatively affected the judgments of male participants more than that of female participants.

But of course accurately detecting facial emotions is just the first part of the equation, whether you deal with it adequately is another thing altogether - especially when they are subtle.

Hoffmann H, Kessler H, Eppel T, Rukavina S, & Traue HC (2010). Expression intensity, gender and facial emotion recognition: Women recognize only subtle facial emotions better than men. Acta psychologica, 135 (3), 278-83 PMID: 20728864

Early Life Experience and Neurodegeneration

2010-12-02T04:53:00.000-08:00

Although some studies have found that early life environmental factors can affect our vulnerability to neurodegenerative diseases such as Alzheimer’s disease in later life, the underlying neuronal mechanisms of such vulnerability are not well understood. By looking at post mortem rhesus monkey brains, Merrill et al. (2011) finds an association between early life experience and subsequent risk of exhibiting neurodegeneration in later life.

In the study, β-amyloid plaque density and synaptophysin immunoreactivity in the brains of the rhesus monkeys that had lived in standard sized cages VS small cages (29% smaller than standard cages) for the first 15 years were compared. Young monkeys were also used as a basis for comparison.

β-amyloid plaque density

β-amyloid deposition has been established as the central cause of Alzheimer’s disease (Hardy & Allsop, 1991). The researchers found that monkeys that were housed in small cages had higher β-amyloid plaque density and amyloid load in the superior temporal gyrus compared to monkeys that were housed in standard sized cages. Young monkeys had no detectable amyloid deposition and were not graphed.

click to enlarge

However, I think the β-amyloid density results should be taken with a pinch of salt. Although the authors did mention that there is considerable individual variation - which parallels data in human studies, the effects seemed to be heavily driven by the monkey which had almost 140 plaques per mm square. Also, there were only 5 monkeys in the small cage condition and 3 of them appear to have comparable β-amyloid density levels. The authors also did not include individual data for the superior temporal gyrus amyloid load graph but the large error bar again suggests significant individual variations.

Synaptophysin Immunoreactivity

Monkeys reared in small cages also showed a reduction in synaptophysin immunoreactivity - a presynaptic marker, in the superior temporal gyrus. This indicates a decrease in synaptic density and activity which has been linked with cognitive impairment in Alzheimer's disease.

All said, the value of the study lies in their finding “early life experience is associated with degenerative change in the non-diseased aged brain” (emphasis theirs). Therefore, even in normal aging, our early life experiences can affect the rate of neural degeneration. Remind me to get a bigger crib for my child in the future.

Merrill DA, Masliah E, Roberts JA, McKay H, Kordower JH, Mufson EJ, & Tuszynski MH (2011). Association of early experience with neurodegeneration in aged primates. Neurobiology of aging, 32 (1), 151-6 PMID: 19321231

Effects of sleep on Remembering to Remember

2010-11-17T23:13:00.000-08:00

Prospective memory is a class of memory that is unique in that it involves the future rather than the present or the past. Various examples of prospective memory include remembering to buy a pet monkey, or remembering to break up with your girlfriend or remembering to do that blasted thesis that you have been putting off for the umpteenth time. Hence, some researchers have called it the act of "remembering to remember" (Winograd, 1988). Although prospective memory is quite important for daily functioning and goal fulfilment, research on it has been quite sparse in comparison to other forms of memory. One big question remains: how do we remember to remember? Do we devote some resources to maintain this intention? Or is it maintained without anything being devoted to it?

You know you want it.

One theory of prospective memory suggests that prospective memory can be both effortful and automatic. One way in which prospective memory can be automatic is when cues in our environment alert us to something we have to do. Kvavilashvili and Fisher (2007) has found that individuals often encounter cues related to a goal (eg, seeing a monkey in the magazine, receiving a text message from the girlfriend) and these cues spontaneously remind participants of their goal. Another way in which prospective memory is maintained is through conscious retrieval. Other researchers have also found that prospective memory surprisingly is better after 15 minutes than 3 minutes, one interpretation being that participants consciously retrieve and rehearse the goal prior to and up to the point when they are going to execute it (Hicks, Marsh & Cook, 2005).

One question that arises from these findings is that, what happens when we sleep on something? During sleep it appears that both automatic and effortful mechanisms are absent; we don't consciously retrieve and rehearse goals, and we aren't exposed to cues from the external environment. In such a case we might expect that prospective memory would weaken. However, given that a huge amount of literature has also shown that sleep improves memory, we might expect that sleep would improve prospective memory. These contradictory hypotheses form the basis for Scullin and McDaniel's study, "Remembering to execute a Goal: Sleep on it!" (2010)

The researchers had participants do a series of tasks (too lengthy to cover), while remembering to do a particular action at a particular time ("press the Q key when you see the word table or horse"). In one set of participants, this target came after a short delay (20 minutes) while in the long delay condition, participants were told to come back after 12 hours for another series of experiments and the target came there. The other crucial manipulation was time of day, the experiment for one set of participants was started in the morning, and the other set at night. The study was between groups, so participants were spread out across 4 conditions.

1. Short Morning Delay

2. Short Evening Delay

3. Wake Delay (from morning to night, during which time the participant was awake)

4. Sleep Delay (from night to morning, during which time the participant was sleeping)

What the researchers found was that sleeping improved the ability to remember to do something, as compared to being awake. In some of the tests, the performance was almost as good as if one was tested after 20 minutes. One important possible confound in this experiment was that the sleep and awake conditions also differed not just in amount of sleep but also when the experiment was conducted. The authors eliminated this confound by comparing performance for prospective memory during the day and night after a short delay and found that time of day had little effect.

So the results are inconsistent with the idea that sleep might undermine prospective memory by preventing conscious retrieval or exposure to environmental stimuli. It seems like prospective memory might not rely heavily on these 2 processes, as suggested by some proponents of the theory above. The implication being that if you need to remember to do something, you might as well sleep on it.

But how does sleep improve prospective memory? The authors suggest that sleep increases associative binding and that it amplifies weak goals or links. In this case, it seems like prospective memory might not be very much different from other types of memory. However the authors find that sleep improves prospective memory for only certain types of tasks, thus raising new avenues for research into different kinds of prospective memory and how they are affected by different variables.

One problem which I found in this paper was that the participants were engaging in quite an unnatural prospective memory task, in which case environmental cues present during the awake phase would not help the participant in remembering to do the task. On the other hand, in the real world, such environmental cues would be present and abundant (like seeing your thesis supervisor). So in that sense, the authors can't make the claim that sleeping improves prospective memory more than staying awake and being exposed to constant pictures of monkeys.

Another interesting idea that this paper raises is the implication of sleep on prospective memory in old people. It has been found that prospective memory is one memory that is especially impaired and gets worse with old age (they keep forgetting to get the groceries for instance). Old people also get less sleep, especially sleep of the slow wave kind. Coincidence? :)

Scullin MK, & McDaniel MA (2010). Remembering to execute a goal: sleep on it! Psychological science : a journal of the American Psychological Society / APS, 21 (7), 1028-35 PMID: 20519489

Jealousy, Turning Saints into the Sea?

2010-11-13T18:59:00.001-08:00

"Not so long ago jealousy was considered a pointless, archaic institution in need of reform. But like other denials of human nature from the 1960s, this bromide has not aged well. ... The rock musician who wrote 'If you love somebody set them free' also wrote 'Every breath you take, I'll be watching you.'"

- Steven Pinker, on David Buss's The Dangerous Passion

Have you ever felt threatened in the presence of others you perceive to be superior to you? I recall one time when I was a teaching assistant in an introductory psychology course and, in the middle of a discussion about how jealousy is experienced when your partner interacts with someone else who appears to have higher mate value than you, an eager student asked, “Professor, but how do you know if that person has a higher mate value than you?” To which the professor smiled and cheekily said, “Oh, you just know.”

To humour the bemused student, the professor gave some scenarios. If you’re a guy, just imagine this. Some other socially dominant male is talking to your girlfriend or wife, and he’s trying to make her laugh. Worse, she actually laughs along and looks like she’s having a very comfortable and enjoyable time. If you’re a lady, imagine the reverse – your boyfriend or husband has met a younger and physically attractive woman, and now he’s the one trying to make her laugh, and she’s playing along and being very reciprocative. That creeping feeling of alarm bells and jealousy becomes just a tad more resonant.

In the dating and mating game, what exactly are those social cues that get us to be on our guard, to experience inferiority and to feel threatened? Gutierres, Kenrick and Partch (1999), researchers looking at the issue through an evolutionary perspective, explored the oft-cited mating preferences of men for physical attractiveness and women for status and social dominance, and elucidated interesting sex differences in contrast effects.

The researchers gathered data from 91 undergraduate females and 99 undergraduate males and primed the men with either physically attractive men or socially dominant men while, on the other hand, priming the women with either physically attractive women or socially dominant women. Exposure to physically attractive men or women was done by showing participants photographs of people, while exposure to socially dominant men or women was done by getting participants to read a descriptive profile of a person with high dominance.

Interestingly, their study found that men’s self-assessments of desirability were adversely affected by exposure to highly socially dominant men and were relatively unaffected by exposure to physically attractive men. Conversely, women’s self-reports of their mate value were more affected by the physical attractiveness than by the social dominance of the women to whom they were exposed. This demonstrated that humans are sensitive to the selective mate preferences of the opposite gender. If we consistently fail to match up to the quality of our rivals, this can have an effect on how we perceive our own desirability!

More recently, another set of experiments conducted by Maner, Gailliot, Rouby and Miller (2007) also looked at how our state of mind affects the level of attention we give to stimulus objects in our environment.

A total of three studies were done on undergraduate students to explore how this interacts in the scene of human mating. It was found that when participants were primed with feelings of romantic and sexual arousal, a ‘mate-search’ psychological mechanism was activated which resulted in greater attentional adhesion* towards attractive members of the opposite sex. On the contrary, when participants were evoked with feelings of jealousy (imagining a scenario that perhaps closely resembles the one that the professor had painted), a ‘mate-guard’ state of mind was primed which led to greater attentional adhesion to attractive same-sex targets.

So is jealousy simply a manifestation of insecurity? Perhaps the answer is both yes and no. Yes, because it does seem apparent that the mind is designed to experience jealousy when the environment provides feedback on where you stand. If there are many people of the same sex as you in the room who are far more attractive, that’s good reason to feel insecure especially when being evaluated by members of the opposite sex. But jealousy isn’t only just a manifestation of insecurity because it serves an important adaptive function – to alert us to the potential dangers of losing your mate, telling us to be aware of snakes and wolves in the environment, and getting us to turn on our A-game where necessary. As David Buss writes in The Dangerous Passion, jealousy is as necessary as love and sex.

* Attentional adhesion refers to how readily a person tends to a particular stimulus. In most documented cases, this is determined by measuring participants' reaction time taken to respond to stimulus.

Maner JK, Gailliot MT, Rouby DA, & Miller SL (2007). Can't take my eyes off you: Attentional adhesion to mates and rivals. Journal of personality and social psychology, 93 (3), 389-401 PMID: 17723055

Gutierres, S., Kenrick, D., & Partch, J. (1999). Beauty, Dominance, and the Mating Game: Contrast Effects in Self-Assessment Reflect Gender Differences in Mate Selection Personality and Social Psychology Bulletin, 25 (9), 1126-1134 DOI: 10.1177/01461672992512006

Buss, D. M. (2000). The Dangerous Passion: Why Jealousy Is As Necessary As Love and Sex. New York: Free Press.

Racial Differences in the Concept of Beauty

2010-10-25T01:11:00.000-07:00

Are average composite faces the most attractive faces or are highly attractive faces markedly different from average faces? Rhee & Lee (2010) agrees with Perrett & Yoshikawa (1994) that the most attractive face is actually the average of attractive faces and that an average face; while attractive, is not the most attractive.

They also argue that previous concepts of beauty such as the divine proportion (golden ratio) are not a good measure of beauty across different races and should not be used as an overarching universal indicator of beauty. Between different races, there appears to be different characteristics that are deemed beautiful. They merged some of the most attractive female faces of African, Caucasian, Chinese and Japanese people respectively, to create the images below.

They also mentioned some of the defining characteristics of beauty for the different races.

African: Narrow nose, smaller and more acute eyes, smaller upper lip, slender chin compared to the average African face.
Caucasian: Somewhat masculine, narrow palpebral (eyelids) height, angulated and squared mandible (lower jaw), protruding cheek and fuller lips compared to the average Caucasian face.
Chinese: Narrow cheek, slim and thin face, lantern jaw.
Japanese: relatively longer face, slightly slanted eyes, sharp chin and chubby cheeks.

Unfortunately, they did not conduct any experimental study to compare attractiveness ratings of such faces versus other faces that are considered beautiful based on traditional morphometrics. It would also have been interesting to look at how the male composite faces would look like.

Rhee SC, & Lee SH (2010). Attractive Composite Faces of Different Races. Aesthetic plastic surgery PMID: 20953953

Perrett DI, May KA, & Yoshikawa S (1994). Facial shape and judgements of female attractiveness. Nature, 368 (6468), 239-42 PMID: 8145822

The link between coffee and acute ischemic stroke onset

2010-10-14T10:10:00.000-07:00

Do you drink coffee on a regular basis? I do. And what does drinking coffee have to do with acute ischemic stroke (caused by disruption of blood supply to part of the brain)? In a study published in Neurology, Mostofsky and colleagues investigated the relationship between drinking caffeinated coffee and the risk of acute ischemic stroke in the next hour.

Using a case-crossover design, each subject served as his/her own control. All the subjects were patients with a confirmed diagnosis of ischemic stroke. Coffee consumption information one hour before the onset of stroke symptoms was compared with their frequency of coffee consumption in the previous year.

They found that drinking coffee doubles your risk of ischemic stroke onset in the next hour compared to drinking other caffeinated drinks such as tea or cola; which may be due to lower concentrations of caffeine in those drinks.

When they looked at the frequency of caffeinated coffee intake in the previous week, they found that only people who were drinking ≤1 cup of coffee per day had increased risk for ischemic stroke in the following hour.

The take-home message?

Drinking coffee temporarily increases one’s risk of ischemic stroke – especially so for infrequent drinkers (≤1 cup of coffee per day).

Well, I don’t think I’m willing to forsake my coffee just yet so I’m going to have 2 cups a day instead of my usual 1 a day.

Mostofsky E, Schlaug G, Mukamal KJ, Rosamond WD, & Mittleman MA (2010). Coffee and acute ischemic stroke onset: The Stroke Onset Study. Neurology PMID: 20881275

What the Presence of Attractive Young Women can do to Men

2010-10-05T11:08:00.001-07:00

Much has been said about the female preference for resources and the male preference for physical attractiveness, but at the time of James R. Roney's (2003) writing little had been done to tease out cognitive mechanisms that underlie this adaptive preference.

Roney thus set out to ascertain the ability of ecological cues to prime and activate psychological constructs related to mate attraction and establish linkages between human mating and social cognition.

In his first study, participants - young students from the 10th and 12th grades of a Midwestern high school - were made to answer three large booklets of surveys. However, the manipulation of the environment within which the surveys were answered was as follows: in the first condition, all participants were male; in the second condition, all participants were female; in the last condition, males and females were present during the study. Without knowing what the experimenter was up to, participants answered questions in the surveys, and nested in those surveys were questions related to one's attitudes towards wealth and resources.

The results fascinatingly appear to support evolutionary theories about human mating. Male students in the mixed-sex environment reported higher valuations of material wealth than did male students in the same-sex environment.

The young men in the mixed-sex condition also reported higher ratings of having an active dating life. These findings suggest that the presence of females may have primed implicit mate attraction goals and, subsequently, the activation of cognitive attitudes associated with mating objectives (detailed manipulation checks were conducted via cleverly placed questions on items such as current relationship status and mate preferences, reducing the possibility of confounding variables).

Now that the first experiment appears to be consistent with evolutionary theory predictions, Roney sought to find out if other mating goal-related attributes in men can be primed. In his second study, male participants were exposed to advertisements featuring either younger female models or older female models, after which they filled out a questionnaire.

The results again confirm evolutionary theory hypotheses - men in the younger models condition reported higher valuations of wealth (replicating the findings of the first study), had a greater desire to display/showcase talent and, interestingly, listed self-descriptive traits that increase men's odds of attracting women (this was confirmed through separate ratings of the male participants' self-descriptive traits by women), such as ambitiousness and aggressiveness.

Roney's study thus brings evolutionary psychology one step further by utilizing ecologically realistic stimuli, in the process demonstrating powerful but previously unknown psychological effects. Specific to this study, visual exposure to young women caused significant changes in the attitudes and personality trait descriptions of the young male participants. In particular, young men who were exposed to young women reported far more favourable attitudes towards material wealth than did men exposed to either other men or older women.

This makes sense because if securing a mate was an important task in ensuring the survival of one's lineage (without which those of us alive today wouldn't be here), then there should be psychological mechanisms present to facilitate the achievement of such goals, and men should thus be sensitive to cues that relate to both potential mates and resources. Using an adaptive basis for understanding psychology can also prove useful, because without this evolutionary context of mating, such stable behavioural changes demonstrated in Roney's study can, at best, only appear random and lead to invalid conclusions.

Roney, J. (2003). Effects of Visual Exposure to the Opposite Sex: Cognitive Aspects of Mate Attraction in Human Males Personality and Social Psychology Bulletin, 29 (3), 393-404 DOI: 10.1177/0146167202250221

Is eating 6 meals a day instead of 3 a better weight loss strategy?

2010-09-25T09:53:00.000-07:00

I’ve come across a significant number of non-peer reviewed articles on the internet about weight loss, body building etc. that advocates eating 6 meals a day (just Google "3 meals or 6 meals" to see what I mean). Reasons given for doing so includes less fluctuation in blood glucose and lower fat storage among others. But is eating 6 meals instead of 3 a day really beneficial for someone trying to cut some flab? Some researchers think not.

In an article published in Obesity, Leidy and colleagues (2010) investigated how differing amount of dietary protein and eating frequency influences our perceived appetite and satiety levels during weight loss.

In a 12 week experiment, 27 obese men were randomized into either the high protein or normal protein group and were required to engaged in a weight-loss diet that is 750kcal/day lower than their daily needs. Beginning on the 7^th week, all participants alternated between 3 meals a day or 6 meals a day, each lasting for 3 days. Information on their perception of daily hunger, desire to eat and thinking about food were recorded and compared.

Results

The high protein group felt fuller, had lower desire to snack at night and thought less about food than the normal protein group.
Eating 3 or 6 meals a day did not have any effect on hunger, fullness, desire to eat nor preoccupation with thoughts of food.

The take-home message? Getting on a high protein diet appears to be a viable weight loss strategy because it gives you better control over your appetite and satiety but switching to a 6 meals a day strategy appears not to be helpful in these areas.

Furthermore, some previous studies have found a relationship between higher meal frequency and higher colon cancer risk (eg. Shoff et al, 2000 (for women), Wei et al. 2004(for men)). So I were you, I'll think twice about adopting that 6 meals a day plan too readily.

Leidy HJ, Tang M, Armstrong CL, Martin CB, & Campbell WW (2010). The Effects of Consuming Frequent, Higher Protein Meals on Appetite and Satiety During Weight Loss in Overweight/Obese Men. Obesity (Silver Spring, Md.) PMID: 20847729
Wei, J., Connelly, A., Satia, J., Martin, C., & Sandler, R. (2004). Eating Frequency and Colon Cancer Risk Nutrition and Cancer, 50 (1), 16-22 DOI: 10.1207/s15327914nc5001_3
Shoff, S., Newcomb, P., & Longnecker, M. (1997). Frequency of eating and risk of colorectal cancer in women Nutrition and Cancer, 27 (1), 22-25 DOI: 10.1080/01635589709514496

Spicy food and collectivism: How the brain shapes culture

2010-09-18T10:19:00.000-07:00

We are used to thinking of culture as a social factor and not a biological factor. We attribute dispositions such as being individualistic or being collectivist to the country that one was brought up in, but no one has really looked into why certain cultures tend to be that way. An emerging field of research called cultural neuroscience says that cultural values can be shaped by the brain and genes.

For example, in one striking example I read about quite recently, one hypothesis put forth for the reason why Asian people like spicy food was because spices conferred natural bacteria killing properties that was especially important in a humid climate where food went bad. Over time, the hypothesis goes, people who liked spicy food more and ate more spicy food were less prone to stomach diseases that killed the others, thus passing on their genes for the next generation. A similar finding was found when examining lactose intolerance. Lactose intolerance is far more prevalent in certain regions of Asia where the rearing of lifestock for milk is less common. In Europe however, up to 95% are able to digest lactose, and this is reflected in their preference for milk products like cream and cheese.

In this review by Way and Lieberman, they sought to answer the question as to why certain cultures tend towards individualism and collectivism. They reason that because of evolution, genes that change brain function and influence the cultural norms we adopt and we institute are selected for between people born in different regions. For people brought up in one region that was say marked by famine, grouping together and helping one another might have brought about greater survival for the people, hence the genes that promote this thinking get passed on. In a separate part of the world, marked by conflict perhaps, survival would favor people who think for themselves and for their immediate family members. Over time, those different selective pressures would have promoted different social behaviors in different regions.

What mechanisms might have promoted these behaviors? They reviewed work from scientists studying the distribution of several genetic alleles. Previous work has shown that variation in the serotonin transporter gene, a very important neurotransmitter associated with emotion and reward, was associated with individual differences in social sensitivity. People with the short version show greater reaction to social events such as death or birth of children, regardless of whether it was positive or negative. When these scientists studied the distribution of these alleles in different cultures, surprise surprise! They found that the short version of this allele was much more prevalent in collectivist cultures than individualist cultures.

*higher score on individualism collectivism scale indicates higher individualism.

The authors hypothesize that since this allele makes people more sensitive to being socially excluded, it promotes individuals to tend and befriend, leading to a cultural trend of being more collectivist. There's more to read about other such alleles in the review, but seeing as to how this post is quite wordy already, I'll stop here :)

Sherman, P., & Billing, J. (1999). Darwinian Gastronomy: Why We Use Spices BioScience, 49 (6) DOI: 10.2307/1313553

Way, B., & Lieberman, M. (2010). Is there a genetic contribution to cultural differences? ... SCAN, 5 (2-3), 203-211 DOI: 10.1093/scan/nsq059

Why does Time Slow to a Crawl when we Engage in Laborous Tasks?

2010-09-08T21:09:00.000-07:00

"Put your hand on a hot stove for a minute, and it seems like an hour. Sit with a pretty girl for an hour, and it seems like a minute."

- Albert Einstein, on Relativity.

Kathleen Vohs and Brandon Schmeichel, particularly fascinated with Einstein's first observation, sought to establish whether regulating the self can elongate the 'felt' duration of time. "Because people who are self-regulating tend to monitor their behaviour, they are likely to be attuned to the passage of time," explain the authors, "these monitoring responses and resultant attention to time are not found among people who are not regulating."

In simpler terms, 'self-regulation' is likely to be linked with the attention to time. In earlier studies on duration judgment, when participants were asked after watching a TV episode to estimate the length of the episode, they gave shorter time estimates than participants who were told that they had to guess the duration of the episode prior to watching it. It appears that conscious deliberation, as opposed to the non-regulated state of automatic processing, might lead one to be more aware of time passing.

Thus, hypothesizing that deliberate, conscious and effortful self-regulation would lead one to feeling like time has passed slowly, Vohs and Schmeichel conducted four illuminating studies that lent scientific support to the claim.

In Study 1, the authors made participants watch a clip from the film Terms of Endearment, which shows a dying mother saying good-bye to her children, husband and mother. Participants were made to either naturally respond to what they saw, or suppress their emotions or exaggerate their emotions while watching the show. This manipulation had been found in earlier studies to be effective in causing participants to consciously regulate their emotions which led to diminished self-control capacity.

Participants were instructed to estimate the length of the video clip after the 11 min 23 sec clip ended.

It was found that participants who exaggerated or suppressed their emotions perceived that the film clip had lasted longer than participants who were natural during the film.

In Study 2, a similar experimental set up was used, although the film was changed from Terms of Endearment to Mondo Cane (depicting the death of wildlife). To determine that longer judgments of time were due to self-regulation specifically and not generic information processing, a new condition called 'reappraisal' was introduced. Participants in the reappraisal group were instructed to view the affectively-charged scenes in a detached manner. The authors explain: "Prior studies have shown that effects associated with emotion control (e.g. memory decrements because of emotion suppression) are absent when participants are given a reappraisal framework within which to view an emotional scene."

Participants were, again, then asked to judge how long the clip lasted.

The results support the idea that the Natural and Reappraisal conditions, which did not require self-monitoring, did not prompt the attention to time that was present in the Suppress condition.

In Study 3, participants were told to read aloud pages of text that corresponded to various types of professions. In the behavioural control group, participants were instructed to 'act out' the profession as depicted by the text, and thus they had to do their best to "act happy, smile and 'get into it'" as expected of the profession. Participants in the no condition group weren't given any such instructions.

After 4 minutes and 23 seconds had passed, participants were interrupted with a questionnaire asking them how long they thought the experiment had lasted. After that, participants were told that they could continue up to a cap of 15 minutes and stop at anytime in between.

Once again, the findings of the first two studies were replicated in the results of Study 3 as participants in the behavioural control group felt that they spent a longer time doing the task than participants in the no condition group. Continuance of the task was also affected by the manipulation, as "the longer participants believed they had been doing the read-aloud task, the shorter they continued with it after the 4:23 mark."

From this, the authors built a model that linked the experimental conditions and subsequent regulatory ability.

The results of this model were supportive of the hypothesis that time perception is a mediator. This model was further supported by a final study.

Thus, across four experiments, the authors found that people's perceptions of the duration of an activity were significantly affected by self-regulatory resource depletion. Whenever some form of cognitive regulation is involved, for instance, emotion regulation or self regulation, people can believe that the task involved lasted much longer. "A taxing self-regulatory activity is remembered as being overly long."

Where Einstein's latter observation is concerned, it might thus be likely that sitting with an attractive member of the opposite sex constitutes a very enjoyable process that requires less self regulation, which makes us less conscious of the passage of time. So, where does this place those who experience anxiety approaching attractive members of the opposite sex?

Vohs, K., & Schmeichel, B. (2003). Self-regulation and extended now: Controlling the self alters the subjective experience of time. Journal of Personality and Social Psychology, 85 (2), 217-230 DOI: 10.1037/0022-3514.85.2.217

How to improve your cognitive function

2010-08-29T08:10:00.000-07:00

In an era of ever increasing lifespan, a recent study estimated that there would be 81.1 million people with dementia by 2040 (Ferri et. al., 2005). The prevalence and incidence of dementia has also been documented to increase with increasing age (Fratiglioni, Ronchi & Agüero-Torres, 1999).

Abraham Lincoln in his infinite wisdom, once said: “In the end, it's not the years in your life that count. It's the life in your years”. So what can we do to enhance our cognitive functions as we age?

The link between exercising and cognitive health is an area of intense research but some questions remains unanswered. What component of cognitive functioning does exercise improves and how much does the quantity of exercise affect any subsequent increase in cognitive functions? Masley, Roetzheim & Gualtieri (2009) provides some answers.

Participants were classified into 3 conditions for a 10 week intervention programme.

Control (0 – 2 days/week of aerobic activity)
Moderate (3 – 4 days/week of aerobic activity)
Intense (5 – 7 days/week of aerobic activity)

They were administered with a set of computerized battery tests that examined their performance on 5 domains – memory, psychomotor speed, information processing time, attention and cognitive flexibility. After a 10 week exercise programme intervention, they were required to complete the test again and their pre and post treatments scores were compared.

Results:

After controlling for demographic factors such as age, gender and education, only cognitive flexibility (a measure of executive function) improved significantly.
There was a positive relationship between amount of exercise and improvements in cognitive function. The more you exercise, the larger the increase in executive function.

So what are you waiting for? Go get yourself some aerobic exercise (preferably in a natural environment) because interaction with a natural environment as opposed to an urban environment has also been shown to improve cognitive functions. (Berman, Jonides & Kaplan, 2008)

Masley S, Roetzheim R, & Gualtieri T (2009). Aerobic exercise enhances cognitive flexibility. Journal of clinical psychology in medical settings, 16 (2), 186-93 PMID: 19330430

Berman, M., Jonides, J., & Kaplan, S. (2008). The Cognitive Benefits of Interacting With Nature Psychological Science, 19 (12), 1207-1212 DOI: 10.1111/j.1467-9280.2008.02225.x

Ferri, C., Prince, M., Brayne, C., Brodaty, H., Fratiglioni, L., Ganguli, M., Hall, K., Hasegawa, K., Hendrie, H., & Huang, Y. (2006). Global prevalence of dementia: a Delphi consensus study The Lancet, 366 (9503), 2112-2117 DOI: 10.1016/S0140-6736(05)67889-0

Fratiglioni, L., De Ronchi, D., & Ag??ero Torres, H. (1999). Worldwide Prevalence and Incidence of Dementia Drugs & Aging, 15 (5), 365-375 DOI: 10.2165/00002512-199915050-00004

Becoming a Better Person: The Good, the Bad, and the Past

2010-08-17T10:06:00.000-07:00

When we think of ourselves as being morally good or morally bad, what goes on in our brains? What moral memories does our mind gather to affirm that we are one or the other, and how are these memories influenced by cognitive biases?

In some ways, we are already aware of some cognitive biases in the way we remember events. For example, we know of an "emotional bias" where emotional memories are remembered more vividly, are typically easier to retrieve and seem more familiar, even when the actual memories are not typically accurate. There also appears to be a"positivity bias" in that positive memories tend to be more vivid then negative ones and are less easily forgotten.

Not much research has been done on moral memories and given that moral memories are often emotional ones (cheating on a partner for instance, or helping someone and receiving their gratitude in turn), similar cognitive biases might exist. In this study, the authors hypothesize that we would remember ourselves doing good deeds more recently, a sort of "temporal bias".

The authors collected 700 autobiographical moral memories and characterized them on 3 categories of good versus bad. They also measured how long ago these events took place and collected data on possible contributing factors like gender, IQ, personality, etc. They then compared the mean age of the morally good memories to the morally bad memories and found that the morally good memories were always more recent.

What could drive these findings? The authors list 3 distinct and fascinating possibilities.

1) People actively reconstruct their memories to render their most recent acts, the acts to which one is most accountable, in a more positive light and relegate bad deeds to the distant past where one can come up with a host of reasons like "I was young" or "I didn't know better". This would be a real "temporal bias".

2) Perhaps bad decisions are more emotionally arousing and hence are remembered better (refer to "emotional bias" above) and their memories, older.

3) There is some real difference in the way people act when they are younger and when they older, so they remember their older self as being more morally good while their younger self as being morally bad. This would be a non-psychological explanation for the phenomena examined above.

While I think the study does indeed have several flaws that makes it hard to disentangle the possibilities, the idea it raises is quite exceptional. The way I interpret it is that, for the most part, we always strive to be better people, but we can never forget the wrongs that we have done. The solution that the brain seems to have evolved, if the authors are correct, is to relegate the ugly deeds to the past, and push the good to the present.

Escobedo, J., & Adolphs, R. (2010). Becoming a better person: Temporal remoteness biases autobiographical memories for moral events. Emotion, 10 (4), 511-518 DOI: 10.1037/a0018723

Cognitive Inferences and Optical Illusions

2010-08-14T02:33:00.000-07:00

Ever wondered what allows us to be so perceptive about the world around us that it's almost taken for granted? Or why it is so difficult to create a robot with human-like perception, intelligence and understanding?

The discovery that the brain forms assumptions about the world in order to facilitate our lives has been one of the most illuminating insights from psychology and neuroscience.

Assumptions, or cognitive inferences, are what separates humans from robots. One very salient instance of this is our ability to see a man and his shadow against a wall, and not perceive that there is actually another physical object next to the man. Robots need to be programmed an infinite number of rules to overcome just this problem which our brain easily solves by utilizing assumptions that have been formed based on our experiences and through learning

One very interesting way of teasing out these assumptions is by means of optical illusions. Optical illusions fool us because they violate our assumptions about what we see. A really good one I'd recommend is this illusion by Edward H. Adelson.

What is special about this, you might ask? Well, Tile A and Tile B are objectively the same colour.
Look again. It might be hard to believe at first, but it really is!

And to prove it (I couldn't believe it myself initially), I did the following. I created a brownish-green oval, copied it so that there are exactly two same coloured ovals, and shifted them into the tiles.

Amazingly, the two ovals appear different accordingly.

To shortcut the process above, here's probably what's going on.

The bar in the middle is really a uniformly grey bar.

What's happening is that our mind cannot divorce the effect of shadows from our perception. As long as the picture shows the green cylinder casting a shadow, the 'shadow assumption' module of our brains gets activated and the things in relation to it will be affected. A robot should typically see Tiles A and B to be the same.

Our assumptions fill in the gaps so that our perception of the world becomes seamless and efficient (and it doesn't feel like we're constantly bombarded with stimuli).

Adelson, E. (1993). Perceptual organization and the judgment of brightness Science, 262 (5142), 2042-2044 DOI: 10.1126/science.8266102

Adelson, E. (2001). On seeing stuff: The perception of materials by humans and machinesHuman Vision and Electronic Imaging VI, Bernice E. Rogowitz; Thrasyvoulos N. Pappas, Editors, pp.1-12

What should you spend on to maximize your happiness?

2010-08-07T02:03:00.000-07:00

When it comes to spending our money, we instinctively think that we will derive the most happiness by spending it on ourselves, regardless of whether it is to pay that pesky bill, or buy ourselves a nifty new gadget or that gorgeous handbag that we have been eyeing for ages. But is spending money on ourselves really the best way to boost our happiness, or is there something more to it? Dunn, Aknin & Norton (2008) provide some unexpected insights.

The researchers hypothesized that, compared to spending money on ourselves, spending money on others will actually make us happier. 632 Americans were asked to rate their happiness, indicate their annual income and also estimate how they spend their money in a month, which was subsequently categorized into Personal Spending & Prosocial Spending.

Results:

Personal Spending (Bills & expenses, Gifts for themselves) was not a significant predictor of happiness.
Prosocial Spending (Gifts for others, Donations to charity) was a significant predictor of happiness.

The authors proceeded to extend their study to investigate whether people who received a windfall would be happier if they had spent it on themselves or on others. The windfall here refers to a profit-sharing bonus for 16 employees in a company. They were asked to rate their happiness 1 month before (Time 1) getting the bonus and after 6-8 weeks (Time 2). Participants were then asked to estimate how they spent the bonus, which was also subsequently categorized into Personal Spending & Prosocial Spending.

Results:

Personal Spending (Bills & expenses, Rent or mortgage, Buying something for themselves) was not a significant predictor of happiness at Time 2.
Prosocial Spending (Buying something for someone else, Donating to charity, Other) was a significant predictor of happiness at Time 2.
They also found that how the participants spend the bonus was more important than the size of the bonus.

In order to establish a causal relation using an experimental methodology, the researchers gave participants either $5 or $20 and were instructed to either spend it on themselves (Personal Spending) or to spend it on others (Prosocial Spending).

Results:

Participants who were in the Prosocial Spending condition reported greater happiness than participants who were in the Personal Spending condition.
The size of the money ($5 or $20) did not have a significant effect on happiness.

So how can we make use of these findings to maximize our happiness by deciding on what we should spend on?

In sum:

Allocate some of our spending on others (Gifts, donations etc.).
The sum does not have to be big, even an amount of $5 when spent in a prosocial manner can result in significantly higher happiness levels.
We can make ourselves happier than a person with a bigger bonus by simply tweaking how we spend our cash.

Dunn, E., Aknin, L., & Norton, M. (2008). Spending Money on Others Promotes Happiness Science, 319 (5870), 1687-1688 DOI: 10.1126/science.1150952

How to maxmize your happiness from a vacation.

2010-07-24T07:31:00.000-07:00

I am sure that most, if not all of us would agree that going on a vacation makes us happy. But are we really happier than people who are not going for a holiday? And if we are indeed happier, how long do these effects persist and how does the length of our vacation and amount of holiday stress impact our happiness levels? These are some of the questions that Nawijn, Marchand, Veenhoven & Vingerhoets (2010) attempt to answer.

Their main findings are listed below.

Pre-trip happiness: Vacationers (n=974) displayed significantly higher degrees of happiness than non-vacationers (n-556)
Post-trip happiness: Vacationers were generally not significantly happier than non-vacationers. Only vacationers who rated their holidays as very relaxed (as opposed to relaxed, neutral, stressful or very stressful) had significantly higher degrees of happiness for the first 2 weeks after the vacation.
Length of vacation was not associated with post-trip happiness.

*Note: The vacation began between week 27 and week 35.

So what do these findings tell us about how we should plan our vacations?

For starters, the planning and anticipation of the upcoming vacation makes us much happier folks than those who are not looking forward to a vacation.

The second finding, in line with the set point theory of happiness, indicates that once we are back from a vacation, our happiness returns rapidly back to baseline levels. Only the 'very relaxed' vacationers get an additional 2 weeks boost of happiness. So if you want that extended endorphins kick, make sure that you are really relaxed during the vacation.

The last finding, together with the first two findings, suggests that in order to derive the most happiness out of your vacation, it would be better to take multiple short trips rather than a long trip. Since the length of the vacation is not associated with happiness, you'll get the most bang for your buck by enjoying the pre-trip happiness generated from planning and anticipating multiple trips.

In sum:

Enjoy the planning process
Do your best to make your trip very relaxing (a trip that is just 'relaxed' doesn't quite cut it)
Multiple short trips are better than one long trip

Nawijn, J., Marchand, M., Veenhoven, R., & Vingerhoets, A. (2010). Vacationers Happier, but Most not Happier After a Holiday Applied Research in Quality of Life, 5 (1), 35-47 DOI: 10.1007/s11482-009-9091-9

Boost your Guitar Hero skills 101 - SLEEP! Really?

2010-07-16T02:25:00.001-07:00

We have been told that feeling well-rested while studying and reviewing your work just before bedtime enhances your memory for what you have studied. But when it comes to the role of sleep in motor memory, the answer is less clear. A recent research abstract presented at the 24th annual meeting of the Associated Professional Sleep Societies LLC by Dr Kevin Peters from Trent University suggests that sleep enhances our performance in complex motor learning tasks, as measured by an larger increase in accuracy levels obtained in playing guitar hero in the sleep condition compared to the wake condition.

However, an earlier paper by Cai & Rickard (2009) suggests that after controlling for circadian (time of day) and homeostatic (time since sleep) confounds, participants in the sleep conditions did not display any benefits in a motor sequence task.

The participants in their research were categorized into 3 conditions - a wake group, a 1 night sleep post-training group and a 2 night sleep post-training group. Participants were tasked to tap a number sequence, 4-1-3-2-4 repeatedly and reaction times (RTs) were measured. All participants trained at about 9.30am and were tested on 5.30pm on the day itself or on Day 2 and Day 3 depending on which conditions they were in.

Comparing difference scores of their RTs for the 3 different groups revealed no significant differences between them. If sleeping does indeed improve motor memory, we would expect a significant reduction in RTs for the sleep groups compared to the wake group. Therefore, it appears that after controlling for circadian and homeostatic factors, sleeping after training does not improve motor sequence performance.

Unfortunately, I do not have access to the exact methodology and results of Peter's study to verify if the concerns about the relevant confounds raised by Cai & Rickard (2009) are adequately addressed. Therefore, as far as I'm concerned, the jury is still out on the specific benefits (if any) conferred to motor memory by sleep. But I must say that Peter's design holds much promise (he certainly won't have any trouble finding willing and good subjects).

Well, regardless of whether sleeping helps you perfect that golf swing or ramp up your skill level on guitar hero, it’s still a good idea to get a good night's rest to ward off the negative effects associated with sleep deprivation in other domains of our lives. Afterall, according to a study by Falleti, Maruff, Collie, Darby & McStephen (2003), driving after being awake for 24hrs is like driving with a blood alcohol concentration of 0.05%. Not quite enough to get you arrested but probably more than enough to make you think twice about pulling that all-nighter.

Cai, D., & Rickard, T. (2009). Reconsidering the role of sleep for motor memory. Behavioral Neuroscience, 123 (6), 1153-1157 DOI: 10.1037/a0017672

Falleti MG, Maruff P, Collie A, Darby DG, & McStephen M (2003). Qualitative similarities in cognitive impairment associated with 24 h of sustained wakefulness and a blood alcohol concentration of 0.05%. Journal of sleep research, 12 (4), 265-74 PMID: 14633237

Is Money the Arbitrator of the Fine Line Between Self-Interest and Community Spirit?

2010-07-07T14:44:00.000-07:00

Does money serve as a great incentive and motivator or does it serve to undermine relationships? At the heart of the debate for society, this is akin to the perennial capitalism vis-à-vis communism conflict. And perhaps the truth is that they are both right.

Vohs, Mead & Goode's (2006) nine experimental studies, which culminated into an illuminating piece of work titled The Psychological Consequences of Money, found that both characteristics of money - a great incentive or an underminer of relationships - emerge from the same underlying process: money makes people feel self-sufficient and therefore behave accordingly.

In Experiment 1, participants were assigned randomly to three conditions. In two conditions, participants were reminded of money (Play Money and Money Prime) while in the control condition, participants were not reminded of money. In each condition, participants were instructed to unscramble jumbled up words to form sensible sentences, and therein lay the prime. In the Money Prime condition, the scrambled text contained concepts of money. In the Play Money and Control conditions, the scrambled texts were neutral, but participants in the Play Money condition were exposed to Monopoly money in their peripheral visual field.

Next, participants were given a challenging but solvable problem to work on. As the experimenter left the room, he offered that he was able to provide assistance if the participant wanted. How long the participants persisted before asking for help became the dependent variable to be measured.

It was observed that participants who were reminded of money (both Play Money and Money Prime) worked on the problem longer than control participants before requesting for help. The difference between the two money conditions (Play Money vs Money Prime) was insignificant.

Experiment 2 was a modification of Experiment 1 such that the constructs being measured were an abundance of money (High Money) against restricted amount of money (Low Money). Participants then had to read aloud an essay in front of a video camera. The video camera was used in place of an experimenter so as to remove the potential confound that might result from status differences between the experimenter and the student.

Participants in the High Money condition read about growing up with abundant financial resources, while participants in the Low Money condition read about growing up with meagre financial resources. Participants were then, like in Experiment 1, unknowingly tested on how long they would take to solve an unsolvable puzzle before requesting help.

Once more, participants in the High Money condition worked significantly longer than participants in the Low Money condition before asking for help. This experiment also confirmed that the effects of money did not depend on relative status differences between the participant and the experimenter/helper.

Given the findings thus far and the overall hypothesis, the authors predicted that people who value self-sufficiency would be less helpful than others because they will tend to expect others to be self-sufficient as well. The authors do not elaborate on this aspect, but a few reasons why this is a reasonable stipulation include:

the tendency for people to project their own personalities onto others in order to form more efficient judgments and anticipate behaviours of others,

the fact that schemas associated with ourselves are more accessible and thus more easily activated, and

the possibility that we have evolved psychological mechanisms to assume that when we are rich, the environment allows for it because we are in a resource-rich area, and we are more likely to be dealing with other rich people residing in our local environment.

Thus, in Experiments 3, 4 and 6 (all involving different sets of randomly selected subjects), the authors sought to test whether participants primed with money would be less helpful relative to control participants.

Using the word descrambling methodology from Experiment 1 to manipulate the priming for both money and neutral conditions, the DV - willingness to provide assistance - was then measured. Experiment 3 tested participants on their tendency to help out in a future task (willingness to help code the data sheets of the current experiment), while Experiment 4 tested their helpfulness on an immediate helping situation (willingness to help a fellow 'latecomer' participant, who was really a confederate, figure out the experiment's instructions). Experiment 6 assessed how willing participants were in donating their participation payment to a university student fund.

It was found that participants in the money condition volunteered to help code fewer data sheets (Experiment 3), spent half as much time providing help to the latecomer on the instructions (Experiment 4) and donated less money (Experiment 6) than participants in the control condition.

In Experiment 5, participants were made to play Monopoly with a confederate. After a few rounds, the game was cleared except for differing amounts of play money. Participants in the High Money condition were left with $4000 (participants will be aware that this is a large sum of Monopoly money having been sensitized to the game), while participants in the Low Money condition were left with $200. Control condition participants were left with no money. For High Money and Low Money participants, the money was kept in conscious sight for the second step of the experiment. At this step, High Money participants were asked to imagine a wealthy future while Low Money participants were asked to imagine a financially insecure future. Control participants were asked to imagine their plans for the next day.

This was followed by a staged accident where a new confederate, who was both blind to the condition the participants were in and carrying a lot of things, walks across the laboratory and drops his pencils (27 in total) in front of the participant. The number of pencils picked up by the participant became the measure of helpfulness.

Participants in the High Money condition helped gather significantly fewer pencils than participants in the Low Money and Control conditions. Helpfulness did not differ between the Low Money group and the Control group.

To ascertain self-sufficiency as the construct that is really being tested, the final three experiments tested the effects of money on social intimacy, desire to engage in leisure activities alone and preference to work alone.

In Experiment 7 involving screensavers, participants were randomly assigned to either the Money condition, Fish condition or No Screensaver condition. All participants were made to fill in questionnaires while sitting in front of an idle computer screen. After a few minutes, one of three screensaver types would appear - one depicting various denominations of currency floating underwater, one with fishes swimming underwater, and one with just a blank screen.

After some degree of exposure to the screensaver, participants were told they would get acquainted with another participant in the same experiment, but the experimenter would require some assistance to arrange the chairs for the session. Participants primed with the Money screensaver placed the two chairs for him or herself and the potential acquaintant farther apart compared to participants in both the Fish group and the No Screensaver group.

Participants primed with money appeared to place more social distance between themselves and others.

Experiment 8 tested whether money-primed participants would prefer being alone even when choosing leisure activities that are potentially of a social nature. The priming manipulation was similar to Experiment 7, except that instead of screensavers being used, participants were now facing posters. The Money condition participants faced a poster showing various denominations of currency, while the two control groups faced a poster showing either a seascape or a flower garden.

Participants were next given a nine-item questionnaire that asked them to choose between two leisure activities per question. Within each item, one option was an experience only one person could enjoy while the other option was for two or more people. Money-primed participants chose more individually-focused leisure activities than participants from the control groups.

Money primes thus appear to lead people to become less social.

Experiment 9 provided a more rigorous test of the self-sufficiency hypothesis by directly assessing social preferences. Participants were put through the screensaver primes from Experiment 7 before being asked whether they preferred to work alone or with others. Once more, participants desired to work less with a peer when exposed to money primes.

The nine experiments provide support for the proposed argument that money activates psychological mechanisms that bring about a state of self-sufficiency. It might even appear somewhat surprising that such minor tweaks in environmental and social conditions towards a heightened sensation of financial resources might induce a person to be more independent and socially insensitive.

As the authors sum up well, "The self-sufficient pattern helps explain why people view money as both the greatest good and evil. As countries and cultures developed, money may have allowed people to acquire goods and services that enabled the pursuit of cherished goals, which in turn diminished reliance on friends and family. In this way, money enhanced individualism but diminished communal motivations, an effect that is still apparent in people’s responses to money today."

So ultimately, perhaps whether you believe money is inherently good or evil might begin with what inclinations you have towards social dynamics and morals to begin with.

Vohs, K., Mead, N., & Goode, M. (2006). The Psychological Consequences of Money Science, 314 (5802), 1154-1156 DOI: 10.1126/science.1132491

Link between Sexual Motivation State and Dopamine Release in the mPOA?

2010-06-29T07:00:00.000-07:00

Is an increase in dopamine release in the medial preoptic area (mPOA) specifically related to male physical arousal and sexual behavior or does it have a bigger role in sexual motivation?

Kleitz-Nelson, Dominguez, Cornil & Ball (2010) investigated this question by using the Japanese quail (Coturnix japonica). The male quail does not an have an intromittent organ and therefore does not require an erection to successfully copulate. The researchers collected and measured the dopamine content from extracellular samples from the adult male quails’ mPOA every six minutes before, during and after exposure to a female quail.

What they found was that for male quails that copulated, their levels of extracellular dopamine increased dramatically past baseline levels (BL1-3) when the female quail was introduced (F1-F6) and decreased after the female quail was removed (POST1-POST6). Non-copulators did not exhibit an increase in extracellular dopamine levels.

In addition, for copulators, the researchers did not find any changes in extracellular dopamine levels between sampling periods during which the quails either engaged in the actual mating behavior or not. That is to say, during the sampling period, regardless of whether the male quail was engaging in coitus or not, their levels of extracellular dopamine levels showed increased levels as long as they are in the presence of the female.

The authors thus concluded that the rise in extracellular dopamine in the mPOA is not only involved in erection and ejaculation, as the copulators had high levels of extracellular dopamine regardless of whether they were actually engaging in mating behavior at that moment. And given that the quails do not require an erection for copulation to occur, the evidence suggests strongly that extracellular dopamine in the mPOA is specifically associated with sexual motivation and not just physical arousal.

Kleitz-Nelson, H., Dominguez, J., Cornil, C., & Ball, G. (2010). Is sexual motivational state linked to dopamine release in the medial preoptic area? Behavioral Neuroscience, 124 (2), 300-304 DOI: 10.1037/a0018767

"Can't Touch This" - The neurophysiology of pleasant touch

2010-06-19T02:26:00.000-07:00

Touch is crucially important for social communication, mediating how we perceive and interpret the actions of others. For example, waitresses who touch customers get better tips (Crusco & Wetzel, 1984). However, touch alone does not always lead to positive outcomes. For many years researchers have known that touch is moderated by factors such as type of touch, location of touch, situational context, and many others. Until recently however, they were uncertain as to how the social effect of touch was achieved. In this review by Olausson et al., the authors shed light on how pleasant and socially relevant aspects of touch are possibly mediated by a new distinct type of receptors called C-Tactile afferents.

To give a little background, human touch is generally considered to be mediated by 3 different type of receptors:

Thermal Receptors allow us to feel warmth and heat.
Mechanoreceptors allow us to feel pressure.
Nociceptors allow us to feel pain from chemical or heat damage.

For the most part, the mechanoreceptors are myelinated afferents. "Myelinated" means that the part of the neuron that transmits the signals are covered with an electrical insulator that allows it to conduct impulses at high speed (50m/s). Myelination is essential for quick reaction. "Afferent" neurons are neurons which carry information towards the central nervous system.

In the early part of the 20th century, mechanoreceptors that were unmyelinated were identified in various mammals like cats. They were termed C tactile (CT) afferents. For a time it was thought that humans did not share this primitive and slower tactile system, which conducted impulses at a speed of 1m/s. However in the 1990s they were soon found in abundance in hairy skin around the arms and legs, but not on the hairless surface of the palm.

The only appropriate time to use a lolcat.

Immediate testing of the sensitivity of these CT afferents found that they were for lack of a better word, wierd. They could not discriminate between pin pricks and smooth probe pressure, but however responded best to a slow stroking with a soft brush.

Direct evidence for the specific role of CT afferents was however, hard to achieve, because it was not possible to stimulate CT afferents without also activating myelinated afferents in normal subjects. The authors studied subjects who suffered from sensory neuronopathy, a condition where subjects lacked myelinated afferents but have intact C fibres. These subjects were long thought to have lost all tactile sensations but they detected soft brush stroking. Much of the CT effect was however, below conscious level. They could not effectively locate where the touch was delivered, and were not able to describe it, only saying that it was slightly to moderately pleasant.

FMRI imaging of the neuronopathy subjects also found that the posterior insula cortex was activated, but not traditional somatosensory systems identified with other tactile stimulation. This region is considered important for integrating converging information and passing it on to emotional systems. For one thing, it has been shown to be involved in the perception of pain.

Based on the evidence, the authors believe that CT system is involved in social touch. For one, the poor conduction velocity and poor discriminative properties of CT afferents make them ill-suited for processing the complex features of touch, features which are easily handled by other mechanoreceptors that are myelinated. Why then would they be present in humans? For another, the CT system appears to be tuned to slow, light touch, which occurs most often during close interactions with loved ones. The evidence from the sensory neuronopathy patients appears to confirm this fact.

So, what does this tell us? For the scientist, this research opens up new areas of research into the biological foundations of the social and emotional aspects of touch, which has longed focused purely on physical sensations. For the layman, not much. Intuitively we already reach out to stroke someone who is upset when we have no idea how to comfort that person, even if we do not know whether it would help. This review, and the research that has been done, confirms that physiologically, there is an effect. So, keep touching (as long as its appropriate, of course) :)

Ed's note: For another noteworthy study which was not mentioned in this review, but which I'm guessing was done by a postgraduate student of the author, you can refer to http://www.sciencedaily.com/releases/2009/04/090414084453.htm.

Olausson, H., Wessberg, J., Morrison, I., McGlone, F., & Vallbo, �. (2010). The neurophysiology of unmyelinated tactile afferents Neuroscience & Biobehavioral Reviews, 34 (2), 185-191 DOI: 10.1016/j.neubiorev.2008.09.011

Is your best friend’s relationship advice/decision really the best for you?

2010-06-16T08:17:00.000-07:00

When you have a relationship decision to make and you are at a loss as to which is your best available option, are your friends the ones you turn to? If your answer is yes, the following article may make you think twice in the future.

In the article Risk-Taking in Relationships: Difference in deciding for Oneself Versus for a Friend, the authors explored the idea that people tend to make riskier decisions or give riskier advice for their friends as opposed to when they are making one for themselves. Most existing research has so far focused on people making decisions for themselves. However, there is a lack of empirical research on decision making for others, which is a rather common situation in life. Examples include doctors making decisions for patients or politicians for their constituents. The authors decided that decision making in relationships would be a good starting point as participants are undergraduates, often with a good chance of encountering such relationship choices.

The first experiment asked 201 participants to fill in a questionnaire of 11 scenarios concerning real-life relationship problems. There were two options for each scenario, one that was risk-averse (e.g. a fun time with friends) and another that was risk-taking (e.g. potentially having a fun time with an attractive member of the opposite sex). All participants were grouped into 3 categories: (1) deciding for themselves, (2) deciding for a same-sex friend, and (3) advising a same sex friend. A risk-averse option receives a score of 0 and the alternative gets a score of 1. Therefore, if a participant chose the risk-taking option for all 11 situations, the score would be 11.

The results indicated that participants made riskier choices for their friends as opposed to for themselves. Moreover, results showed that there were no differences for the other-decision group and the other-advice group. However, a life impact analysis of the scenarios reveals that the impact of the situation on the person’s future life could influence the self-other difference. Therefore the second experiment was conducted to investigate this possibility.

In the second experiment, 20 scenarios were pre-rated with 12 chosen. Six of them were of the highest score for low life-impact and vice versa for the high impact scenarios. In general, the results concurred with the first experiment and the possibility of self-other difference from low or high impact scenarios was also confirmed. Participants were more risk-taking in low impact scenarios and more risk-averse in high impact scenarios. However, a non-linear analysis suggested that the conclusion might not be as straightforward. Evidence from the non-linear analysis indicated that not every low-impact scenario had participants choosing a more risk-taking decision for their friend. Self-other difference was non-existent or reversed in three of the six low-impact scenarios. For example, when asked if they would give their phone number to someone they just met at a party, 80% said they would but only 67% said they would tell their friend to do the same thing. Experiment 3 sought to find out why people take more risk in some scenarios when it comes to deciding for a friend while other scenarios produce a completely different set of results.

Before discussing Experiment 3 proper, a brief review of some literature to provide rational explanations will prove useful. People in general take into account more information when deciding for oneself than for others. One way to interpret this is that positive consequences are accounted for in oneself and others but people will also focus on the negative consequences only when deciding for themselves. The corollary is that there is a bias towards riskier decisions for one's friend since positive consequences weigh more in the decision-making process. Insofar as this explanation is true, we can reasonably expect self-other differences to disappear for high-impact scenarios, but what about the three low impact ones previously mentioned?

Each scenario (giving out a phone number, going to an out-of-town concert and buying a gold chain for a significant other) has the potential to produce negative outcomes. For example, going out of town for a concert may be dangerous if you find yourself too far from home with a person you've just met. As a consequence, there might be a chance that such considerations are not completely ignored despite the scenario being generally of a low impact.

There are generally two mechanisms by which negative information can be directed when making decisions. The first states that such information is not even brought to mind when deciding for others. If this is the case, explicitly stating the negative consequence would serve to negate the self-other difference. The second possibility is that the consequences, albeit being brought to mind, are given less weight.

Experiment 3 tested both versions. For this experiment, each scenario was provided with both positive and negative consequences for each risk option (same questionnaire as Experiment 2) for one group and no such consequential information for another group. If this inclusion eliminates the self-other difference, the first mechanism is supported. In addition, the conclusion of this experiment asked participants to provide reasons for their choices in the three low-impact scenarios with the largest self-other differences as in Experiment 2. If participants stated more negative reasons, it would mean they were aware but chose to ignore the consequences.

Results of Experiment 3 indicated that, regardless whether consequential information is present, the self-other difference is not removed for the low-impact scenarios. For the open-ended questions at the end, participants gave more negative reasons when deciding for themselves than for others. This raises an interesting question because it contradicts the prospect theory where people in general place more importance on losses than on gains. Maybe we place a different emphasis on our decisions when it comes to deciding for others.

With these results in mind, we definitely do know that people take more risks for their friends in decisions, at least with respect to relationships. So, before the next time you go banging on your friend’s door regarding your relationship problems, do bear in mind what their decision could mean to you.

Beisswanger, A., Stone, E., Hupp, J., & Allgaier, L. (2003). Risk Taking in Relationships: Differences in Deciding for Oneself Versus for a Friend Basic and Applied Social Psychology, 25 (2), 121-135 DOI: 10.1207/S15324834BASP2502_3

Sorry honey, I just had to buy that dress! - When cognitive overload undermines our self-regulatory ability.

2010-06-14T00:40:00.000-07:00

Counterintuitively, people who exercise self control in some way, such as dieting or trying not to look at or think about something, might end up buying things more impulsively instead if given the opportunity.

Vohs & Faber (2007) explain in their study, Spent Resources: Self-Regulatory Resource Availability Affects Impulse Buying, that opportunities for impulse purchasing have increased with the proliferation of ATMs, shopping on the Internet, and shop-at-home television programs. Depletion of cognitive self-regulatory resources coupled with ever-increasing avenues for impulse buying might just be the answer.

In one experiment, 35 undergraduate participants were made to watch a video of a woman talking on the pretext that they were going to judge her personality later. To suppress one group's attentional resources, irrelevant words were flashed at the bottom of the screen and participants were told to ignore the irrelevant words and focus instead on the woman. Another group was given no such instruction to divert their attention away from the words, and thus served as the control group. After the video, participants were told that they were taking part in a marketing study to determine the prices that students would pay for various products.

It was found that participants who had their attention manipulated assigned significantly higher prices to the products than participants in the control group.

In the second experiment, 73 undergraduates participated by first completing the trait Buying Impulsiveness Scale (BIS), a scale developed by Rook and Fisher (1995) which measures generalized urges to spend impulsively. This was followed by a thought suppression exercise where participants were induced with the thought of a 'white bear', an interesting experimental technique developed by Wegner in 1989 that has been proven to drain considerable cognitive resources. Participants were told to write down their thoughts for the next few minutes. Participants in the Thought Suppression condition were told that they should try and avoid thinking of a white bear and if they did think of a white bear, they should place a check mark on their paper and then resume recording their thoughts. Participants in the No Suppression condition could think of anything they wanted, including white bears.

After this, participants were told that they were going to be involved in a study about introducing new products at the university bookstore. Participants would be given $10 for their participation in the study, after which they could either leave with the money, or they could make a purchase with the items that were available as part of the bookstore's product study.

It was found that spontaneous buying behaviour is once more predicted by mental resource depletion, as students who did not have to suppress their thoughts were more likely to keep the $10 and leave. Additionally, an interaction effect between dispositional buying impulsiveness (as determined by the BIS) and the self-regulatory resource condition was found. As the authors assert, "Among people who are prone to buying impulsively, temporary lapses in self-control ability signal a strong possibility that impulsive, unplanned, and perhaps unwanted spending may occur."

In the last experiment of the study, 40 undergraduate subjects took a variant of the second experiment to determine that the results were not confounded by other cognitive or affective traits, such as the desirability of the items being purchased.

This study extends the research on impulse buying, which has come a long way since the 1980s where people were simply labeled as either impulsive or nonimpulsive purchasers, effectively indicating that there is an interaction between both dispositional and environmental influences that determines impulse-buying. In other words, personality and social factors both play a part. The authors conclude: "Self-regulatory resource availability would be an important element in determining when and why people engage in impulsive spending." Without enough self-regulatory resources, people will be less able to overcome urges and substitute desirable behaviours with undesired ones. Thus, temporary reductions in the capacity to self-regulate leads to stronger impulsive buying tendencies.

From this research, it appears that people in modern contexts do not stand confidently in the ability to control their temptations, as contemporary city-living inundates our senses with a twin barrage of cognitive overload as well as opportunities to spend.

Vohs, K., & Faber, R. (2007). Spent Resources: Self‐Regulatory Resource Availability Affects Impulse Buying Journal of Consumer Research, 33 (4), 537-547 DOI: 10.1086/510228

Sorry, what's your name again? - How stress impairs our social memory.

2010-06-04T02:00:00.000-07:00

Ever felt that someone hasn't been paying attention to what you were saying in previous conversations because he/she forgets biographic information about you that you had mentioned countless times? Well, it turns out that it might just be that they're stressed out by something else.

In their paper, Stress Impairs Retrieval of Socially Relevant Information, Merz, Wolf & Hennig (2010) investigated the hypothesis that parts of our social memory (memory about names, birth dates, parts of other people’s life) fail because of stress.

15 women and 14 men were recruited to take part in an experiment whereby they were randomized into either the Stress or Control conditions. All participants started the experiment by memorizing two biographical notes (one from each gender) which includes photos, home towns and parts of their life stories.

Stress was then induced on the participants in the stress condition by instructing them that they would have to give a public speech 10 minutes later. Cortisol levels in saliva samples collected during 5 different time intervals during the whole experiment were used to quantify their stress levels.

All participants were then tested on the biographical notes that they learnt at the beginning of the experiment. Participants were tested on recognition (selecting the correct answer out of 5 choices), correction (marking the incorrect answer out of 5 choices) and reproduction (answering semi-open ended questions). Global Memory indicates the average of the three tests.

The authors found that participants in the stress condition had significantly lower recognition, reproduction and global memory scores than participants in the control condition.

Mean cortisol response during memory retrieval of responders (participants who show stress induced cortisol increase) also had a significant negative correlation with the recognition task and global memory score.

The authors conclude that acute stress reduces our ability to retrieve socially relevant information and that there was an association between these stress-induced retrieval deficiencies and cortisol response to the stressor.

So, cut that person some slack when he/she forgets something about you; it might just be the cortisol, or even the pressure you're inducing on the person to remember stuff about you!

Merz, C., Wolf, O., & Hennig, J. (2010). Stress impairs retrieval of socially relevant information. Behavioral Neuroscience, 124 (2), 288-293 DOI: 10.1037/a0018942

Psychothalamusing

2010-05-28T02:29:00.000-07:00

The name Psychothalamus was conceived from the combination of the words "Psychology" and "Hypothalamus" and is managed by a passionate team of psychology enthusiasts from the National University of Singapore and Singapore Management University.

Although the blog will focus mainly on cognitive neuroscience articles, expect a variety of exciting psychology topics ranging from human performance, social psychology, evolutionary psychology and even game theory as and when we come across studies and ideas that pique our interest and - we're confident on this - will pique yours too.

'Nuff said, because we believe in cutting to the chase. Have fun Psychothalamusing!

Cheers,
The Authors