Basic Instinct

Kevin Lewis

December 01, 2009

Disrupting the prefrontal cortex diminishes the human ability to build a good reputation

Daria Knoch, Frédéric Schneider, Daniel Schunk, Martin Hohmann & Ernst Fehr
Proceedings of the National Academy of Sciences, forthcoming

Reputation formation pervades human social life. In fact, many people go to great lengths to acquire a good reputation, even though building a good reputation is costly in many cases. Little is known about the neural underpinnings of this important social mechanism, however. In the present study, we show that disruption of the right, but not the left, lateral prefrontal cortex (PFC) with low-frequency repetitive transcranial magnetic stimulation (rTMS) diminishes subjects' ability to build a favorable reputation. This effect occurs even though subjects' ability to behave altruistically in the absence of reputation incentives remains intact, and even though they are still able to recognize both the fairness standards necessary for acquiring and the future benefits of a good reputation. Thus, subjects with a disrupted right lateral PFC no longer seem to be able to resist the temptation to defect, even though they know that this has detrimental effects on their future reputation. This suggests an important dissociation between the knowledge about one's own best interests and the ability to act accordingly in social contexts. These results link findings on the neural underpinnings of self-control and temptation with the study of human social behavior, and they may help explain why reputation formation remains less prominent in most other species with less developed prefrontal cortices.


Hungry People Prefer More Mature Mates: A Field Test of the Environmental Security Hypothesis

Terry Pettijohn, Donald Sacco & Melissa Yerkes
Journal of Social, Evolutionary, and Cultural Psychology, September 2009, Pages 216-232

The current studies tested the prediction that the visceral experience of hunger would lead men and women to show sex-specific preferences for mature partners because of the perceived value of mature characteristics under conditions of resource scarcity. Across two studies, unique samples of college students (N=328) were asked their preferences about ideal mates before or after eating dinner at a dining hall. Consistent with predictions, hungry males preferred females with more physically mature features, specifically females who were relatively heavier, taller, and older. Female participants who were hungry showed a marginally elevated preference for partners with a more mature personality profile. Hunger salience, manipulated by varying when hunger was assessed, had little effect on the overall pattern of results. Collectively, these studies indicate that visceral states can influence perceptions of environmental security, resulting in a preference shift for partners with characteristics that imply elevated maturity.


Eye-Tracking of Men's Preferences for Waist-to-Hip Ratio and Breast Size of Women

Barnaby Dixson, Gina Grimshaw, Wayne Linklater & Alan Dixson
Archives of Sexual Behavior, forthcoming

Studies of human physical traits and mate preferences often use questionnaires asking participants to rate the attractiveness of images. Female waist-to-hip ratio (WHR), breast size, and facial appearance have all been implicated in assessments by men of female attractiveness. However, very little is known about how men make fine-grained visual assessments of such images. We used eye-tracking techniques to measure the numbers of visual fixations, dwell times, and initial fixations made by men who viewed front-posed photographs of the same woman, computer-morphed so as to differ in her WHR (0.7 or 0.9) and breast size (small, medium, or large). Men also rated these images for attractiveness. Results showed that the initial visual fixation (occurring within 200 ms from the start of each 5 s test) involved either the breasts or the waist. Both these body areas received more first fixations than the face or the lower body (pubic area and legs). Men looked more often and for longer at the breasts, irrespective of the WHR of the images. However, men rated images with an hourglass shape and a slim waist (0.7 WHR) as most attractive, irrespective of breast size. These results provide quantitative data on eye movements that occur during male judgments of the attractiveness of female images, and indicate that assessments of the female hourglass figure probably occur very rapidly.


Compassionate Values and Presidential Politics: Mortality Salience, Compassionate Values, and Support for Barack Obama and John McCain in the 2008 Presidential Election

Kenneth Vail, Jamie Arndt, Matt Motyl & Tom Pyszczynski
Analyses of Social Issues and Public Policy, December 2009, Pages 255-268

In line with terror management theory, this research demonstrates that mortality salience motivated increased support for John McCain in the absence of reminders of compassionate values. However, polls had indicated that Barack Obama was generally perceived as the more compassionate of the two candidates. Thus, when compassionate values were made salient, death reminders motivated participants to uphold these values by significantly increasing their support for the more compassionate Barack Obama instead. The implications of these findings for terror management theory, the 2008 presidential election, and political endorsements are discussed.


Individual differences in psychoticism predict attention for emotional faces

Vladimir Miskovic & Louis Schmidt
Personality and Individual Differences, forthcoming

Psychoticism is a personality trait characterized by disregard for social conventions, coldness, and lack of empathy. We examined whether individual differences in psychoticism predicted attention biases to pictures of happy and angry faces presumed to elicit social approach and social withdrawal behaviors, respectively. Our analyses revealed that high levels of psychoticism were related to reduced attentional capture by angry faces. There were also within-group attention bias differences such that individuals low in psychoticism exhibited cognitive vigilance for both happy and angry faces relative to neutral, while those high in psychoticism did not show preferential processing of emotional expressions. These findings suggest that individual differences in psychoticism are related to alterations in the cognitive processing of socially relevant signals.


Intranasal Oxytocin Improves Emotion Recognition for Youth with Autism Spectrum Disorders

Adam Guastella, Stewart Einfeld, Kylie Gray, Nicole Rinehart, Bruce Tonge, Timothy Lambert & Ian Hickie
Biological Psychiatry, forthcoming

Background: A diagnostic hallmark of autism spectrum disorders is a qualitative impairment in social communication and interaction. Deficits in the ability to recognize the emotions of others are believed to contribute to this. There is currently no effective treatment for these problems.

Methods: In a double-blind, randomized, placebo-controlled, crossover design, we administered oxytocin nasal spray (18 or 24 IU) or a placebo to 16 male youth aged 12 to 19 who were diagnosed with Autistic or Asperger's Disorder. Participants then completed the Reading the Mind in the Eyes Task, a widely used and reliable test of emotion recognition.

Results: In comparison with placebo, oxytocin administration improved performance on the Reading the Mind in the Eyes Task. This effect was also shown when analysis was restricted to the younger participants aged 12 to 15 who received the lower dose.

Conclusions: This study provides the first evidence that oxytocin nasal spray improves emotion recognition in young people diagnosed with autism spectrum disorders. Findings suggest the potential of earlier intervention and further evaluation of oxytocin nasal spray as a treatment to improve social communication and interaction in young people with autism spectrum disorders.


Cognition Without Control: When a Little Frontal Lobe Goes a Long Way

Sharon Thompson-Schill, Michael Ramscar & Evangelia Chrysikou
Current Directions in Psychological Science, October 2009, Pages 259-263

The prefrontal cortex is crucial for the ability to regulate thought and control behavior. The development of the human cerebral cortex is characterized by an extended period of maturation during which young children exhibit marked deficits in cognitive control. We contend that prolonged prefrontal immaturity is, on balance, advantageous and that the positive consequences of this developmental trajectory outweigh the negative. Particularly, we argue that cognitive control impedes convention learning and that delayed prefrontal maturation is a necessary adaptation for human learning of social and linguistic conventions. We conclude with a discussion of recent observations that are relevant to this claim of evolutionary trade-offs in a wide range of research areas, including attention-deficit hyperactivity disorder, autism spectrum disorders, creativity, and sleep.


Real Estate Prices: Seasonality's Sentiment Effect

Guy Kaplanski & Haim Levy
Bar Ilan University Working Paper, June 2009

Prices of real estate, in real terms, reveal a significant seasonality, where the highest rates of return are obtained in the spring and early summer and the lowest rates of return are obtained in the fall. The main factors that explain the seasonality in prices are the monthly change in the number of daylight hours and the latitude of the relevant area under consideration. Confronting the results with the two common explanations for seasonality in the literature, the Matching Theory (MT) and the Bargaining Power (BP) Hypothesis, the results are better explained by the Seasonal Affective Disorder (SAD) which has been found in other studies to affect people's health, their risk attitude, and consequently their investment decisions which, in turn, affect assets prices.


The Restraint Bias: How the Illusion of Self-Restraint Promotes Impulsive Behavior

Loran Nordgren, Frenk van Harreveld & Joop van der Pligt
Psychological Science, December 2009, Pages 1523-1528

Four studies examined how impulse-control beliefs - beliefs regarding one's ability to regulate visceral impulses, such as hunger, drug craving, and sexual arousal - influence the self-control process. The findings provide evidence for a restraint bias: a tendency for people to overestimate their capacity for impulse control. This biased perception of restraint had important consequences for people's self-control strategies. Inflated impulse-control beliefs led people to overexpose themselves to temptation, thereby promoting impulsive behavior. In Study 4, for example, the impulse-control beliefs of recovering smokers predicted their exposure to situations in which they would be tempted to smoke. Recovering smokers with more inflated impulse-control beliefs exposed themselves to more temptation, which led to higher rates of relapse 4 months later. The restraint bias offers unique insight into how erroneous beliefs about self-restraint promote impulsive behavior.


Cortisol administration acutely reduces threat-selective spatial attention in healthy young men

Peter Putman, Erno Hermans & Jack van Honk
Physiology & Behavior, forthcoming

There is mounting evidence that single administrations of glucocorticoids may acutely reduce human fear. We previously reported that administration of cortisol acutely reduced non-spatial selective attention to fearful faces and likewise reduced preferential processing of fearful faces in a spatial working memory task. Here we report the acute effects of 40 mg cortisol (administered in a double-blind, placebo-controlled crossover design) on a different experimental task for measuring threat-selective attention. Twenty healthy young males had to localize a target which was presented in a peripheral location that was either gazed at or not by a preceding dynamic happy or fearful face. This reliable method has been used repeatedly to demonstrate fear-driven selective attention. Present results showed that after placebo, as usual, the fearful gaze cues caused stronger orienting of attention than happy faces. Cortisol abolished this typical anxious response pattern, but only in low anxious participants. These data provide evidence that cortisol acutely influences also spatial threat-selective attention. Possible neuroendocrine mechanisms are discussed.


Trustworthy? The Brain Knows: Implicit Neural Responses to Faces that Vary in Dark Triad Personality Characteristics and Trustworthiness

David Gordon & Steven Platek
Journal of Social, Evolutionary, and Cultural Psychology, September 2009, Pages 182-200

Deciding whether to trust another individual is one of the most important decisions a person has to make, especially in social contexts. The ability to make accurate judgements of trustworthiness is predicted to be evolutionarily advantageous. There is evidence for a consistent consensus when rating faces on trustworthiness, and faces rated as both untrustworthy and trustworthy have been shown to activate the amygdala. We investigated the extent to which amygdala activation corresponds to measured trustworthiness associated with facial stimuli. Using functional magnetic resonance imaging (fMRI) we scanned 6 participants while they viewed faces of people that varied on The Dark Triad personality characteristics. There was significant activation in the amygdala in response to faces associated with high psychopathy, high Machiavellianism and high trusting behaviour. The findings support recent work demonstrating the relationship between facial morphometric geometry and personality traits. The psychopathy findings in particular supports recent work suggesting threat to be a large component of implicit trustworthiness decisions and also suggests the neural substrates associated with cheater detection are attuned to facial geometry that might represent psychopathy.


'Unwilling' versus 'unable': capuchin monkeys' (Cebus apella) understanding of human intentional action

Webb Phillips, Jennifer Barnes, Neha Mahajan, Mariko Yamaguchi & Laurie Santos
Developmental Science, November 2009, Pages 938-945

A sensitivity to the intentions behind human action is a crucial developmental achievement in infants. Is this intention reading ability a unique and relatively recent product of human evolution and culture, or does this capacity instead have roots in our non-human primate ancestors? Recent work by Call and colleagues (2004) lends credence to the latter hypothesis, providing evidence that chimpanzees are also sensitive to human intentions. Specifically, chimpanzees remained in a testing area longer and exhibited fewer frustration behaviors when an experimenter behaved as if he intended to give food but was unable to do so, than when the experimenter behaved as if he had no intention of giving food. The present research builds on and extends this paradigm, providing some of the first evidence of intention reading in a more distant primate relative, the capuchin monkey (Cebus apella). Like chimpanzees, capuchin monkeys distinguish between different goal-directed acts, vacating an enclosure sooner when an experimenter acts unwilling to give food than when she acts unable to give food. Additionally, we found that this pattern is specific to animate action, and does not obtain when the same actions are performed by inanimate rods instead of human hands (for a similar logic, see Woodward, 1998). Taken together with the previous evidence, the present research suggests that our own intention reading is not a wholly unique aspect of the human species, but rather is shared broadly across the primate order.


The Face of Need: Facial Emotion Expression on Charity Advertisements

Deborah Small & Nicole Verrochi
Journal of Marketing Research, December 2009, Pages 777-787

Advertisements for charities often display photographs of the people they help to evoke the kind of sympathy that engenders giving. This article examines how the expression of emotion on a victim's face affects both sympathy and giving. Building on theories of emotional contagion and sympathy, the authors propose that (1) people "catch" the emotions displayed on a victim's face and (2) they are particularly sympathetic and likely to donate when they see sad expressions versus happy or neutral expressions. Consistent with emotional contagion, participants felt sadder when viewing a sad-faced victim, and their own sadness mediated the effect of emotion expression on sympathy. Contagion effects are automatic and noninferential, but they are diminished by deliberative thought. The authors discuss the implications of using subtle emotional expressions on charitable and other marketing appeals.


Autonomic reactions to mutilation pictures: Positive affect facilitates safety signal processing

Laura Oliveira, Leticia Oliveira, Mateus Joffily, Pedro Pereira-Junior, Peter Lang, Mirtes Pereira, Ivan Figueira & Eliane Volchan
Psychophysiology, July 2009, Pages 870-873

For survival, humans are continuously vigilant for signs of danger. Equally important, but less studied, is our ability to detect and respond to safety cues. The trait of positive affect may be a key component determining human variability in safety detection. Here we investigate autonomic and self-report reactivity to pictures of mutilated bodies, after reading a text about the art of mimicking injuries in the movies. Participants that scored high in positive affect trait showed attenuated autonomic reactions to the mutilation pictures. Thus, high positive affect facilitated engagement in safety cues and modulated reflexive reactions of the brain's defense system.

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