Outperforming the Group

Kevin Lewis

May 12, 2010

Adaptive specializations, social exchange, and the evolution of human intelligence

Leda Cosmides, Clark Barrett & John Tooby
Proceedings of the National Academy of Sciences, forthcoming

Blank-slate theories of human intelligence propose that reasoning is carried out by general-purpose operations applied uniformly across contents. An evolutionary approach implies a radically different model of human intelligence. The task demands of different adaptive problems select for functionally specialized problem-solving strategies, unleashing massive increases in problem-solving power for ancestrally recurrent adaptive problems. Because exchange can evolve only if cooperators can detect cheaters, we hypothesized that the human mind would be equipped with a neurocognitive system specialized for reasoning about social exchange. Whereas humans perform poorly when asked to detect violations of most conditional rules, we predicted and found a dramatic spike in performance when the rule specifies an exchange and violations correspond to cheating. According to critics, people's uncanny accuracy at detecting violations of social exchange rules does not reflect a cheater detection mechanism, but extends instead to all rules regulating when actions are permitted (deontic conditionals). Here we report experimental tests that falsify these theories by demonstrating that deontic rules as a class do not elicit the search for violations. We show that the cheater detection system functions with pinpoint accuracy, searching for violations of social exchange rules only when these are likely to reveal the presence of someone who intends to cheat. It does not search for violations of social exchange rules when these are accidental, when they do not benefit the violator, or when the situation would make cheating difficult.


Humans show mate copying after observing real mate choices

Skyler Place, Peter Todd, Lars Penke & Jens Asendorpf
Evolution and Human Behavior, forthcoming

When searching for a mate, one must gather information to determine the mate value of potential partners. By focusing on individuals who have been previously chosen by others, one's selection of mates can be influenced by another's successful search-a phenomenon known as mate copying. We show mate copying in humans with a novel methodology that closely mimics behavioral studies with non-human animals. After observing instances of real mating interest in video recordings of speed-dates, both male and female participants show mate copying effects of heightened short-term and long-term relationship interest towards individuals in dates they perceived as successful. Furthermore, the relative attractiveness of observers and observed plays a mediating role in whom an individual will choose to copy.


Testosterone Fluctuations in Young Men: The Difference Between Interacting With Like and Not-Like Others

Catherine DeSoto, Robert Hitlan, Rory-Sean Deol & Derrick McAdams
Evolutionary Psychology, April 2010, Pages 173-188

The current study investigated young men's testosterone level changes as a result of interacting with other men. Male participants (n = 84) were led to believe that a group they would be interacting with was either similar to them or not similar. The interaction was then one of two types: the other group members were inclusive, or the others excluded the participant during the group interaction. Participants provided saliva samples before and after the interaction. Results suggest that interacting with highly similar men increases circulating testosterone whereas interacting with highly dissimilar men actually lowers testosterone. The nature of the interaction was less important than similarity. Considering that testosterone surges may relate to attempts to gain status within one's group, the results are interpreted as consistent with viewing hormonal changes as a mechanism to alter current behavioral propensities in ways that are likely to be most adaptive. Exploratory analyses suggest a methodologically interesting suppressor effect of the self-report items in predicting testosterone changes.


Am I Doing Better Than You? That Depends On Whether You Ask Me in English or Chinese: Self-Enhancement Effects of Language As A Cultural Mindset Prime

Spike Lee, Daphna Oyserman & Michael Harris Bond
Journal of Experimental Social Psychology, forthcoming

Westerners tend to judge themselves positively unless their failure relative to others is obvious, in which case they tend to distance themselves from outperforming others. Whether this tendency to self-enhance in social-comparison situations is universal or culture-bound is hotly debated. Rather than construe self-enhancement as either universal or culture-bound, we propose that its effects depend on the cultural mindset that is salient at the moment of self-reflection. A cultural mindset is a mental representation containing culture-congruent content, procedures, and goals. We focused on individual and collective mindsets, using language as an unobtrusive mindset prime and predicting that people would be more self-enhancing when an individual mindset was made salient by using English than when a collective mindset was made salient by using Chinese. Three studies supported this hypothesis. Chinese students self-enhanced (rating themselves as better than others and distancing themselves from outperforming others) more when primed with an individual mindset.


Peer Effects in Team Sports: Empirical Evidence From NCAA Relay Teams

Craig Depken & Lisa Haglund
Journal of Sports Economics, forthcoming

This article investigates whether peer effects manifest in the performance of National Collegiate Athletic Association (NCAA) 4 x 400 m men's relay teams. We test whether increasing the average quality of team members has a nonlinear and ultimately deleterious impact on team performance, measured by, relay time. Using both absolute and relative performance measures we find that increasing average team member quality improves team performance but at a decreasing rate. The authors attribute these diminishing returns to negative peer effects after finding that relay teams comprised of higher quality runners are more likely to underperform relative to their predicted quality.


Social-comparative feedback affects motor skill learning

Rebecca Lewthwaite & Gabriele Wulf
Quarterly Journal of Experimental Psychology, April 2010, Pages 738-749

This study examined motivational effects of feedback on motor learning. Specifically, we investigated the influence of social-comparative feedback on the learning of a balance task (stabilometer). In addition to veridical feedback (error scores reflecting deviation from the target horizontal platform position) about their own performance after each trial, two groups received false normative information about the "average" score of others on that trial. Average performance scores indicated that the participant's performance was either above (better group) or below (worse group) the average, respectively. A control group received veridical feedback about trial performance without normative feedback. Learning as a function of social-comparative feedback was determined in a retention test without feedback, performed on a third day following two days of practice. Normative feedback affected the learning of the balance task: The better group demonstrated more effective balance performance than both the worse and control groups on the retention test. Furthermore, high-frequency/low-amplitude balance adjustments, indicative of more automatic control of movement, were greater in the better than in the worse group. The control group exhibited more limited learning and less automaticity than both the better and the worse groups. The findings indicate that positive normative feedback had a facilitatory effect on motor learning.


Mere Categorization and the Frog‐Pond Effect

Mark Alicke, Ethan Zell & Dorian Bloom
Psychological Science, February 2010, Pages 174-177

Zell and Alicke (2009) have shown that comparisons with a few people have a stronger influence on self‐evaluations than comparisons with larger samples. One explanation for this effect is that people readily categorize their standing in small groups as "good" or "bad," which supersedes large‐sample data. To test this explanation, we created a situation in which students learned that their performance ranked 5th or 6th out of 10 persons on a task. In each experimental session, two groups, each containing 5 people, were created by random assignment. Some students learned that their performance placed them last in one group of 5, and some learned that they were first in the other group of 5. In the other conditions, participants learned only that that they were 5th or 6th in the group of 10. Results showed that being last in the superior group led to lower self‐ evaluations than being first in the inferior group.


When They're Sixty-Four: Peer Effects and the Timing of Retirement

Kristine Brown & Ron Laschever
University of Illinois Working Paper, December 2009

This paper examines the effect of peers on an individual's likelihood of retirement using data from the Los Angeles Unified School District. We show that two large pension reforms differentially impacted the financial incentives for retirement within and across schools. Using an administrative dataset of the full population of district teachers ages 55 and over, covering the years 1997-2001 (n=31,931), we construct school-level peer groups and calculate the impact of the reforms on pension financial incentives. We use a measure of the unexpected (reform-induced) change in the pension wealth of teachers in a school as an instrument for retirements at that school. After controlling for individual and school characteristics, and including individual fixed effects, our IV estimates of the effect of colleagues' retirement on a teacher's own likelihood of retirement are sizable and statistically significant. For example, we find that the retirement of an additional teacher in the previous year at the same school increases a teacher's own likelihood of retirement by an additional 1.8 percentage points.


Why Copy Others? Insights from the Social Learning Strategies Tournament

L. Rendell, R. Boyd, D. Cownden, M. Enquist, K. Eriksson, M. Feldman, L. Fogarty, S. Ghirlanda, T. Lillicrap & K. Laland
Science, 9 April 2010, Pages 208-213

Social learning (learning through observation or interaction with other individuals) is widespread in nature and is central to the remarkable success of humanity, yet it remains unclear why copying is profitable and how to copy most effectively. To address these questions, we organized a computer tournament in which entrants submitted strategies specifying how to use social learning and its asocial alternative (for example, trial-and-error learning) to acquire adaptive behavior in a complex environment. Most current theory predicts the emergence of mixed strategies that rely on some combination of the two types of learning. In the tournament, however, strategies that relied heavily on social learning were found to be remarkably successful, even when asocial information was no more costly than social information. Social learning proved advantageous because individuals frequently demonstrated the highest-payoff behavior in their repertoire, inadvertently filtering information for copiers. The winning strategy (discountmachine) relied nearly exclusively on social learning and weighted information according to the time since acquisition.


Mechanisms underlying responses to inequitable outcomes in chimpanzees, Pan troglodytes

Sarah Brosnan, Catherine Talbot, Megan Ahlgren, Susan Lambeth & Steven Schapiro
Animal Behaviour, forthcoming

Several species of nonhuman primates respond negatively to inequitable outcomes, a trait shared with humans. Despite previous research, questions regarding the response to inequity remain. In this study, we replicated the methodology from previous studies to address four questions related to inequity. First, we explored the impact of basic social factors. Second, we addressed whether negative responses to inequity require a task, or exist when rewards are given for ‘free'. Third, we addressed whether differences in the experimental procedure or the level of effort required to obtain a reward affected responses. Finally, we explored the interaction between ‘individual' expectations (based on one's own previous experience) and ‘social' expectations (based on the partner's experience). These questions were investigated in 16 socially housed adult chimpanzees using eight conditions that varied across the dimensions of reward, effort and procedure. Subjects did respond to inequity, but only in the context of a task. Differences in procedure and level of effort required did not cause individuals to change their behaviour. Males were more sensitive to social than to individual expectation, while females were more sensitive to individual expectation. Finally, subjects also increased refusals when they received a better reward than their partner, which has not been documented previously. These results indicate that chimpanzees are more sensitive to reward inequity than procedures, and that there is interaction between social and individual expectations that depends upon social factors.


Compared to whom? Subjective social status, self-rated health, and referent group sensitivity in a diverse U.S. sample

Lisa Wolff, S V Subramanian, Dolores Acevedo-Garcia, Deanne Weber & Ichiro Kawachi
Social Science & Medicine, June 2010, Pages 2019-2028

Emerging research has revealed that subjective social status (SSS), or how people perceive their position in the social hierarchy, is significantly associated with multiple health outcomes. Yet few studies have examined how this association is affected by the person or group to whom respondents are comparing themselves. While previous studies have used distal referent groups when assessing SSS, scholars have suggested that individuals may prefer to make comparisons to those who share similar characteristics to themselves. Overall, there has been little empirical analysis assessing the health impact of comparing oneself to one referent group over another. Using a diverse, national U.S. sample (n=3,644), this study explores whether the relationship between SSS and self-rated health is sensitive to the referent used for social comparison. Data are from respondents who completed the ConsumerStyles and HealthStyles mail surveys and who have assessed their SSS against four referents: others in American society, others of the same race or ethnicity, neighbors, and parents at the same age. Self-rated health was the dependent variable, while we controlled for household income, education, home ownership, race/ethnicity, and other covariates. In logistic regression models, SSS using each of the four referents was significantly associated with self-rated health, but the model using the referent of others in American society had the strongest association with self-rated health and was the most parsimonious. Findings validate previous studies which typically have used a more distal referent such as others in American society in exploring the SSS-health relationship. However, future work should explore whether this referent is salient to diverse population groups when making social comparisons. Researchers may also want to consider using SSS as an additional status measure since it may capture more subtle differences in the status hierarchy than traditional economic measures.


Neural systems of social comparison and the "above-average" effect

Jennifer Beer & Brent Hughes
NeuroImage, 1 February 2010, Pages 2671-2679

Extant neural models of self-evaluation are dominated by associations with medial prefrontal cortex (MPFC) and posterior cingulate cortex (PCC) function and have mostly been developed from studies differentiating self-evaluation from evaluation of other people. Although self-evaluation is robustly characterized by systematic biases, current neural models of self-evaluation cannot speak to their neurobiology because of a lack of research. The few extant studies have made claims about associations between bias and ventral anterior cingulate cortex (vACC) function but have confounded bias with the valence of experimental stimuli. In study 1, fMRI was used to examine the neurobiology of the "above-average" effect, a robust self-evaluation bias. The majority of people judge their personality to be more desirable (i.e., more positive and less negative traits) than their peers' personalities. MPFC and PCC were significantly more activated by a condition that reduced susceptibility to "above-average" judgments. However, MPFC and PFCC activity were not modulated by individual differences in "above-average" judgments. VACC activity distinguished positive from negative valence but did not predict individual differences in "above-average" judgments. Instead, the extent to which participants viewed themselves as "above average" was negatively correlated with orbitofrontal cortex (OFC) and, to a lesser extent, dorsal anterior cingulate cortex (dACC) activation. A complementary study found that mental load increases "above-average" judgments (study 2). These findings are the first to directly examine the neural systems involved in social judgment bias and have implications for the association between frontal lobe dysfunction and poor insight.


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