The Ape That Thought It Was a Peacock: Does Evolutionary Psychology Exaggerate Human Sex Differences?

This article looks at the evolution of sex differences in sexuality in human beings and asks whether evolutionary psychology sometimes exaggerates these differences. According to a common understanding of sexual selection theory, females in most species invest more than males in their offspring, and as a result, males compete for as many mates as possible, whereas females choose from among the competing males. The males-compete/females-choose (MCFC) model applies to many species but is misleading when applied to human beings. This is because males in our species commonly contribute to the rearing of the young, which reduces the sex difference in parental investment. Consequently, sex differences in our species are relatively modest. Rather than males competing and females choosing, humans have a system of mutual courtship: Both sexes are choosy about long-term mates, and both sexes compete for desirable mates. We call this the mutual mate choice (MMC) model. Although much of the evolutionary psychology literature is consistent with the MMC model, the traditional MCFC model exerts a strong influence on the field, distorting the emerging picture of the evolved sexual psychology of Homo sapiens. Specifically, it has led to the exaggeration of the magnitude of human sex differences, an overemphasis on men's short-term mating inclinations, and a relative neglect of male mate choice and female mate competition. We advocate a stronger focus on the MMC model.     

Mate choice in the domestic cat (Felis silvestris catus L.)

The domestic cat (Felis silvestris catus L.) has colonized different types of environments that differ in their spatial distribution of resources. Urban environments are characterized by highly clumped distributions of food and shelter, allowing domestic cats to live in large multimale‐multifemale groups. In such a situation, questions arise about male and female mating strategies. In particular, do females exert active mate choice? We tested this question using behavioural records on acceptance and refusal of males by estrous females. Our results showed that most females copulated with several males during a single estrus period. The variability of female behaviour was high: six females copulated with all courting males whereas three others mated with most courting males; six others copulated with half or less of the courting males. Even if some females copulated with certain males more often than with others, the identity of the most successful males changed each time. These results show that most females did not choose mates among different males available. The results are discussed in terms of optimal reproductive strategies of males and females in an urban environment. Aggr. Behav. 26:455–465, 2000. © 2000 Wiley‐Liss, Inc.     

Identifying the ideal mate: More evidence for male-female convergence

Male and female students participated in an experiment designed to test specific hypotheses fromsexual strategies theory (Buss & Schmitt, 1993) regarding their preferences for certain personal and physical traits in a potential mate. Participants distributed 50 points among a number of trait-pairs. The items consisted of a consensually valued trait-pair, “biologically relevant” trait-pairs, and a reference to ethnic and cultural similarity. In Condition 1 participants distributed the points among the trait-pairs without any additional information about the potential mate; Condition 2 participants distributed the points after being asked to assume the potential mate possessed some biologically relevant traits. Males, compared to females, assigned more points to trait-pairs signalling highreproductive value, and females, compared to males, assigned more points to trait-pairs signalling highresource potential. Male and female participants in Condition 2, compared to control participants, distributed more points among the opposite genders’ preferred traits. Discussion focused on speculation that assuming a potential mate possessed biologically relevant traits increases the desirability of other traits related to the solution of common and genderspecific long-term mating problems.     

The role of scent marks in female choice of territories and refuges in a lizard (Podarcis hispanica)

Female mate choice based on male phenotypic traits is controversial in lizards, particularly in territorial species. In this study, we examine female choice of male scent marks in a territorial lacertid lizard (Podarcis hispanica) in which scent marks have been shown to signal male size (i.e., an important determinant of competitive ability in this species). Females were simultaneously exposed to three naturalized 4 m2 choice areas bearing: (1) no scent marks (i.e., control), (2) scent marks of large males, and (3) scent marks of small males. Although female lizards preferentially associated with scent marked choice areas, we found no evidence that females chose territories marked by large males. Furthermore, in response to experimentally induced dusk at the end of choice trials, females preferentially took shelter in refuges scent marked by small males. Our results suggest that, like males in this species, females are able to use male scent marks to assess the body size of resident territorial males, but do not show a preference for territories occupied by large males.     

繁衍线索对风险信息加工的影响

进化理论认为风险行为与求偶有关。研究通过比较求偶信息(异性照片或描述异性的词语)、养育后代(孕妇照片)及奖赏信息(金牌照片等)试图进一步探讨繁衍线索对两性知觉和判断风险信息的影响。研究1中, 被试描述理想约会对象后求偶动机得到激发, 相对于描述晴朗天气的控制组, 求偶动机让两性更慢地从高风险信息(如滑雪、冲浪等)转移注意力, 且两性对风险信息的注意转移与社群性向无关。研究2显示, 相对于养育后代和奖赏信息, 求偶信息更为迅速地促使男性对高风险信息做出判断, 但求偶信息让女性比男性更慢地对高风险信息做出判断。研究结果进一步证实了自然选择理论及性选择理论对两性加工风险信息的认知机制具有预测作用。     

君子不夺人所好？择偶动机启动下的男性择偶复制

考察择偶动机启动下男女的择偶复制发生情况,及目标面孔吸引力对男性择偶复制的调节作用。结果：(1)女性易发生择偶复制;(2)男性的择偶复制会受择偶动机启动的影响,但这种影响仅限于目标面孔吸引力处于中、低水平时。结论：男性在特定情景中可发生择偶复制,这是更为复杂的、经多种信息评估的结果。     

A Brain of Her Own: A Neural Correlate of Song Assessment in a Female Songbird

The song control region in the avian forebrain is a series of discrete, interconnected nuclei mediating song learning and production. It has been studied in males or in species where both sexes sing. Little is known about the neural correlates of song perception in nonsinging females, often the intended recipients of song. We studied cowbirds (Molothrus ater), a species in which only males sing but in which females discriminate between males on the basis of song. We focused on nucleus lMAN because it has been implicated in early song acquisition, a stage relevant to both sexes to choose among competing acoustic models. We found that volume of lMAN was monomorphic in cowbirds. Moreover, the volume and neuronal number of female lMAN were positively correlated with selectivity of copulatory responding. The results provide strong evidence of nonsinging female's use of “song” control nuclei for song perception without the possibility of song production.     

A Comparison of the Neurotic Tendencies of Students of Different Racial Ancestry in Hawaii

ABSTRACT

Research has shown that altruism plays a role in mate choice, and recent studies suggest it is most important for long-term relationships. This study examined whether altruism is preferred for long-term relationships for both males and females. This was achieved using two versions of the Mate Preferences Towards Altruistic Traits (MPAT) scale that assessed preferences for short-term and long-term relationships. Both males and females significantly preferred altruistic mates for long-term relationships, and the size of this preference was greater than for other traits in mate choice. This provides support for previous findings that state that altruism conveys information about an individual's partner/parenting qualities or good character.     

Chinese undergraduates' preferences for altruistic traits in mate selection and personal advertisement: Evidence from Q‐sort technique

Human's preferences for altruistic mates have been confirmed by many researchers. Under the deep influence of Confucianism that authorised more parental control over offspring's mate selection, Chinese people's mating strategies and mate preferences may be different from what the evolutionary psychologists have suggested. This study used the Q‐sort technique to assess the roles of altruistic traits in mate selection and personal advertisement. A total of 200 university students participated in the Q‐sort procedures and were asked to sort 50 traits (among which altruistic traits were mixed) according to their importance when choosing (or advertising to) a long‐term (LT) or a short‐term (ST) mate. Our findings were quite different from prior studies. When Chinese participants chose a mate or advertised themselves to a potential mate, kin altruism was considered to be the most important trait; altruistic traits were more preferred by males than by females and females tended to advertise themselves as more altruistic; preferences for altruistic traits showed no difference between LT and ST mate selections (or between personal advertisement to a LT and a ST mate).     

Visual preferences for sex and status in female rhesus macaques

Most primates are both highly visual and highly social. These qualities predict that visual cues to social variables, such as identity, sex, social status, and reproductive quality, would be intrinsically valuable and systematically attract attention. Supporting this idea, thirsty male rhesus macaques (Macaca mulatta) will forego fluid reward to view images of the faces of high-ranking males and the sexual skin of females. Whether female rhesus macaques, who experience dramatically different social pressures and reproductive costs than male macaques, also systematically and spontaneously value visual cues to social information remains untested experimentally. We probed the preferences of female rhesus macaques, given the opportunity to display an image from a known class of social stimuli or touch a second target to display a blank screen. We found that females preferred faces of high-status males and also images of the perinea of both males and females, but were not motivated to display images of subordinate males or control stimuli. These findings endorse the view that both male and female rhesus macaques—and presumably other highly social primates—seek information about other individuals in a way that matches the adaptive value of that information for guiding social behavior.     

Parent‐offspring conflict in Japan and parental influence across six cultures

Previous research has demonstrated that parents and children often have conflicting mate preferences. The present research was conducted among 443 Japanese university students. Using an existing scale designed to uncover parent‐offspring conflict over mate choice, the results revealed that children perceived having a potential partner with traits connoting poor genetic quality as being more unacceptable to themselves, and having a potential partner with traits connoting low parental investment and cooperation with the ingroup as being more unacceptable to their parent. A number of sex differences emerged. The highest potential for parent‐offspring conflict existed between female offspring and their father, and female offspring also rated traits connoting low social status as being more unacceptable to their parents, particularly to the father.     

Differences in affiliative behavior, pair bonding, and vaginal cytology in two species of vole (Microtus ochrogaster and M. montanus)

Prairie voles (Microtus ochrogaster) and montane voles (M. montanus) display marked differences in social organization in the field. Trios of 1 male and 2 females were studied in a large enclosure for a 10-day period. Prairie voles spent 59% of the observation time in side-by-side contact, whereas montane voles spent only 7% of the time in contact. Vaginal smears indicated female-female suppression of estrus in prairie voles; female montane voles appeared to cycle in the presence of males. Male prairie voles preferentially paired and nested with 1 of the females, and vaginal estrus generally followed pair formation by 2 days. Male montane voles did not spend time preferentially with either female, even after mating. These results suggest that the contrasting mating systems of these species result from differences in the propensity for affiliative behavior and social bonding rather than from mate availability or female receptivity.     

Should have known better: The impact of mating experience and the desire for marriage upon attraction to the narcissistic personality

Narcissistic males do not make good romantic partners. Narcissistic males lack commitment, engage in manipulative game-playing and are unfaithful. Despite this, they are still desired by females. Females value different traits in short-term and long-term partners. Previous mate sampling experience is also important to facilitate mate assessment. This study aimed to determine whether amongst young adult heterosexual females; their mate sampling experience and desire for marriage influenced their attraction to narcissistic personality traits in a potential mate. British females aged 18–28 provided information on past mating experience, future desire for marriage and rated their agreement with 20 statements relating to the extent that they found narcissistic personality traits attractive in a potential mate. Females with greater mating experience and those desiring marriage were more attracted to the narcissistic male personality. The narcissistic personality, whilst having many negative qualities, possesses qualities associated with status and resource provision. These traits are desirable in short and long-term mating contexts. Despite future long-term mating desires which are unlikely to be achieved with a narcissistic male and possession of substantial mate sampling experience, females view the narcissistic male as a suitable partner: a testament to the success of the narcissistic personality in facilitating short-term mating.     

Youths’ attributions for power-related gender differences: nature,nurture, or God?

This study examined beliefs about power-related gender traits among 73 early adolescents in middle school (M age=12.5), 84 late adolescents in high school (M age=16.1), and 111 young adults in college (M age=20.9). Males believed that men had more dominant traits than female participants, and females thought that women had more submissive traits than male participants. Older participants perceived more gender differentiation for these traits than younger participants. Youths believed most strongly in social explanations for differences, followed by biological and religious explanations, although there were age and sex differences in responses. Findings suggest that religious and biological attributions decrease between early adolescence and adulthood for both males and females, but that social attributions increase for females only. Religious attributions were linked to traditional attitudes towards women, social attributions were linked to egalitarian attitudes, while biological attributions were linked to traditional attitudes for males only.     

Human nonindependent mate choice: Is model female attractiveness everything?

Following two decades of research on non-human animals, there has recently been increased interest in human nonindependent mate choice, namely the ways in which choosing women incorporate information about a man's past or present romantic partners ('model females') into their own assessment of the male. Experimental studies using static facial images have generally found that men receive higher desirability ratings from female raters when presented with attractive (compared to unattractive) model females. This phenomenon has a straightforward evolutionary explanation: the fact that female mate value is more dependent on physical attractiveness compared to male mate value. Furthermore, due to assortative mating for attractiveness, men who are paired with attractive women are more likely to be of high mate value themselves. Here, we also examine the possible relevance of model female cues other than attractiveness (personality and behavioral traits) by presenting video recordings of model females to a set of female raters. The results confirm that the model female's attractiveness is the primary cue. Contrary to some earlier findings in the human and nonhuman literature, we found no evidence that female raters prefer partners of slightly older model females. We conclude by suggesting some promising variations on the present experimental design.     

Incorporating geographic distance into mate preference research: Necessities and luxuries, 2.0

This study (N = 370) examined mate preferences in men and women using the budget allocation paradigm across traits typically studied and the value placed on geographic proximity or propinquity. Importantly, traditionally studied preferences (i.e., physical attractiveness and social status) were seen as priorities, whereas the novel trait of distance was a luxury, suggesting that people were willing to travel to find a partner who satisfies their more important mate preferences. Men valued a short‐term mate who was close to them more than women did. Prior work on mate preferences was replicated in their context‐specific nature as per evolutionary models of mate choice.     

Rare male aggression directed toward females in a female‐dominated society: Baiting behavior in the spotted hyena

Spotted hyenas (Crocuta crocuta) are gregarious carnivores. The females are socially dominant to males, and adult males rarely direct aggression toward adult females. This study analyzed all cases in which adult immigrant males behaved aggressively toward adult females in a large population of free‐living hyenas in Kenya, observed for 11 years. Our goals were to describe the conditions under which male attacks on females occur, and address possible adaptive functions. Most aggression directed by adult immigrant males against females occurred when coalitions of two or more males attacked a single adult female, who typically responded by defending herself and fighting back. Male aggression against females frequently occurred at sites of ungulate kills, but males never behaved aggressively toward females over food, and all male attacks on females were unprovoked. Although no mounting or other copulatory behaviors ever occurred during or immediately after an attack, the number of male attacks on females peaked around the time of conception. Daily rates at which males attacked females did not vary with female social rank. However, daily attack rates did vary significantly with female reproductive state, and the highest rates of male attack on females were observed during the two stages of the reproductive cycle during which females were most likely to conceive litters. The adaptive significance of male aggression against females in this species remains unknown, but a tight association between male attacks on females and a female's time of conception provides strong evidence of some role for male aggression in hyena sexual behavior. In particular, our data are consistent with hypotheses suggesting that male aggression toward females in this species either serves to inform females about male fitness or represents sexual harassment. Aggr. Behav. 29:457–474, 2003. © 2003 Wiley‐Liss, Inc.     

Maternal aggression toward infanticidal males of different social status in wild house mice (Mus musculus domesticus)

Maternal aggression was examined in wild female mice (Mus musculus domesticus) derived from animals trapped in Alberta, Canada. Lactating females were tested for their behavior toward intruder males during the time of postpartum estrus while housed in a two-cage apparatus containing a defensible nest area. Prior to being used as intruders, sexually naive males were screened for their behavior toward a newborn pup (83% exhibited infanticide). Only infanticidal males were then housed in pairs and allowed to establish a dominance hierarchy. Dominance status was further verified by a urine marking test. The dominant and subordinate infanticidal males were then placed into a lactating female's cage and observed for 1 hr. The test was terminated immediately when a male began to attack the pups. Lactating females attacked the males in both groups, but subordinate males received more intense attacks than dominant males. Dominant males elicited significantly more fear/defense behavior than subordinate intruders. All of the dominant males and only one submissive male attacked the pups. Females were thus successful in blocking infanticide only by infanticidal subordinate males. Since females do not persist in attacking males with high fighting ability, one function of maternal aggression could be to assess the fighting, and resource holding, potential of a future mate. © 1994 Wiley-Liss, Inc.     

Sex and species recognition by wild male southern white rhinoceros using contact pant calls

Recognition of information from acoustic signals is crucial in many animals, and individuals are under selection pressure to discriminate between the signals of conspecifics and heterospecifics or males and females. Here, we first report that rhinos use information encoded in their calls to assess conspecifics and individuals of closely related species. The southern (Ceratotherium simum) and critically endangered northern (C. cottoni) white rhinos are the most social out of all the rhinoceros species and use a contact call pant. We found that southern white rhino pant calls provide reliable information about the caller’s sex, age class and social situation. Playback experiments on wild territorial southern white rhinoceros males revealed that they responded more strongly to the pant calls of conspecific females compared to the calls of other territorial males. This suggests that pant calls are more important form of communication between males and females than between territorial males. Territorial southern males also discriminated between female and territorial male calls of northern species and reacted more intensively to the calls of northern than southern males. This might be caused by a novelty effect since both species naturally live in allopatry. We conclude that white rhinos can directly benefit from assessing individuals at long distances using vocal cues especially because their eyesight is poor. Pant calls thus likely play a significant role in their social relationships and spatial organization. In addition, better understanding of vocal communication in white rhinos might be helpful in conservation management particularly because of their low reproduction in captivity.