Identifying and explaining apparent universal sex differences in cognition and behavior

With growing recognition that there are universal sex differences in cognition and behavior, four theories have been proposed to account for these differences: the founder effect theory, the social structuralist theory, the evolutionary theory, and the evolutionary neuroandrogenic (ENA) theory. The latter of these theories is described in considerable detail as offering an explanation for most of 65 recently identified apparent universal sex differences (AUSDs) in cognition and behavior. Regarding “ultimate causes” (why), ENA theory asserts that (a) evolutionary-genetic factors incline females to bias their mate choices toward males who are loyal and competent provisioners of resources and (b) males are merely a genetic variant on the female sex selected for responding to female mating biases. In terms of “proximate causes” (how), the theory maintains that high exposure to androgens has evolved to alter the male brain functioning in two specific ways relative to most female brains: (a) suboptimal arousal and (b) a rightward shift in neocortical functioning. These two functional patterns are described and hypothesized to incline males and females to learn differently in many respects. The most fundamental differences involve males learning ways of either complying with or circumventing female mate preferences. Numerous universal sex differences in cognition and behavior are hypothesized to result from these evolved neurohormonal factors, including most of the 65 AUSDs herein summarized in seven categorical tables.     

Digit ratios and preferences for aggressive content in entertainment

Digit ratios (2D:4D) contain information concerning an individual’s propensity towards aggression. Our study adds the first clue to better understanding the relationship between 2D:4D and exposure to aggressive contents in entertainment products. Our findings suggest that individuals with low 2D:4D prefer aggressive contents such as action films, sports telecast, killing and achieving games, hip-hop music, and erotic video clips rather than do individuals with high 2D:4D. Also individuals with low 2D:4D tend to demonstrate less preference for romance films than individuals with high 2D:4D. In addition, we found that low 2D:4D was associated with a preference for sports instead of other genres of entertainment products. Therefore, 2D:4D (a putative correlate of prenatal sex steroids) helps us to better understand the rationale of individuals’ preferences for media violence.     

Sexual arousal and the pursuit of attractive mating opportunities

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.     

Investigating the Role of Religion‐Supported Secular Programs for Explaining Initiation into First Sex

Research finds that religious youth, compared to less religious youth, are more likely to delay their sexual debut (sometimes until marriage). This study is one of the first to examine the influence of involvement in religion‐supported secular activities for shaping initiation into vaginal sex. Does involvement in religion‐sponsored secular programs produce any health‐related benefits for youth? Using two waves of data from the National Study of Youth and Religion this study finds that among teens who have engaged in some of the precursors to first sex, namely, sexual touching, involvement in religion‐sponsored secular activities is associated with lower odds of having first sex between W1 and W2. Conservative attitudes about sex outside of marriage explain, in part, the relationship. Conversely, network overlap, the number of friends who belong to a youth group, and pressure from friends and partners to have sex do not significantly mediate the relationship.     

The Influence of Sex,Gender, Self-Discrepancies,and Self-Awareness on Anger and Verbal Aggressiveness Among U.S. College Students

Abstract

Among a sample of 445 U.S. college students, the authors examined the extent to which individual differences (e.g., sex, gender, self-discrepancies, self-awareness) explained anger tendencies and verbal aggressiveness. Regression analyses showed that (a) the tendency to repress anger (anger-in) was explained by masculinity, desire to be masculine, and public self-awareness, R ² = .19, F(11, 433) = 8.44, p < .001; (b) the tendency to express anger (anger-out) was explained by sex, masculinity, and public self-awareness, R ² = .17, F(11, 433) = 7.38, p < .001; and (c) willingness to be verbally aggressive was explained by sex, femininity, and private self-awareness, R ² = .32, F(11, 433) = 16.94, p < .001. In addition, different types of individual difference variables accounted for anger tendencies and verbal aggressiveness across sex and gender categories, suggesting that anger and verbal aggressiveness may be driven by different psychological processes across types of participants.     

Effects of pre-trial response requirements on self-control choices by rats and pigeons

Parallel experiments with rats and pigeons examined whether the size of a pre-trial ratio requirement would affect choices in a self-control situation. In different conditions, either 1 response or 40 responses were required before each trial. In the first half of each experiment, an adjusting-ratio schedule was used, in which subjects could choose a fixed-ratio schedule leading to a small reinforcer, or an adjusting-ratio schedule leading to a larger reinforcer. The size of the adjusting ratio requirement was increased and decreased over trials based on the subject's responses, in order to estimate an indifference point-a ratio at which the two alternatives were chosen about equally often. The second half of each experiment used an adjusting-delay procedure-fixed and adjusting delays to the small and large reinforcers were used instead of ratio requirements. In some conditions, particularly with the reinforcer delays, the rats had consistently longer adjusting delays with the larger pre-trial ratios, reflecting a greater tendency to choose the larger, delayed reinforcer when more responding was required to reach the choice point. No consistent effects of the pre-trial ratio were found for the pigeons in any of the conditions. These results may indicate that rats are more sensitive to the long-term reinforcement rates of the two alternatives, or they may result from a shallower temporal discounting rate for rats than for pigeons, a difference that has been observed in previous studies.     

The Effects of Intimacy and Target Sex on Direct Aggression: Further Evidence

The effects on aggression of target sex and relationship with the target were investigated using self‐report data. One hundred and seventy‐four participants (115 female) reported on acts of direct aggression in the last 2 years toward intimate partners, known and unknown same‐sex targets, and known and unknown opposite‐sex targets. Women's self‐reported aggression was higher toward partners than other targets, replicating previous findings regarding women's intimate partner aggression. Women's aggression was consistently higher toward same‐sex than opposite‐sex targets, but the effect of knowing the target was inconsistent. Men's self‐reported aggression was more frequent toward same‐sex than opposite‐sex targets—including intimate partners—and more frequent toward known than unknown targets. Results are discussed with reference to a partner‐specific reduction in women's fear, and sex differences in threshold for classifying someone as “known well.” Limitations of the present sample and suggestions for future work are discussed. Aggr. Behav. 38:272‐280, 2012. © 2012 Wiley Periodicals, Inc.     

Is CAG sequence length in the androgen receptor gene correlated with finger-length ratio?

Manning, Bundred, Newton, and Flanagan reported a significant correlation of .29 in a sample of 50 British males between the length of a repeated sequence on the androgen receptor gene and 2D:4D finger-length ratio on the right hand. We report a 2nd failure to replicate this result. Ours was a sample of 182 Australian male twins studied for other purposes, for whom both measures were available. The result was a nonsignificant correlation of −.055. A similar result was obtained for female twins, and for comparisons within sibling pairs. Correlations are also reported for left hands and right-left differences--the last showed a weak tendency toward replication.     

群体参照效应的验证

该研究全面考虑各种参照条件,选取三个参照群体(家庭、学校、性别),在中国被试身上验证群体参照效应。结果表明:以家庭、学校、性别为参照群体在中国被试身上验证了群体参照效应的存在,而且不同群体群体参照效应的程度不同;同时与选取西方被试研究的比较中得出群体参照效应既存在跨文化的一致性,也存在跨文化的差异性。     

Perceived physical competence and body image as predictors of perceived peer acceptance in adolescents

The purpose of this study was to investigate the relationships among perceived physical competence, body image, and peer acceptance. Body image was considered as a possible mediator of the relationships between perceived physical competence and peer acceptance. Adolescents (N = 838) completed questionnaires. Direct and indirect effects of perceived physical competence and body image on perceived peer acceptance were explored using structural equation modelling. Gender differences were found and the structural mediation model was a reasonable fit to the data; the pattern of relationships in the model was different for adolescent males and females.