Special Interest
Nicolas Koranyi & Klaus Rothermund
Journal of Experimental Social Psychology, forthcoming
Abstract:
Attention is automatically captured by pictures of physically attractive faces. Although helpful for mate detection, a chronic attentional bias towards attractive opposite-sex faces interferes with relationship initiation because it detracts from the current choice. Therefore, we hypothesized that an orienting of attention to attractive opposite-sex faces is inhibited as soon as a potential mating partner reciprocates one's romantic feelings. Results of two experiments supported this idea: In a first study, imagining that an attractive person shows signs of reciprocal romantic interest eliminated automatic attentional capture by attractive opposite-sex faces. Similar results were obtained in a second study that analyzed intra-individual change in attentional biases during a longitudinal dating study. Results provide evidence for the role of automatic regulatory processes in relationship initiation and can be incorporated into more general models of (implicit) self-regulation.
---------------------
Christine Garver-Apgar et al.
Evolution and Human Behavior, forthcoming
Abstract:
Intralocus sexual conflict (IASC) occurs when sex-specific selection favors genes that increase fitness in one sex and decrease fitness in the other sex. The current study was designed to explore whether IASC occurs in humans. In a sample of siblings, we identified and measured sexually dimorphic traits and hormones within each sex that are related to fitness and are likely coded for by antagonistic genes: waist-to-hip ratio (WHR) and breast size in women, WHR and bicep size (an index of muscularity) in men, and estradiol (E) and testosterone (T) in both sexes. If these traits and hormones are coded for by genes under IASC, masculine or feminine expression of traits and hormones should differentially predict brothers' and sisters' fitness. Consistent with an IASC model, both men and women who were physically masculine for their sex reported higher mate value brothers relative to sisters. Similarly, in normal-weight individuals, E levels positively predicted the mate value of sisters relative to brothers and T levels positively predicted the mate value of brothers relative to sisters. We found no evidence that individuals with indicators of high genetic quality (i.e., physically masculine men and physically feminine women) share high mate value with all siblings, regardless of sibling sex. Results are novel and demonstrate for the first time that intralocus conflict in humans may influence the fitness of related individuals.
---------------------
Why Don't Smart Teens Have Sex? A Behavioral Genetic Approach
Kathryn Harden & Jane Mendle
Child Development, forthcoming
Abstract:
Academic achievement and cognitive ability have been shown to predict later age at first sexual intercourse. Using a sample of 536 same-sex twin pairs who were followed longitudinally from adolescence to early adulthood, this study tested whether relations between intelligence, academic achievement, and age at first sex were due to unmeasured genetic and environmental differences between families. Twins who differed in their intelligence or their academic achievement did not differ in their age at first sex. Rather, the association between intelligence and age at first sex could be attributed entirely to unmeasured environmental differences between families, whereas the association between academic achievement and age at first sex could be attributed entirely to genetic factors.
---------------------
The Trouble with Thinking: People Want to Have Quick Reactions to Personal Taboos
Anna Merritt & Benoît Monin
Emotion Review, July 2011, Pages 318-319
Abstract:
If lay theories associate moral intuitions with deeply held values, people should feel uncomfortable relying on deliberative thinking when judging violations of personal taboos. In two preliminary studies, participants with siblings of the opposite sex were particularly troubled when evaluating a sibling incest scenario under instructions to think slowly and rationally, or when the scenario was presented in a hard-to-read font forcing them to employ deliberative processing. This suggests that we may be intuitive intuitionists, and opens the door for investigations of people's preferred modes of moral judgment.
---------------------
Is There a Sensitive Period in Human Incest Avoidance?
Liqun Luo
Evolutionary Psychology, June 2011, Pages 285-295
Abstract:
Many studies support the proposition that early cosocialization with opposite-sex children has the effect of inhibiting later mutual sexual attraction, but the existence of a period in the life cycle in which individuals are sensitive to the effect of early cosocialization has been a matter of controversy. Drawing on earlier traditional psychological research, and on more recent work guided by parental investment theory, we hypothesized that only for maternal perinatal association (MPA)-absent males a less-than-around-three-years age difference with the sister can predict stronger aversion to sibling incest. The results corroborated the hypothesis. The results can be interpreted as support for the existence of a sensitive period as well as for the potent role of MPA. Cross-cultural comparative studies were called on to further test the hypothesis.
---------------------
Are sexualized women complete human beings? Why men and women dehumanize sexually objectified women
Jeroen Vaes, Paola Paladino & Elisa Puvia
European Journal of Social Psychology, forthcoming
Abstract:
Focusing on the dehumanization of sexually objectified targets, study 1 tested the extent to which objectified and non-objectified male and female publicity photos were associated with human compared to animal concepts. Results confirmed the hypothesis that, among all targets, only objectified women were associated with less human concepts. This pattern of results emerged for both male and female participants but likely for different reasons. Study 2 directly looked at female and male participants' affinity with sexually objectified women. Results indicated that the more women distanced themselves from sexually objectified women the more they dehumanized them, whereas men's sexual attraction moderated their tendency to dehumanize female targets. In study 3, this latter motivation was operationalized as the activation of a sex goal and showed to trigger man's but not woman's dehumanization of female targets. Overall, the present set of studies show that only sexually objectified women are dehumanized by both men and women but for different reasons. Whereas sexual attraction shifts a men's focus of a female target away from her personality onto her body triggering a dehumanization process, women are more inclined to dehumanize their sexually objectified counterparts the more they distance themselves from these sexualized representations of their gender category.
---------------------
Do scientific theories affect men's evaluations of sex crimes?
Ilan Dar-Nimrod et al.
Aggressive Behavior, forthcoming
Abstract:
Evolutionary psychology accounts of gender differences in sexual behaviors in general and men's sexual aggression, in particular, has been criticized for legitimizing males' sexual misconduct. To empirically assess such critiques, two studies examined how men's judgments of male sex crimes (solicitation of sex from a prostitute; rape) are influenced by exposure to (a) evolutionary psychological theories and (b) social-constructivist theories. Across two studies, a consistent pattern emerged compared with a control condition (a) exposure to evolutionary psychology theories had no observable impact on male judgments of men's criminal sexual behavior, whereas (b) exposure to social-constructivist theories did affect judgments, leading men to evaluate sex crimes more harshly. Additional results (from Study 2) indicate that this effect is mediated by perceptions of male control over sexual urges. These results have implications for journalists, educators, and scientists.
---------------------
Sexual arousal and the pursuit of attractive mating opportunities
Emily Stone, Todd Shackelford & Aaron Goetz
Personality and Individual Differences, forthcoming
Abstract:
From an evolutionary perspective, sexual arousal may function, in part, to motivate the pursuit of attractive mating opportunities. We designed a study to test three aspects of this hypothesis. Several hundred heterosexual men and women completed a short survey about sexual arousal in response to a casual sex mating opportunity. We replicated previous research documenting that men report greater sexual arousal than women in response to a short-term mating opportunity. We argue that it is unlikely that a "downplaying of alternatives" psychology evolved, whereby mated individuals rate opposite-sex targets as less attractive than do unmated individuals, but instead that men and women have a relationship-seeking psychology, motivating them to pursue attractive mating opportunities. The results supported this relationship-seeking psychology rather than a downplaying alternatives psychology. Discussion addresses directions for future research on the motivational properties of sexual arousal.
---------------------
David Puts et al.
Evolution and Human Behavior, forthcoming
Abstract:
It has been hypothesized that female orgasm evolved to facilitate recruitment of high-quality genes for offspring. Supporting evidence indicates that female orgasm promotes conception, although this may be mediated by the timing of female orgasm in relation to male ejaculation. This hypothesis also predicts that women will achieve orgasm more frequently when copulating with high-quality males, but limited data exist to support this prediction. We therefore explored relationships between the timing and frequency of women's orgasms and putative markers of the genetic quality of their mates, including measures of attractiveness, facial symmetry, dominance, and masculinity. We found that women reported more frequent and earlier-timed orgasms when mated to masculine and dominant men-those with high scores on a principal component characterized by high objectively-measured facial masculinity, observer-rated facial masculinity, partner-rated masculinity, and partner-rated dominance. Women reported more frequent orgasm during or after male ejaculation when mated to attractive men-those with high scores on a principal component characterized by high observer-rated and self-rated attractiveness. Putative measures of men's genetic quality did not predict their mates' orgasms from self-masturbation or from non-coital partnered sexual behavior. Overall, these results appear to support a role for female orgasm in sire choice.
---------------------
Lisa DeBruine et al.
Proceedings of the National Academy of Sciences, forthcoming
Abstract:
Contextual cues of genetic relatedness to familiar individuals, such as cosocialization and maternal-perinatal association, modulate prosocial and inbreeding-avoidance behaviors toward specific potential siblings. These findings have been interpreted as evidence that contextual cues of kinship indirectly influence social behavior by affecting the perceived probability of genetic relatedness to familiar individuals. Here, we test a more general alternative model in which contextual cues of kinship can influence the kin-recognition system more directly, changing how the mechanisms that regulate social behavior respond to cues of kinship, even in unfamiliar individuals for whom contextual cues of kinship are absent. We show that having opposite-sex siblings influences inbreeding-relevant perceptions of facial resemblance but not prosocial perceptions. Women with brothers were less attracted to self-resembling, unfamiliar male faces than were women without brothers, and both groups found self-resemblance to be equally trustworthy for the same faces. Further analyses suggest that this effect is driven by younger, rather than older, brothers, consistent with the proposal that only younger siblings exhibit the strong kinship cue of maternal-perinatal association. Our findings provide evidence that experience with opposite-sex siblings can directly influence inbreeding-avoidance mechanisms and demonstrate a striking functional dissociation between the mechanisms that regulate inbreeding and the mechanisms that regulate prosocial behavior toward kin.
---------------------
Samantha Goodin et al.
Sex Roles, July 2011, Pages 1-12
Abstract:
Objectification theory (Fredrickson and Roberts 1997) proposes that women from Western cultures are widely portrayed and treated as objects of the male gaze, leading to the development of self-objectification, in which girls and women internalize these societal messages and view their own bodies as objects to be evaluated according to narrow standards of (often sexualized) attractiveness. Prompted by findings from the American Psychological Association Task Force on the Sexualization of Girls (APA 2007), the present study considers girls' clothing as a possible socializing influence that may contribute to the development of self-objectification in preteen girls. Accordingly, in this content analysis, we examined the frequency and nature of "sexualizing" clothing available for girl children (generally sizes 6-14) on the websites of 15 popular stores in the US. Sexualizing clothing was defined as clothing that revealed or emphasized a sexualized body part, had characteristics associated with sexiness, and/or had sexually suggestive writing. Clothing was also coded for childlike characteristics, such as child-like fabric (e.g., polka dot pattern) or a modest, non-revealing cut. Across all stores and all articles of clothing, 69% of the clothing items were coded as having only childlike characteristics, 4% as having only sexualizing characteristics, 25.4% as having both sexualizing and childlike characteristics, and 1% as having neither sexualizing nor childlike characteristics. "Tween" stores like Abercrombie Kids had the highest proportion of sexualizing clothing. The findings are discussed within the framework of the development of self-objectification.
---------------------
Rape, sex partnership, and substance use consequences in women veterans
Brenda Booth et al.
Journal of Traumatic Stress, June 2011, Pages 287-294
Abstract:
The association of rape history and sexual partnership with alcohol and drug use consequences in women veterans is unknown. Midwestern women veterans (N = 1,004) completed a retrospective telephone interview assessing demographics, rape history, substance abuse and dependence, depression, and posttraumatic stress disorder (PTSD). One third met lifetime criteria for substance use disorder (SUD), half reported lifetime completed rape, a third childhood rape, one quarter in-military rape, 11% sex with women. Lifetime SUD was higher for women with rape history (64% vs. 44%). Women with women as sex partners had significantly higher rates of all measures of rape, and also lifetime substance use disorder. Postmilitary rape, sex partnership, and current depression were significantly associated with lifetime SUD in multivariate models (odds ratio = 2.3, 3.6, 2.1, respectively). Many women veterans have a high need for comprehensive mental health services.
---------------------
Paul Eastwick, Eli Finkel & Alice Eagly
Journal of Personality and Social Psychology, forthcoming
Abstract:
Three studies explored how the traits that people ideally desire in a romantic partner, or ideal partner preferences, intersect with the process of romantic relationship initiation and maintenance. Two attraction experiments in the laboratory found that, when participants evaluated a potential romantic partner's written profile, they expressed more romantic interest in a partner whose traits were manipulated to match (vs. mismatch) their idiosyncratic ideals. However, after a live interaction with the partner, the match vs. mismatch manipulation was no longer associated with romantic interest. This pattern appeared to have emerged because participants reinterpreted the meaning of the traits as they applied to the partner, a context effect predicted by classic models of person perception (S. E. Asch, 1946). Finally, a longitudinal study of middle-aged adults demonstrated that participants evaluated a current romantic partner (but not a partner who was merely desired) more positively to the extent that the partner matched their overall pattern of ideals across several traits; the match in level of ideals (i.e., high vs. low ratings) was not relevant to participants' evaluations. In general, the match between ideals and a partner's traits may predict relational outcomes when participants are learning about a partner in the abstract and when they are actually in a relationship with the partner, but not when considering potential dating partners they have met in person.
---------------------
Friederike Kachel, L.S. Premo & Jean-Jacques Hublin
American Journal of Human Biology, July/August 2011, Pages 479-487
Objectives: Human life history is unique among primates. Despite our extended lifespan, the length of the female reproductive period is shorter in humans than in our closest living relatives, chimpanzees. Here, we investigate whether this difference could be explained by another unique aspect of human life history - a young weaning age.
Methods: Age-dependent female fertility is modeled with the Brass polynomial. We model female reproductive period length as single locus with multiple alleles. Selection acts on the length of the female reproductive period in an evolutionary agent-based simulation. We quantify the effect of weaning age on the optimal length of the female reproductive period under a range of adult mortality rates.
Results: Females sacrifice a smaller proportion of their reproductive potential due to nursing by weaning their offspring at younger ages. As a consequence, the optimal length of the female reproductive period decreases as weaning age decreases, even when adult mortality is low.
Conclusions: Natural selection will favor mutations or strategies that can decrease weaning age without incurring fitness costs. In the presence of younger weaning ages, selection favors a shorter female reproductive period. To the extent that allocare can decrease weaning age without decreasing fitness, its ubiquity in human societies and near absence in other primate societies may explain why women have a shorter reproductive period. Furthermore, allocare may have provided human ancestors with an avenue to decreased weaning age-and, ultimately, a shorter female reproductive period-that was unavailable to their hominoid contemporaries.
---------------------
Vaginal Orgasm Is More Prevalent Among Women with a Prominent Tubercle of the Upper Lip
Stuart Brody & Rui Miguel Costa
Journal of Sexual Medicine, forthcoming
Introduction: Recent studies have uncovered multiple markers of vaginal orgasm history (unblocked pelvic movement during walking, less use of immature psychological defense mechanisms, greater urethrovaginal space). Other markers (perhaps of prenatal origin) even without obvious mechanistic roles in vaginal orgasm might exist, and a clinical observation led to the novel hypothesis that a prominent tubercle of the upper lip is such a marker.
Aims: To examine the hypothesis that a prominent tubercle of the upper lip is associated specifically with greater likelihood of experiencing vaginal orgasm (orgasm elicited by penile-vaginal intercourse [PVI] without concurrent masturbation).
Methods: Women (N = 258, predominantly Scottish) completed an online survey reporting their frequencies of various sexual activities and corresponding orgasms, age, and the prominence of the tubercle of their upper lip. Social desirability response bias was also assessed.
Main Outcome Measures: Multivariate associations of lip tubercle prominence with vaginal orgasm (ever and past month consistency) and with orgasm by other means.
Results: A prominent and sharply raised lip tubercle was associated with greater odds (odds ratio = 12.3) of ever having a vaginal orgasm, and also with greater past month vaginal orgasm consistency (an effect driven by the women who never had a vaginal orgasm), than less prominent lip tubercle categories. Lip tubercle was not associated with social desirability responding, or with orgasm triggered by masturbation during PVI, solitary or partner clitoral or vaginal masturbation, vibrator, or cunnilingus.
Conclusions: The results are discussed in light of the unique nature of vaginal orgasm and the possibility of prenatal developmental influences.