Evolutionary biology looks at behavior genetics

a b s t r a c t One leading edge of intellectual exploration that Tom Bouchard significantly contributed to lies at the interface of behavior genetics and evolutionary biology. Behavior geneticists have amply demonstrated that most important psychological individual differences owe part of their variance to genetic variants. An interesting issue from an evolutionary perspective concerns why meaningful genetic variation persists. Evolutionary biology offers a number of possible answers. I examine arguments and currently available data that speak to their application to variation in personality. Some likely answers (e.g., stabilizing selection is opposed by generation of new mutations) were conjectured b

Menstrual cycle variation in women’s preference for the scent of symmetrical men.

Evidence suggests that female sexual preferences change across the menstrual cycle. Women's extra-pair copulations tend to occur in their most fertile period, whereas their intra-pair copulations tend to be more evenly spread out across the cycle. This pattern is consistent with women preferentially seeking men who evidence phenotypic markers of genetic bene¢ts just before and during ovulation. This study examined whether women's olfactory preferences for men's scent would tend to favour the scent of more symmetrical men, most notably during the women's fertile period. College women sni¡ed and rated the attractiveness of the scent of 41 T-shirts worn over a period of two nights by di¡erent men. Results indicated that normally cycling (non-pill using) women near the peak fertility of their cycle tended to prefer the scent of shirts worn by symmetrical men. Normally ovulating women at low fertility within their cycle, and women using a contraceptive pill, showed no signi¢cant preference for either symmetrical or asymmetrical men's scent. A separate analysis revealed that, within the set of normally cycling women, individual women's preference for symmetry correlated with their probability of conception, given the actuarial value associated with the day of the cycle they reported at the time they smelled the shirts. Potential sexual selection processes and proximate mechanisms accounting for these ¢ndings are discussed

How valid are assessments of conception probability in ovulatory cycle research? Evaluations, recommendations, and theoretical implications

Over the past two decades, a large literature examining psychological changes across women's ovulatory cycles has accumulated, emphasizing comparisons between fertile and non-fertile phases of the cycle. While some studies have verified ovulation using luteinizing hormone (LH) tests, counting methods – assessments of conception probability based on counting forward from actual or retrospectively recalled onset of last menses, or backward from actual or anticipated onset of next menses – are more common. The validity of these methods remains largely unexplored. Based on published data on the distributions of the lengths of follicular and luteal phases, we created a sample of 58,000+ simulated cycles. We used the sample to assess the validity of counting methods. Aside from methods that count backward from a confirmed onset of next menses, validities are modest, generally ranging from about .40–.55. We offer power estimates and make recommendations for future work. We also discuss implications for interpreting past research

Pathogen prevalence and human mate preferences

Members of host species in pathogen-host coevolutionary races may be selected to choose mates who possess features of physical appearance associated with pathogen resistance. Human data from 29 cultures indicate that people in geographical areas carrying relatively greater prevalences of pathogens value a mate's physical attractiveness more than people in areas with relatively little pathogen incidence. The relationship between pathogen prevalence and the value people place on physical attractiveness remained strong even after potential confounds such as distance from the equator, geographical region, and average income were statistically controlled for. Discussion focuses on potential limitations of the data, alternative explanations for the findings, and the nature of adaptions to the problems posed by pathogen prevalence.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30928/1/0000598.pd

Rare Copy Number Deletions Predict Individual Variation in Intelligence

Phenotypic variation in human intellectual functioning shows substantial heritability, as demonstrated by a long history of behavior genetic studies. Many recent molecular genetic studies have attempted to uncover specific genetic variations responsible for this heritability, but identified effects capture little variance and have proven difficult to replicate. The present study, motivated an interest in “mutation load” emerging from evolutionary perspectives, examined the importance of the number of rare (or infrequent) copy number variations (CNVs), and the total number of base pairs included in such deletions, for psychometric intelligence. Genetic data was collected using the Illumina 1MDuoBeadChip Array from a sample of 202 adult individuals with alcohol dependence, and a subset of these (N = 77) had been administered the Wechsler Abbreviated Scale of Intelligence (WASI). After removing CNV outliers, the impact of rare genetic deletions on psychometric intelligence was investigated in 74 individuals. The total length of the rare deletions significantly and negatively predicted intelligence (r = −.30, p = .01). As prior studies have indicated greater heritability in individuals with relatively higher parental socioeconomic status (SES), we also examined the impact of ethnicity (Anglo/White vs. Other), as a proxy measure of SES; these groups did not differ on any genetic variable. This categorical variable significantly moderated the effect of length of deletions on intelligence, with larger effects being noted in the Anglo/White group. Overall, these results suggest that rare deletions (between 5% and 1% population frequency or less) adversely affect intellectual functioning, and that pleotropic effects might partly account for the association of intelligence with health and mental health status. Significant limitations of this research, including issues of generalizability and CNV measurement, are discussed

The evolution of human physicalattractiveness

Everywhere the issue has been examined, people make discriminations about others’ physical attractiveness. Can human standards of physical attractiveness be understood through the lens of evolutionary biology? In the past decade, this question has guided much theoretical and empirical work. In this paper, we (a) outline the basic adaptationist approach that has guided the bulk of this work, (b) describe evolutionary models of signaling that have been applied to understand human physical attractiveness, and (c) discuss and evaluate specific lines of empirical research attempting to address the selective history of human standards of physical attractiveness. We also discuss ways evolutionary scientists have attempted to understand variability in standards of attractiveness across cultures as well as the ways current literature speaks to body modification in modern Western cultures. Though much work has been done, many fundamental questions remain unanswered