Absence makes the adaptations grow fonder: proportion of time apart from partner, male sexual psychology, and sperm competition in humans (Homo sapiens)

Sperm competition occurs when the sperm of multiple males concurrently occupy the reproductive tract of a female and compete to fertilize an egg. We used a questionnaire to investigate psychological responses to the risk of sperm competition for 237 men in committed, sexual relationships. As predicted, a man who spends a greater (relative to a man who spends a lesser) proportion of time apart from his partner since the couple's last copulation reported (a) greater sexual interest in his partner, (b) greater distress in response to his partner's sexual rejection, and (c) greater sexual persistence in response to his partner's sexual rejection. All effects were independent of total time since the couple's last copulation and the man's relationship satisfaction. Discussion addresses limitations of the current research and situates the current results within the broader comparative literature on adaptation to sperm competition.     

Do women perform fellatio as a mate retention behavior?

Men who report performing more mate retention behaviors, in general, and more benefit-provisioning mate retention behaviors, in particular, also report greater interest in, and spend more time, performing oral sex on their female partner. We extended these findings to a female sample to investigate whether women’s oral sex behaviors are related to their mate retention behaviors. We secured self-report data from 410 women residing in the United States or in Germany in a committed, sexual, heterosexual relationship. The results indicate that women who report performing more benefit-provisioning mate retention behaviors also report greater interest in, and spend more time, performing oral sex on their partner. Further, there are no sex differences in the magnitudes or directions of these relationships. The results suggest that both men and women are more interested in, and spend more time, performing oral sex on their partner as part of a benefit-provisioning strategy to increase their partner’s relationship satisfaction. We address limitations of this research, and discuss explanations for the results.     

Exploitative male mating strategies: Personality, mating orientation, and relationship status

Previous research suggests men are sexually attracted to women displaying cues to sexual exploitability. During human evolutionary history, men’s agreeableness, orientation towards casual sex, and relationship status may have been recurrently associated with greater net benefits of pursuing a sexually exploitative strategy. We hypothesized these three individual differences would predict men’s perceptions of women’s sexual exploitability. Seventy-two men viewed photographs of women and rated their sexual exploitability. Men’s agreeableness, sociosexual orientation, and current relationship status interacted to predict their perceptions of women’s sexual exploitability; among unmated men, the combination of low agreeableness and an orientation toward uncommitted sex was associated with higher perceptions of women’s sexual exploitability. This suggests mechanisms motivating sexually exploitative strategies may depend on an interaction between personality characteristics and situational variables.     

Perceived risk of female infidelity moderates the relationship between objective risk of female infidelity and sexual coercion in humans (Homo sapiens)

Female extrapair copulation (EPC) can be costly to a woman's long-term romantic partner. If a woman has copulated recently with a man other than her long-term partner, her reproductive tract may contain the sperm of both men, initiating sperm competition (whereby sperm from multiple males compete to fertilize an egg). Should the woman become pregnant, her long-term partner is at risk of cuckoldry-investing unwittingly in offspring to whom he is not genetically related. Previous research in humans (Homo sapiens) and in nonhuman animals suggests that males have evolved tactics such as partner-directed sexual coercion that reduce the risk of cuckoldry. The current research provides preliminary evidence that mated men (n = 223) at greater risk of partner EPC, measured as having spent a greater proportion of time apart from their partner since the couple's last in-pair copulation, more frequently perform partner-directed sexually coercive behaviors. This relationship is moderated, however, by men's perceived risk of partner EPC, such that the correlation between the proportion of time spent apart since last in-pair copulation and sexually coercive behaviors remains significant only for those men who perceive themselves to be at some risk of partner EPC. Discussion addresses limitations of this research and highlights directions for future research investigating the relationship between female EPC and men's partner-directed sexual coercion.     

Male risk-taking as a context-sensitive signaling device

Evolutionary theorists have suggested that sex differences in risk-taking are due ultimately to greater intrasexual competition among men (compared with women) over access to mating opportunities. The current work provides one of the first direct tests of the hypothesis that risk-taking serves self-presentational functions associated with mating. Results of an experimental study indicated a strong positive relationship between sexual arousal and risk-taking, but only in men exposed to a romantically available female confederate who purportedly would view their risk-taking performance. Findings suggest that risk-taking can serve as a signaling device in the context of mating, that this function is sex-specific, and that it is highly sensitive both to the situational context and to the current psychological state of the risk-taker. This research highlights the utility of an evolutionary approach in understanding the proximate social psychological determinants of risky decision-making.     

Women’s oral sex behaviors and risk of partner infidelity

Pham and Shackelford (2013a) documented that men at greater risk of their partner’s infidelity reported greater interest in and spent more time performing oral sex on their partner. The current study is an extension of their study to a female sample. We recruited 200 women to investigate whether women’s oral sex behaviors are related to the risk of their partner’s infidelity. The results indicate that women at greater risk of partner infidelity did not report more interest in, or spend more time performing, oral sex on their partner. Additionally, the relationships between partner infidelity risk and interest in, and time spent, performing oral sex were greater for men than women. We discuss limitations of this research and discuss explanations for the results.     

Perception of intensity of sperm competition on the part of males

Preferences for certain pornographic themes are hypothesized to have been influenced by our evolutionary history, where sperm competition could play a significant role. The mating system in our australopithecine ancestors, as well as in modern human societies, however, suggests that polygyny (characterized by low risk of sperm competition) has predominated over multi-male multi-female mating systems where high sperm competition is expected. In this study, a sample of men (N = 96) was investigated for their preferences for sexually explicit material showing low (sexual interaction with three women), moderate (one man and one woman) and high intensity of sperm competition (one woman and two men). The participants showed a strong and highly consistent preference for pictures showing moderate and low intensity of sperm competition. These preferences were not influenced by sociosexuality, pornography consumption or attitudes toward pornography. It is suggested that these preferences may mirror psychological adaptations for sperm competition which are activated when the risk of cuckoldry is high. Certain circumstances, where preferences for cues associated with high intensity of sperm competition would be adaptive, are discussed.     

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.     

男性监控配偶、配偶不贞与精子竞争的关系

精子竞争是指同一女性产道中两个或两个以上男人的精子相互竞争卵子的过程。女性得到社会承认的性伙伴可能因精子竞争失败而损失惨重,因为女性私通可能引起男性投资于不携带自己基因的后代。过去研究表明进化而来的男性配偶监控策略可以防止女性不贞,减少精子竞争失败的危险。当前研究发现男性与配偶进行性行为后离别时间越久,男性就越采取出其不意地打电话、独占配偶时间、威胁对配偶感兴趣的男性等手段来监控配偶     

Women’s mate retention behaviors,personality traits,and fellatio

Women perform oral sex on their male partner (i.e., fellatio) as part of a Benefit-Provisioning mate retention strategy, and women’s personality predicts their interest in, and time spent, performing fellatio. We explored whether women’s mate retention behavior mediates the relationship between their personality traits and their performance of fellatio in a long-term romantic relationship. Women (n = 401) reported their personality traits, the frequency with which they performed mate retention behaviors during the past month, and their interest in and the time they spent performing fellatio on their partner during their most recent sexual encounter. The results indicate that women higher in Conscientiousness spend more time performing fellatio on their partner, and this relationship is mediated by their Benefit-Provisioning mate retention. Women higher in Agreeableness report greater interest in performing fellatio on their partner, and less Cost-Inflicting mate retention, but mate retention behaviors do not mediate the relationship between their Agreeableness and their interest in performing fellatio. The current research is the first to investigate the relationship between women’s personality traits and oral sex behaviors, and contributes to research documenting that mate retention strategies are associated with sexual behavior.     

Perceived Physical Attractiveness, Sexual History, and Sexual Intentions: An Internet Study

This study was designed to examine the influence a potential date’s physical attractiveness and sexual history has on an individual’s intentions to engage in safer sex. Over 1,200 participants completed an Internet survey. The questionnaire presented a randomized biography and photograph and asked participants to rate their interest in dating and having a sexual relationship with the target. Participants were randomly assigned to one of six conditions based on the target’s physical attractiveness (low vs. high) and sexual experience (low, medium, or high). Results indicated that men reported greater intentions to have sex than women did, and all participants reported greater likelihood of having sex when the potential partner was highly attractive. Participants rated men and more experienced targets as more risky sexual partners, and the level of a target’s sexual experience was directly related to participants’ willingness to discuss sexual risks. Results indicate a continuing need to include discussion of cognitive factors in all HIV prevention efforts.     

Oral sex as mate retention behavior

Men perform “mate retention” behaviors to reduce the likelihood of their partner’s infidelity. One mate retention strategy men use is to increase their partner’s relationship satisfaction by provisioning her with benefits. We recruited 351 men to investigate whether men perform oral sex on their partner as part of a broader benefit-provisioning mate retention strategy. In support of the predictions, men who reported performing more mate retention behaviors, in general, and more benefit-provisioning mate retention behaviors, in particular, also reported greater interest in and spent more time performing oral sex on their partner. We present limitations of the research and discuss the benefits of an evolutionary perspective for investigating oral sex as a mate retention behavior.     

Male–Female Reactions to Variations in Sexual Explicitness in Pornography: An Empirical Test of Predictions of Intra- and Inter-gender Differences

Previous research has established that men and women respond differently to distinctive characteristics of mediated sexual portrayals. The current study experimentally tests a series of predictions derived from both sperm competition, and minimal parental investment perspectives about between- and within-gender responses to content manipulations of sexually explicit videos. Results indicate that men experienced greater post-exposure arousal and less negative affect after viewing sexually explicit videos than did women. Further, men who viewed more explicit sexual depictions tended to report greater post-exposure arousal than those who saw less explicit depictions. No within-gender differences were found for women in terms of content explicitness. Also, regardless of degree of explicitness, women reported lower levels of post-exposure arousal in response to content depicting male ejaculation than content that does not. Men, though expressing greater post-exposure arousal to less explicit content depicting male sexual climax than that which does not, showed no difference in arousal response when they saw more intensely explicit depictions, whether or not male ejaculation was shown. Findings are discussed in terms of their implications for future application of evolutionary theory in studies of mediated sexual content.     

Forgiveness or breakup: Sex differences in responses to a partner's infidelity

Infidelities--sexual, emotional, or both--afflict many long-term romantic relationships. When a person discovers a partner's betrayal, a major decision faced is to forgive the partner and remain together or to terminate the relationship. Because men and women have confronted different adaptive problems over evolutionary history associated with different forms of infidelity, we hypothesised the existence of sex differences in which aspects of infidelity would affect the likelihood of forgiveness or breakup. We tested this hypothesis using forced-choice dilemmas in which participants (N = 256) indicated how difficult it would be to forgive the partner and how likely they would be to break up with the partner, depending on the nature of the infidelity. Results support the hypothesis that men, relative to women: (a) find it more difficult to forgive a sexual infidelity than an emotional infidelity; and (b) are more likely to terminate a current relationship following a partner's sexual infidelity than an emotional infidelity. The Discussion provides directions for future work on the determinants of breakup and the psychology of forgiveness.     

The affective shift hypothesis: The functions of emotional changes following sexual intercourse

This article develops the Affective Ship Hypothesis, which suggests that women experience positive affective shifts following first‐time intercourse as a means to facilitate a longer‐term, more committed relationship. The hypothesis predicts a negative affective shift in men who pursue a short‐term mating strategy; this shift is hypothesized to function to curtail commitment by motivating the man to terminate the relationship. Study 1 (N= 177) documented sex differences predicted by the affective shift hypothesis. Study 2 (N= 203), using a somewhat different methodology involving reports of presex and postsex feelings, found that men with high numbers of sex partners, but not men with low numbers of partners, experienced a decrease in their partner's physical and sexual attractiveness following first‐time sexual intercourse. In contrast, women, more than men, experienced increases in feelings of love and commitment following first‐time sex.     

Men behaving nicely: Public goods as peacock tails

Insights from sexual selection and costly signalling theory suggest that competition for females underlies men's public good contributions. We conducted two public good experiments to test this hypothesis. First, we found that men contributed more in the presence of an opposite sex audience, but there was no parallel effect for the women. In addition, men's public good contributions went up as they rated the female observer more attractive. In the second experiment, all male groups played a five round public good game and their contributions significantly increased over time with a female audience only. In this condition men also volunteered more time for various charitable causes. These findings support the idea that men compete with each other by creating public goods to impress women. Thus, a public good is the human equivalent of a peacock's tail.     

The relationship of instrumentality and expressiveness to sexual behavior in males and females

In a study of the relationship between gender-relevant personality attributes and sexuality, 259 unmarried males and females completed the short form of the Bem Sex Role Inventory and a detailed survey of their sexual experiences. Multiple regression analyses showed that, for both men and women, instrumental personality attributes were associated with greater sexual experience, including the frequency of sexual intercourse and oral sex, the number of sexual partners, the age at which respondents first had sex, and more relaxed feelings about having sex. Further, interactions of instrumentality and expressiveness revealed that women who scored high in instrumentality but low in expressiveness were consistently more sexually active and experienced than other groups.     

Rejection hurts: The effect of being dumped on subsequent mating efforts

Many of the qualities that people seek in a long-term partner are not directly observable. As a consequence, information gathered through social learning may be important in partner assessment. Here, we tested the hypothesis that finding out potential partners were rejected by their last partner would negatively affect participants' desire to pursue a romantic relationship with them. Results support this hypothesis, and this effect was, as predicted, greater when the target was being evaluated for a potential long-term relationship compared to a sexual relationship. In a more exploratory vein, we tested the effect of the target having rejected their last partner and failing to disclose how their last relationship ended. These scenarios produced intriguing sex differences, such that men's ratings of women fell after learning she had rejected her last partner, but women's ratings of men increased after the same information was introduced. Failing to disclose information about a past relationship was unappealing to both men and women, though particularly so for women.     

Implicit motives and sexual conservatism as predictors of sexual behaviors

This study was designed to provide an assessment of the relationship between the two most important implicit motives and the most frequently studied sexual behaviors. A community sample of 102 men and 92 women completed measures of implicit power and affiliation-intimacy motives, sexual conservatism, social desirability, and sexual behavior. For men, high power motivation was positively associated with the number of sexual partners and the frequency of sex. There was an interaction between sexual conservatism and power motivation in women. For women low in sexual conservatism, high power motivation was positively associated with the number of sexual partners and with earlier initiation to intercourse and oral sex. There were few associations between affiliation-intimacy motivation and sexual behaviors; however, women high in this motive reported later initiation to oral sex.     

Implicit Motives and Sexual Conservatism as Predictors of Sexual Behaviors

ABSTRACT

This study was designed to provide an assessment of the relationship between the two most important implicit motives and the most frequently studied sexual behaviors. A community sample of 102 men and 92 women completed measures of implicit power and affiliation-intimacy motives, sexual conservatism, social desirability, and sexual behavior. For men, high power motivation was positively associated with the number of sexual partners and the frequency of sex. There was an interaction between sexual conservatism and power motivation in women. For women low in sexual conservatism, high power motivation was positively associated with the number of sexual partners and with earlier initiation to intercourse and oral sex. There were few associations between affiliation-intimacy motivation and sexual behaviors; however, women high in this motive reported later initiation to oral sex.