Having the Smarts

Kevin Lewis

November 05, 2009

What Explains Boys' Stronger Confidence in their Intelligence?

Ricarda Steinmayr & Birgit Spinath
Sex Roles, November 2009, Pages 736-749

This study investigated whether boys' stronger confidence in their intelligence is explained by gender differences in measured intelligence and gender-stereotypical parental perceptions of their children's intelligence. Verbal, numeric, figural, and reasoning intelligence and corresponding self-ratings were assessed for 496 German 11th and 12th graders (284 girls; age: M = 16.95). Parents also rated their children's intelligence (339 parents; 205 mothers; age: M  = 46.66). With and without controlling for intelligence, boys rated their numerical, figural, and reasoning abilities higher than girls. The same pattern appeared in parental intelligence perceptions. Boys even judged themselves as more intelligent controlling for both measured intelligence and parental intelligence estimates. Thus, neither intelligence nor gender-stereotypical parental perceptions totally explains boys' stronger confidence in their intelligence.


The Evolution of Overconfidence

Dominic Johnson & James Fowler
University of California Working Paper, September 2009

Confidence is an essential ingredient of success in a wide range of domains including job performance, mental health, sports, business, and combat. Many authors have suggested that overconfidence -- defined here as believing you are better than you are in reality -- is advantageous because it serves to increase ambition, resolve, morale, persistence, and/or the bluffing of opponents. However, too much overconfidence can cause arrogance, market bubbles, financial collapses, policy failures, disasters, and wars, so it remains a puzzle how such a false belief could evolve or remain stable in a population of competing accurate beliefs. Here, we present an evolutionary model that shows overconfidence actually maximizes individual fitness and populations will tend to become overconfident, as long as the resources at stake during conflicts exceed twice the cost of competition. This is because overconfident individuals make more challenges when there is uncertainty about the strength of opponents (and thus the outcome of conflicts), while less confident individuals shy away from many conflicts they would win. Where the value of a prize is at least twice the cost of trying, overconfidence is the best strategy. The model suggests that the conditions under which humans would have evolved to have a "rational" unbiased view of their own capabilities are exceedingly rare, and it helps to explain why resource-rich environments can paradoxically create more conflict. Moreover, the fact that overconfident populations are evolutionarily stable may be one reason why overconfidence persists today in politics, business, and finance, even if it causes occasional disasters.


Genes Determine Stability and the Environment Determines Change in Cognitive Ability During 35 Years of Adulthood

Michael Lyons, Timothy York, Carol Franz, Michael Grant, Lindon Eaves, Kristen Jacobson, Warner Schaie, Matthew Panizzon, Corwin Boake, Hong Xian, Rosemary Toomey, Seth Eisen & William Kremen
Psychological Science, September 2009, Pages 1146-1152

Previous research has demonstrated stability of cognitive ability and marked heritability during adulthood, but questions remain about the extent to which genetic factors account for this stability. We conducted a 35-year longitudinal assessment of general cognitive ability using the Armed Forces Qualification Test administered to 7,232 male twins in early adulthood and readministered to a subset of 1,237 twins during late middle age. The proportion of variance in cognitive functioning explained by genetic factors was .49 in young adulthood and .57 in late middle age. The correlation between the two administrations was .74 with a genetic correlation of 1.0, indicating that the same genetic influences operated at both times. Genetic factors were primarily responsible for stability, and nonshared environmental factors were primarily responsible for change. The genetic factors influencing cognition may change across other eras, but the same genetic influences are operating from early adulthood to late middle age.


Can chimpanzees (Pan troglodytes) discriminate appearance from reality?

Carla Krachun, Josep Call & Michael Tomasello
Cognition, September 2009, Pages 435-450

A milestone in human development is coming to recognize that how something looks is not necessarily how it is. We tested appearance-reality understanding in chimpanzees (Pan troglodytes) with a task requiring them to choose between a small grape and a big grape. The apparent relative size of the grapes was reversed using magnifying and minimizing lenses so that the truly bigger grape appeared to be the smaller one. Our Lens test involved a basic component adapted from standard procedures for children, as well as several components designed to rule out alternative explanations. There were large individual differences in performance, with some chimpanzees' responses suggesting they appreciated the appearance-reality distinction. In contrast, all chimpanzees failed a Reverse Contingency control test, indicating that those who passed the Lens test did not do so by learning a simple reverse contingency rule. Four-year-old children given an adapted version of the Lens test failed it while 4.5-year-olds passed. Our study constitutes the first direct investigation of appearance-reality understanding in chimpanzees and the first cross-species comparison of this capacity.


Pigs learn what a mirror image represents and use it to obtain information

Donald Broom, Hilana Sena & Kiera Moynihan
Animal Behaviour, November 2009, Pages 1037-1041

Mirror usage has been taken to indicate some degree of awareness in animals. Can pigs, Sus scrofa, obtain information from a mirror? When put in a pen with a mirror in it, young pigs made movements while apparently looking at their image. After 5 h spent with a mirror, the pigs were shown a familiar food bowl, visible in the mirror but hidden behind a solid barrier. Seven out of eight pigs found the food bowl in a mean of 23 s by going away from the mirror and around the barrier. Naïve pigs shown the same looked behind the mirror. The pigs were not locating the food bowl by odour, did not have a preference for the area where the food bowl was and did not go to that area when the food bowl was visible elsewhere. To use information from a mirror and find a food bowl, each pig must have observed features of its surroundings, remembered these and its own actions, deduced relationships among observed and remembered features and acted accordingly. This ability indicates assessment awareness in pigs. The results may have some effects on the design of housing conditions for pigs and may lead to better pig welfare.


A Culture of Genius: How an Organization's Lay Theory Shapes People's Cognition, Affect, and Behavior

Mary Murphy & Carol Dweck
Personality and Social Psychology Bulletin, forthcoming

Traditionally, researchers have conceptualized implicit theories as individual differences-lay theories that vary between people. This article, however, investigates the consequences of organization-level implicit theories of intelligence. In five studies, the authors examine how an organization's fixed (entity) or malleable (incremental) theory of intelligence affects people's inferences about what is valued, their self- and social judgments, and their behavioral decisions. In Studies 1 and 2, the authors find that people systematically shift their self-presentations when motivated to join an entity or incremental organization. People present their "smarts" to the entity environment and their "motivation" to the incremental environment. In Studies 3a and 4, they show downstream consequences of these inferences for participants' self-concepts and their hiring decisions. In Study 3b, they demonstrate that the effects are not due to simple priming. The implications for understanding how environments shape cognition and behavior and, more generally, for implicit theories research are discussed.


Cognitive abilities and behavioral biases

Jörg Oechssler, Andreas Roider & Patrick Schmitz
Journal of Economic Behavior & Organization, October 2009, Pages 147-152

We use a simple, three-item test for cognitive abilities to investigate whether established behavioral biases that play a prominent role in behavioral economics and finance are related to cognitive abilities. We find that higher test scores on the cognitive reflection test of Frederick [Frederick, S., 2005. Cognitive reflection and decision-making. Journal of Economic Perspectives 19, 25-42] indeed are correlated with lower incidences of the conjunction fallacy and conservatism in updating probabilities. Test scores are also significantly related to subjects' time and risk preferences. Test scores have no influence on the amount of anchoring, although there is evidence of anchoring among all subjects. Even if incidences of most biases are lower for people with higher cognitive abilities, they still remain substantial.


Is Peer Review in Decline?

Glenn Ellison
MIT Working Paper, July 2007

Over the past decade there has been a decline in the fraction of papers in top economics journals written by economists from the highest-ranked economics departments. This paper documents this fact and uses additional data on publications and citations to assess various potential explanations. Several observations are consistent with the hypothesis that the Internet improves the ability of high-profile authors to disseminate their research without going through the traditional peer-review process.


The Effectiveness of Opposing Expert Witnesses for Educating Jurors about Unreliable Expert Evidence

Lora Levett & Margaret Bull Kovera
Law and Human Behavior, August 2008, Pages 363-374

We tested whether an opposing expert is an effective method of educating jurors about scientific validity by manipulating the methodological quality of defense expert testimony and the type of opposing prosecution expert testimony (none, standard, addresses the other expert's methodology) within the context of a written trial transcript. The presence of opposing expert testimony caused jurors to be skeptical of all expert testimony rather than sensitizing them to flaws in the other expert's testimony. Jurors rendered more guilty verdicts when they heard opposing expert testimony than when opposing expert testimony was absent, regardless of whether the opposing testimony addressed the methodology of the original expert or the validity of the original expert's testimony. Thus, contrary to the assumptions in the Supreme Court's decision in Daubert, opposing expert testimony may not be an effective safeguard against junk science in the courtroom.


Be Too Kind to a Woman, She'll Feel Incompetent: Benevolent Sexism Shifts Self-construal and Autobiographical Memories Toward Incompetence

Muriel Dumont, Marie Sarlet & Benoit Dardenne
Sex Roles, forthcoming

The present study investigated how benevolent (BS) and hostile sexism (HS) shift women's self-construal and autobiographical memory. Belgian undergraduates (only women, N  = 45, mean age = 21.8) were confronted either by BS, HS or neutral comments in the context of a job interview. After performing a cognitive task, participants reported the intrusive thoughts that came to their mind during the task. Later, autobiographical memory for self-incompetence was assessed. Performance response latencies were slower after BS than HS. Also, BS generated more disturbing mental intrusions related to the idea of being incompetent than HS. Autobiographical memory similarly indicated greater access for incompetence after BS. Although HS was more aggressive in tone, it did not shift women's self-construal and autobiographical memories toward incompetence.


Varieties of (Scientific) Creativity: A Hierarchical Model of Domain-Specific Disposition, Development, and Achievement

Dean Keith Simonton
Perspectives on Psychological Science, September 2009, Pages 441-452

Prior research supports the inference that scientific disciplines can be ordered into a hierarchy ranging from the "hard" natural sciences to the "soft" social sciences. This ordering corresponds with such objective criteria as disciplinary consensus, knowledge obsolescence rate, anticipation frequency, theories-to-laws ratio, lecture disfluency, and age at recognition. It is then argued that this hierarchy can be extrapolated to encompass the humanities and arts and interpolated within specific domains to accommodate contrasts in subdomains (e.g., revolutionary versus normal science). This expanded and more finely differentiated hierarchy is then shown to have a partial psychological basis in terms of dispositional traits (e.g., psychopathology) and developmental experiences (e.g., family background). This demonstration then leads to three hypotheses about how a creator's domain-specific impact depends on his or her disposition and development: the domain-progressive, domain-typical, and domain-regressive creator hypotheses. Studies published thus far lend the most support to the domain-regressive creator hypothesis. In particular, major contributors to a domain are more likely to have dispositional traits and developmental experiences most similar to those that prevail in a domain lower in the disciplinary hierarchy. However, some complications to this generalization suggest the need for more research on the proposed hierarchical model.


How Strategic Is the Central Bottleneck: Can It Be Overcome by Trying Harder?

Eric Ruthruff, James Johnston & Roger Remington
Journal of Experimental Psychology: Human Perception and Performance, October 2009, Pages 1368-1384

Recent dual-task studies suggest that a bottleneck prevents central mental operations from working on more than one task at a time, especially at relatively low practice levels. It remains highly controversial, however, whether this bottleneck is structural (inherent to human cognitive architecture) or merely a strategic choice. If the strategic hypothesis is testable, it ought to predict that, under sufficiently strong incentives, people could choose to bypass the bottleneck and perform both tasks in parallel. Because the incentives for parallel processing in previous studies have been modest, the authors introduced a novel dual-task paradigm with much greater incentives, induced by strict time deadlines for each task. With this paradigm, bottleneck delays would cause participants to frequently miss the time deadline or make errors, triggering immediate negative consequences (failure feedback). Nevertheless, participants had little success performing central operations in parallel; severe dual-task performance costs were observed, even with relatively easy tasks. These results greatly strengthen the case that the central bottleneck reflects a structural limitation that, at least at modest practice levels, cannot be avoided merely by trying harder.


Distinct Genetic Influences on Cortical Surface Area and Cortical Thickness

Matthew Panizzon, Christine Fennema-Notestine1, Lisa Eyler, Terry Jernigan, Elizabeth Prom-Wormley, Michael Neale, Kristen Jacobson, Michael Lyons, Michael Grant, Carol Franz, Hong Xian, Ming Tsuang, Bruce Fischl, Larry Seidman, Anders Dale & William Kremen
Cerebral Cortex, November 2009, Pages 2728-2735

Neuroimaging studies examining the effects of aging and neuropsychiatric disorders on the cerebral cortex have largely been based on measures of cortical volume. Given that cortical volume is a product of thickness and surface area, it is plausible that measures of volume capture at least 2 distinct sets of genetic influences. The present study aims to examine the genetic relationships between measures of cortical surface area and thickness. Participants were men in the Vietnam Era Twin Study of Aging (110 monozygotic pairs and 92 dizygotic pairs). Mean age was 55.8 years (range: 51-59). Bivariate twin analyses were utilized in order to estimate the heritability of cortical surface area and thickness, as well as their degree of genetic overlap. Total cortical surface area and average cortical thickness were both highly heritable (0.89 and 0.81, respectively) but were essentially unrelated genetically (genetic correlation = 0.08). This pattern was similar at the lobar and regional levels of analysis. These results demonstrate that cortical volume measures combine at least 2 distinct sources of genetic influences. We conclude that using volume in a genetically informative study, or as an endophenotype for a disorder, may confound the underlying genetic architecture of brain structure.

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