Sex and Sexual Orientation Differences in Dark Triad Traits, Sexual Excitation/Inhibition, and Sociosexuality.

The present study sought to investigate sex and sexual orientation differences in several traits related to sexuality and sexual behavior. Examining sexual orientation differences alongside basic sex differences to help identify correlates of sexual orientation diversity, and whether individuals with varying degrees of same-sex attraction show concurrent sex-atypical shifts in other domains. Males tend to score higher than females in the Dark Triad (DT) traits of sub-clinical narcissism, psychopathy, and Machiavellianism. Similarly, females tend to be more cautious than males in their attitudes and desires toward casual sex activity (i.e., sociosexuality). These sex differences may be related to the propensity for individuals to become easily sexually excited, which is higher in males, or to instead inhibit sexual arousal, which is higher in females. In a large undergraduate sample (N = 2047), we replicated expected sex differences in DT traits, sociosexuality, and sexual excitation/inhibition. We found that non-heterosexual females were "male-shifted" in some of these traits, but these shifts tended to be strongest among mostly heterosexual and bisexual individuals. Furthermore, we found that within-sex variation in sociosexuality, sexual excitation, and sexual inhibition was not related to sexual orientation in a linear fashion. Instead, sociosexuality and sexual excitation were related to sexual orientation in a curvilinear (inverted-U) fashion, especially among females. The fact that traits correlated with bisexuality and homosexuality were somewhat distinct is consistent with the idea that different developmental pathways may lead to these discrete sexual attraction patterns.

Why I teach the controversy: using creationism to teach critical thinking.

Creationism and intelligent design are terms used to describe supernatural explanations for the origin of life, and the diversity of species on this planet. Many scientists have argued that the science classroom is no place for discussion of creationism. When I began teaching I did not teach creationism, as I focused instead on my areas of expertise. Over time it became clear that students had questions about creationism, and did not understand the difference between a scientific approach to knowledge and non-scientific approaches. This led me to wonder whether ignoring supernatural views allowed them to remain as viable "alternatives" to scientific hypotheses, in the minds of students. Also, a psychology class is an ideal place to discuss not only the scientific method but also the cognitive errors associated with non-science views. I began to explain creationism in my classes, and to model the scientific thought process that leads to a rejection of creationism. My approach is consistent with research that demonstrates that teaching content alone is insufficient for students to develop critical thinking and my admittedly anecdotal experience leads me to conclude that "teaching the controversy" has benefits for science students.

Human preferences for sexually dimorphic faces may be evolutionarily novel.

A large literature proposes that preferences for exaggerated sex typicality in human faces (masculinity/femininity) reflect a long evolutionary history of sexual and social selection. This proposal implies that dimorphism was important to judgments of attractiveness and personality in ancestral environments. It is difficult to evaluate, however, because most available data come from large-scale, industrialized, urban populations. Here, we report the results for 12 populations with very diverse levels of economic development. Surprisingly, preferences for exaggerated sex-specific traits are only found in the novel, highly developed environments. Similarly, perceptions that masculine males look aggressive increase strongly with development and, specifically, urbanization. These data challenge the hypothesis that facial dimorphism was an important ancestral signal of heritable mate value. One possibility is that highly developed environments provide novel opportunities to discern relationships between facial traits and behavior by exposing individuals to large numbers of unfamiliar faces, revealing patterns too subtle to detect with smaller samples.

Long lasting effects of rearing by an ethanol-consuming dam on voluntary ethanol consumption by rats.

For exposure to alcohol early in life to potentiate alcohol abuse in adolescence or adulthood, consequences of early exposure to alcohol must be of considerable duration. In two experiments using Norway rats as subjects, we examined effects of exposure during weaning to a dam consuming ethanol on adolescents' later affinity for ethanol. In a preliminary experiment, we offered rat pups a choice between 8% ethanol and water for 7 days immediately after they were weaned at 26 days of age. Pups whose dam had ingested 8% ethanol for 6 days either immediately or 1 week before we weaned them drank more ethanol than pups whose dam drank only water during the same period. Independent groups of rats reared by a dam consuming 8% ethanol from postnatal days 18 to 26 and tested 1, 2, 4 or 6 weeks later all drank significantly more 8% ethanol at testing than did pups whose dam drank only water. Our data also provided confirmation of previous reports of an experience-independent greater affinity for ethanol in younger rats.

Effects of ethanol consumption by adult female rats on subsequent consumption by adolescents.

We used a two-bottle choice test to measure voluntary ethanol consumption by adolescent rats that had lived with ethanol-consuming or water-consuming adult conspecifics. We found that housing weanlings with either a virgin or a lactating adult female rat that ingested ethanol increased the weanlings' subsequent voluntary intake of ethanol when they were fluid-deprived and provided with choices between 8% ethanol solution and water for 2 h/day. Rats housed with both an ethanol-consuming virgin female and their water-consuming dam drank more ethanol than did rats housed with a dam and virgin female, both consuming water. Rats housed with an ethanol-consuming dam and ethanol consuming adult virgin did not drink more ethanol than did rats housed with an ethanol-consuming dam and a water-consuming virgin female. In sum: (1) young rats learned socially to consume ethanol. (2) Exposure to ethanol in mother's milk was not necessary for such social learning to occur, and (3) living with an ethanol-consuming unfamiliar, virgin female conspecific resulted in enhanced ethanol intake by adolescent rats, even if a water-consuming dam was also present.

Ethanol consumption by rat dams during gestation, lactation and weaning increases ethanol consumption by their adolescent young.

In two experiments, we examined effects of ethanol consumption in rat dams during gestation, lactation, and weaning on voluntary ethanol consumption by their adolescent young. We found that exposure to an ethanol-ingesting dam throughout gestation, lactation, and weaning enhanced voluntary ethanol consumption by 26- to 33-day-old adolescents. We systematically examined effects on adolescent ethanol intake or requiring dams to drink ethanol during various periods in their pups' development. We found that exposure to an ethanol-consuming dam during weaning enhanced adolescent ethanol consumption and exposure to a dam drinking ethanol during either gestation or while nursing enhanced adolescents' ethanol consumption only if pups also had access to ethanol during the weaning period.