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The present study aimed to explore whether lesbian women's preferences for a sperm donor or a long-term mate show a pattern similar to those of heterosexual women. Three hundred and eighty-three donor insemination patients, of whom 278 were heterosexual and 105 were lesbian, completed a questionnaire comprising a series of 35 traits and rated the importance of each trait in a sperm donor and again in a long term mate. Results showed that traits relating to socioeconomic status, genetic background and general health, physical appearance, and personality were rated by lesbian women as more important in a long-term mate than in a sperm donor. It was further found that both heterosexual and lesbian women attached higher importance to the socioeconomic status, personality and physical appearance of the long-term mate than of the sperm donor; heterosexual women attached similar importance to the genes and health of a long-term mate and a sperm donor, while lesbian women attached greater importance to the genetic background and general health of the sperm donor than those of a long-term mate. The implications and interpretations of the findings are discussed in light of Trivers' parental investment theory. [ABSTRACT FROM AUTHOR]

Introduction: In this study, we investigated the impact of age on mate selection preferences in males and females, and explored how the formation and duration of committed relationships depend on the sex of the person making the selection. Methods: To this end, we utilized data from the television dating shows The Bachelor and The Bachelorette. In these programs, either a single man ("bachelor") or a woman ("bachelorette") has the opportunity to select a potential long-term partner from a pool of candidates. Our analysis encompassed a total of n = 169 seasons from 23 different countries, beginning with the first airing in 2002. Results: We found that the likelihood of the final couple continuing their relationship beyond the broadcast was higher in The Bachelorette than in The Bachelor, although the duration of these relationships was not significantly influenced by the type of show. On average, women were younger, both when selecting their partner and when being chosen. However, men exhibited a greater preference for larger age differences than women. Furthermore, the age of the chosen male partners significantly increased with the age of the "bachelorettes," whereas "bachelors" consistently favored women around 25.5 years old, regardless of their own age. [ABSTRACT FROM AUTHOR]

IntroductionIn this study, we investigated the impact of age on mate selection preferences in males and females, and explored how the formation and duration of committed relationships depend on the sex of the person making the selection.MethodsTo this end, we utilized data from the television dating shows The Bachelor and The Bachelorette. In these programs, either a single man (“bachelor”) or a woman (“bachelorette”) has the opportunity to select a potential long-term partner from a pool of candidates. Our analysis encompassed a total of n = 169 seasons from 23 different countries, beginning with the first airing in 2002.ResultsWe found that the likelihood of the final couple continuing their relationship beyond the broadcast was higher in The Bachelorette than in The Bachelor, although the duration of these relationships was not significantly influenced by the type of show. On average, women were younger, both when selecting their partner and when being chosen. However, men exhibited a greater preference for larger age differences than women. Furthermore, the age of the chosen male partners significantly increased with the age of the “bachelorettes,” whereas “bachelors” consistently favored women around 25.5 years old, regardless of their own age.DiscussionWe discuss these findings within the context of parental investment theory and sexual strategies theory.

The objective of the project was to compare the importance of traits desired in a life partner to traits desired in a sperm donor. A survey was distributed via internet support groups to women undergoing donor insemination and the questionnaire consisted of 35 traits of a desired life partner and of a desired sperm donor. The respondents comprised 278 unmarried childless heterosexual women over 38 years old undergoing donor insemination treatments. The 35 traits of a desired life partner and a desired sperm donor were grouped by confirmatory factor analysis (CFA) into four factors: (i) personality; (ii) physical appearance; (iii) genes and health; and (iv) socio-economic status. Paired-sample t-tests showed that patients attached significantly greater importance to social status, personality, and physical appearance in a desired life partner than to those traits in a desired sperm donor. No differences were found regarding the genetic quality of the desired life partner versus the sperm donor. These findings contribute to the understanding of fertility patients' preferences in sperm donors. [ABSTRACT FROM AUTHOR]

Trust plays a critical role in nearly every aspect of social life. Parental investment theory and social role theory predict that women trust less than men due to a higher sensitivity to risk and betrayal, while men trust more than women to maximize resources and to signal their willingness to lose something. However, the underlying neuropsychological underpinnings for this gender difference are still obscure. In this study, we used functional magnetic resonance imaging (fMRI) to investigate the neural signatures of gender differences in trust by simultaneously scanning 11 male and 11 female same-gender, fixed dyads who played a multi-round binary trust game with varying levels of payoff (low/moderate/high) as an indicator of social risk. Our results showed that men trusted more than women and payoff level moderated the effect of gender on trust. While men trusted the same at all payoff levels, women trusted less with higher payoff levels. This pattern was supported by our neuroimaging finding: men showed a higher activation in the left inferior frontal gyrus (ventrolateral prefrontal cortex) and right precuneus than women, indicating that men exert more effort to inhibit the information of payoff levels and to use self-referencing to infer the strategies of partners with the goal of maximizing profit. Furthermore, men showed equivalent activation in the subgenual anterior cingulate cortex across payoff levels, whereas women showed a decreased activation with increasing payoff level – indicating decreased group bonding with higher risk in women. In conclusion, our results imply that women are more sensitive to social risk while trusting, which has implications for financial interactions, interpersonal relationships, and social involvement.

Trust plays a critical role in nearly every aspect of social life. Parental investment theory and social role theory predict that women trust less than men due to a higher sensitivity to risk and betrayal, while men trust more than women to maximize resources and to signal their willingness to lose something. However, the underlying neuropsychological underpinnings for this gender difference are still obscure. In this study, we used functional magnetic resonance imaging (fMRI) to investigate the neural signatures of gender differences in trust by simultaneously scanning 11 male and 11 female same-gender, fixed dyads who played a multi-round binary trust game with varying levels of payoff (low/moderate/high) as an indicator of social risk. Our results showed that men trusted more than women and payoff level moderated the effect of gender on trust. While men trusted the same at all payoff levels, women trusted less with higher payoff levels. This pattern was supported by our neuroimaging finding: men showed a higher activation in the left inferior frontal gyrus (ventrolateral prefrontal cortex) and right precuneus than women, indicating that men exert more effort to inhibit the information of payoff levels and to use self-referencing to infer the strategies of partners with the goal of maximizing profit. Furthermore, men showed equivalent activation in the subgenual anterior cingulate cortex across payoff levels, whereas women showed a decreased activation with increasing payoff level – indicating decreased group bonding with higher risk in women. In conclusion, our results imply that women are more sensitive to social risk while trusting, which has implications for financial interactions, interpersonal relationships, and social involvement. [ABSTRACT FROM AUTHOR]

Why do perceivers categorize and stereotype others by their biological sex and age? We suggest that perceivers do so because sex and age interactively shape adaptive goals (e.g., mating, parenting) and strategies. And because such goals and strategies pose different fitness-relevant opportunities and threats, social perceivers use others' sex-age as a cue for predicting others' behaviors. This perspective has multiple implications, which we test in a range of U.S. undergraduate and online survey samples. First, we find that perceivers categorize others not by sex and age independently, but by the interaction of their sex and age (i.e., people mentally group others as females and males of specific ages) (Studies 1 and 2). Second, perceivers hold stereotypes of men and women of specific ages as being differentially oriented towards short- and long-term mating as well as parenting goals (e.g., women are stereotyped to be more oriented towards long-term mating goals than men are, but only at younger ages) (Studies 3 and 4). Finally, providing perceivers with direct information about others' adaptive goals can influence the extent to which perceivers apply stereotypes of agency, communion, and competence, and can even override typical sex stereotypes (e.g., men are generally stereotyped to be more agentic than women, but this sex stereotype disappears when both men and women are presented as engaging in short-term mating goals) (Studies 5 and 6). The current findings challenge existing thinking about sex and age stereotyping, and demonstrate the value of an adaptationist approach for thinking about social perception and stereotypes. [ABSTRACT FROM AUTHOR]

While social mate choice is an obvious point where sexual selection acts on males, cryptic selection can occur based on how much females invest in a male's offspring. I tested 4 hypotheses about the relationship between female investment and social mate attractiveness by manipulating a sexually selected trait, white tail feathers ("tail white"), in male Dark-eyed Juncos (Junco hyemalis thurberi): (1) the differential allocation hypothesis predicts that females optimize lifetime reproductive success by maximizing parental investment in the offspring of ornamented mates and minimizing investment when mated to less attractive males; (2) instead of positive differential allocation, females could show negative differential allocation by investing more in less attractive males to compensate for their lower quality; (3) female care could also be influenced directly by paternal investment, in particular what appears to be positive differential allocation could be compensation for reduced care by attractive males; or (4) females could reduce care when paired with socially attractive males that are "good parents". To evaluate these hypotheses, I examined the impact of tail white manipulation on clutch size, female incubation and brooding, and female and male provisioning. Females did not differentially allocate in relation to social mate attractiveness, nor were females responsive to patterns of male investment, even although artificially attractive males provisioned offspring significantly more than did controls. Naturally bright males, who were also the largest males, did not provision at higher rates, highlighting the need to experimentally separate the role of specific traits from other correlated factors. Tail white-manipulated males were involved in rare cases of polygyny and at times were actively guarded by their mates. Together, these results suggest that tail white influences reproductive behaviors in this junco population, but because of the potential for extrapair paternity, additional data are needed to accurately investigate the trait's role in female investment. [ABSTRACT FROM AUTHOR]

Benevolent sexism (BS) has detrimental effects on women, yet women prefer men with BS attitudes over those without. The predominant explanation for this paradox is that women respond to the superficially positive appearance of BS without being aware of its subtly harmful effects. We propose an alternative explanation drawn from evolutionary and sociocultural theories on mate preferences: Women find BS men attractive because BS attitudes and behaviors signal that a man is willing to invest. Five studies showed that women prefer men with BS attitudes (Studies 1a, 1b, and 3) and behaviors (Studies 2a and 2b), especially in mating contexts, because BS mates are perceived as willing to invest (protect, provide, and commit). Women preferred BS men despite also perceiving them as patronizing and undermining. These findings extend understanding of women's motives for endorsing BS and suggest that women prefer BS men despite having awareness of the harmful consequences. [ABSTRACT FROM AUTHOR]

This special section contains a collection of articles that study how children are affected by their sibship size and composition by examining their influence on several demographic outcomes across time and space. The importance of the specific historical context, as put forward by the conditional or gendered resource dilution model, seems to be justified, as inheritance practices and gender preferences were determining demographic outcomes.While these studies provide us with the possibility of reflecting on what kinds of pathways/mechanisms are behind sibling effects, they also demonstrate that much more can and should be investigated.Four recommendations for future studies are formulated: (1) future studies should continue on the same path as the articles in this special section and address different outcomes in a variety of contexts to determine under which conditions siblings matter for life transitions and demographic outcomes; (2) theoretical frameworks from different disciplines should be integrated to increase knowledge exchange; (3) researchers should think more about, and be transparent about, how siblings and families are defined; and (4) qualitative studies should be included to a greater extent, since quantitative studies alone cannot answer the questions we have about how and why sibling effects influence life transations and outcomes. [ABSTRACT FROM AUTHOR]

Parental investment hypotheses regarding mate selection suggest that human males should seek partners featured by youth and high fertility. However, females should be more sensitive to resources that can be invested on themselves and their offspring. Previous studies indicate that economic status is indeed important in male attractiveness. However, no previous study has quantified and compared the impact of equivalent resources on male and female attractiveness. Annual salary is a direct way to evaluate economic status. Here, we combined images of male and female body shape with information on annual salary to elucidate the influence of economic status on the attractiveness ratings by opposite sex raters in American, Chinese and European populations. We found that ratings of attractiveness were around 1000 times more sensitive to salary for females rating males, compared to males rating females. These results indicate that higher economic status can offset lower physical attractiveness in men much more easily than in women. Neither raters' BMI nor age influenced this effect for females rating male attractiveness. This difference explains many features of human mating behavior and may pose a barrier for male engagement in low-consumption lifestyles. [ABSTRACT FROM AUTHOR]

Music is a human universal, which suggests a biological adaptation. Several evolutionary explanations have been proposed, covering the entire spectrum of natural, sexual, and group selection. Here we consider the hypothesis that musical behaviour constitutes a reliable or even costly signal of fitness, and thus may have evolved as a human trait through sexual selection. We experimentally tested how musical performance quality (MPQ), in improvisations on the drums, saxophone, and violin, affects mate values and mate preferences perceived by a prospective partner. Swedish student participants (27 of each sex) saw a face of a person of the opposite sex and heard a piece of improvised music being played. The music occurred in three levels of MPQ and the faces in three levels of facial attractiveness (FA). For each parametric combination of MPG and FA, the participants rated four mate value scales (intelligence, health, social status, and parenting skill) and four mate preference scales (date, intercourse, and short- and long term relationship). Consistent with sexual selection theory, mate value ratings were generally increased by MPQ for raters of both sexes. Consistent with more specific hypotheses that follow from combining sexual selection and parental investment theory, women’s but not men’s preference for a long-term, but not short-term, relationship was significantly increased by MPQ, MPQ generally affected women’s ratings more than men’s, FA generally affected men’s ratings more than women’s, and women’s ratings of intelligence were even more influenced by MPQ than by FA. [ABSTRACT FROM AUTHOR]

When serious romantic relationships are terminated, partners are faced with convoluted and complex challenges of detachment from their previous partner, negative feelings about the overall situation, and the need to move forward in life. When faced with this relational upheaval, some individuals employ and find relief in superficial or noncommittal rebound relationships, which act as a means for coping with the loss of the previous relationship and the severed emotional attachment to an ex-partner, but which are under studied by empirical researchers. In a study of 201 participants, men were predicted and found to be more likely to enter rebound relationships in the aftermath of a relational termination based on lower levels of social support, more emotional attachment to an ex-partner, and displaying the ludus (or game playing) love style. In addition to the measures of these variables, gender socialization and parental investment theory provide further support for the study’s claims. In sum, rebound relationships were employed by men as a distraction from their feelings of emotional attachment for their ex-partner, but also as a source of support and due to inherent ludic characteristics.

Parents face trade-offs between investing in child health and other fitness enhancing activities. In humans, parental investment theory has mostly been examined through the analysis of differential child outcomes, with less emphasis on the actions parents take to further a particular offspring’s condition. Here, we make use of household data on health-seeking for children in a high mortality context where such behaviours are crucial for offspring survival. Using Demographic and Health Survey (DHS) data from 17 sub-Saharan African countries, we examine whether maternal factors (age, health, marital status) and child factors (birth order, health, sex, age) independently influence parental investment in health-seeking behaviours: two preventative behaviours (malaria net use and immunization) and two curative ones (treating fever and diarrhoea). Results indicate that children with lower birth order, older mothers and mothers with better health status have higher odds of investment. The effects of a child’s sex and health status and whether the mother is polygynously married vary depending on the type of health-seeking behaviour (preventative versus curative). We discuss how these results square with predictions from parental investment theory pertaining to the state of mothers and children, and reflect on some potential mechanisms and directions for future research.

The pattern of increased nest defense effort over the course of a nesting season could result from three distinct (albeit non-exclusive) mechanisms: increased value of offspring to parents with progression toward independence (parental investment theory), decreased opportunity for renesting (renesting potential hypothesis), or decreased perceived costs of defense after repeated encounters with human observers (positive reinforcement hypothesis). To gauge relative empirical support for each of these mechanisms, we disentangle these three often-confounded hypotheses using multimodel inference with mixed-model ordinal regression applied to an extensive red-winged blackbird ( Agelaius phoeniceus) nesting data set (4518 monitoring visits to 1330 nests). Parent aggression was rated on an ordinal scale (0-4) during repeated monitoring visits. Additionally, we assessed clutch/brood size, nest density, time of day, and nest concealment effects on aggression. In a preliminary analysis, including all three major hypotheses, male and female nest defense was most strongly explained by parental investment (nest age). Positive reinforcement (visit number) and renesting potential (Julian date) were also well-supported predictors in males. The interactions of decomposed nest age (within-individual and between-individual centered) with Julian date were particularly important in the top male model. Additional factors, such as clutch/brood size, nest density, and nest concealment, appeared to have larger predictive roles in explaining female aggression relative to males. These patterns are likely explained by different sexual reproductive roles within a polygynous mating system. Our study highlights the importance of interacting mechanisms involving parental investment theory and the use of within-individual standardization to help disentangle competing and empirically confounded hypotheses. Significance statement: Avian nest defense generally increases over the course of a nesting season, potentially from the result of three different mechanisms: parental investment theory, renesting potential hypothesis, or positive reinforcement hypothesis from repeated nest visitation. We revisit this classic question through a comprehensive analytical approach with an extensive observational data set with red-winged blackbirds, employing multimodel selection and within-individual and between-individual centering techniques. We found that parental investment (nest age) was the strongest predictor of nest defense for both sexes; however, positive reinforcement and renesting potential also appeared to help explain additional variation in nest defense for males. Competitiveness of models with interactive effects indicated that these mechanisms do not operate independently for either sex, and additional covariates (e.g., clutch/brood size) especially aided female model competiveness. Our study highlights the importance of multiple and often interacting factors that influence avian nest defense. [ABSTRACT FROM AUTHOR]

Birds exhibit various forms of anti-predator behaviours to avoid reproductive failure, with mobbing-observation, approach and usually harassment of a predator-being one of the most commonly observed. Here, we investigate patterns of temporal variation in the mobbing response exhibited by a precocial species, the northern lapwing ( Vanellus vanellus). We test whether brood age and self-reliance, or the perceived risk posed by various predators, affect mobbing response of lapwings. We quantified aggressive interactions between lapwings and their natural avian predators and used generalized additive models to test how timing and predator species identity are related to the mobbing response of lapwings. Lapwings diversified mobbing response within the breeding season and depending on predator species. Raven Corvus corax, hooded crow Corvus cornix and harriers evoked the strongest response, while common buzzard Buteo buteo, white stork Ciconia ciconia, black-headed gull Chroicocephalus ridibundus and rook Corvus frugilegus were less frequently attacked. Lapwings increased their mobbing response against raven, common buzzard, white stork and rook throughout the breeding season, while defence against hooded crow, harriers and black-headed gull did not exhibit clear temporal patterns. Mobbing behaviour of lapwings apparently constitutes a flexible anti-predator strategy. The anti-predator response depends on predator species, which may suggest that lapwings distinguish between predator types and match mobbing response to the perceived hazard at different stages of the breeding cycle. We conclude that a single species may exhibit various patterns of temporal variation in anti-predator defence, which may correspond with various hypotheses derived from parental investment theory. [ABSTRACT FROM AUTHOR]

Bjorklund and Kipp (1996) provide an evolutionary framework predicting that there is a female advantage in inhibition and self-regulation due to differing selection pressures placed on males and females. The majority of the present review will summarize sex differences in self-regulation at the behavioral level. The neural and hormonal underpinnings of this potential sexual dimorphism will also be investigated and the results of the experiments summarized will be related to the hypothesis advanced by Bjorklund and Kipp (1996). Paradoxically, sex differences in self-regulation are more consistently reported in children prior to the onset of puberty. In adult cohorts, the results of studies examining sex differences in self-regulation are mixed. A few recent experiments suggesting that females are less impulsive than males only during fertile stages of the menstrual cycle will be reviewed. A brief discussion of an evolutionary framework proposing that it is adaptive for females to employ a self-regulatory behavioral strategy when fertile will follow.

Personal ads have long served as a potentially rich source of information for social scientists regarding what women and men appear to be looking for in a partner and what they believe potential partners are looking for in them. Almost every study of this type has content analyzed existing personal ads in print media or, more recently, on the Internet. Many of the limits of this research approach were addressed in a study by Strassberg and Holty (2003) utilizing an experimental research design. Contrary to theory, prior research, and prediction, the most popular female seeking male (FSM) ad in that study was one in which the woman described herself as "financially independent, successful [and] ambitious," producing over 50 % more responses than the next most popular ad, describing the writer as "very attractive and slim." The present study replicated the Strassberg and Holty methodology, placing the same fictitious MSF and FSM personal ads using far more accessible Internet personal ad sites. Contrary to the previous finding, but consistent with evolutionary theories and social psychological experiments (e.g., Townsend & Wasserman, 1998), ads that presented the woman as attractive and the man as financially successful elicited the most interest. [ABSTRACT FROM AUTHOR]

Bjorklund and Kipp (1996) provide an evolutionary framework predicting that there is a female advantage in inhibition and self-regulation due to differing selection pressures placed on males and females. The majority of the present review will summarize sex differences in self-regulation at the behavioral level. The neural and hormonal underpinnings of this potential sexual dimorphism will also be investigated and the results of the experiments summarized will be related to the hypothesis advanced by Bjorklund and Kipp (1996). Paradoxically, sex differences in self-regulation are more consistently reported in children prior to the onset of puberty. In adult cohorts, the results of studies examining sex differences in self-regulation are mixed. A few recent experiments suggesting that females are less impulsive than males only during fertile stages of the menstrual cycle will be reviewed. A brief discussion of an evolutionary framework proposing that it is adaptive for females to employ a self-regulatory behavioral strategy when fertile will follow. [ABSTRACT FROM AUTHOR]

Regret and anticipated regret enhance decision quality by helping people avoid making and repeating mistakes. Some of people's most intense regrets concern sexual decisions. We hypothesized evolved sex differences in women's and men's experiences of sexual regret. Because of women's higher obligatory costs of reproduction throughout evolutionary history, we hypothesized that sexual actions, particularly those involving casual sex, would be regretted more intensely by women than by men. In contrast, because missed sexual opportunities historically carried higher reproductive fitness costs for men than for women, we hypothesized that poorly chosen sexual inactions would be regretted more by men than by women. Across three studies ( Ns = 200, 395, and 24,230), we tested these hypotheses using free responses, written scenarios, detailed checklists, and Internet sampling to achieve participant diversity, including diversity in sexual orientation. Across all data sources, results supported predicted psychological sex differences and these differences were localized in casual sex contexts. These findings are consistent with the notion that the psychology of sexual regret was shaped by recurrent sex differences in selection pressures operating over deep time. [ABSTRACT FROM AUTHOR]

Parental investment theory and sexual strategies theory predict that women and men should differ on many of the criteria by which they choose mates. These theories posit a gender selectivity effect, such that women should be more selective than men in their mating choices. The theories also posit an age differential effect, such that women should seek older mates, and men should seek younger mates. These two hypotheses have been supported by self-report surveys, speed-dating studies, analysis of on-line and newspaper personal ads, and laboratory analog studies. However, each of these data sources has limitations. Therefore, a new source of data may provide a valuable additional test of the robustness of these effects. The current study examined two independent sources of data involving blind dates arranged and paid for by newspapers. Consistent with the first hypothesis, we found women to be more selective than men. We also found that matchmakers tended to pair older men with younger women, consistent with the second hypothesis. However, contrary to the second hypothesis, we found no evidence that the age differential between members of a couple influenced their ratings of the date. The implications of these findings are discussed. [ABSTRACT FROM AUTHOR]

Egg composition varies both within and between clutches, and mothers are expected to alter their deposition of resources to the egg depending on environmental conditions and breeding strategies. Within-clutch variation in egg composition has been proposed to reflect an adaptive maternal strategy influencing sibling competition. In species with brood reduction, mothers should reinforce brood hierarchies due to hatching asynchrony and favour senior chicks by making first-laid eggs larger, richer in nutrients, with higher testosterone and carotenoid levels and lower corticosterone concentrations than last-laid eggs [parental favouritism hypothesis (PFH)]. Moreover, mothers that are of better quality and/or experience better feeding conditions during laying are expected to increase their deposition of resources to the egg, resulting in differences between clutches [investment hypothesis (IH)]. Several components may act together to provide an optimal reproductive strategy, but studies of variation in different egg components in the same egg are relatively rare. We analysed egg size, testosterone and corticosterone concentrations and carotenoids measured as yolk colour between and within clutches for the facultative siblicidal Black-legged Kittiwake Rissa tridactyla. First-laid eggs were larger, contained lower testosterone, higher yolk colour score, and similar corticosterone levels than last-laid eggs. Thus, only differences in egg size and yolk colour supported the PFH. We used within-clutch egg size dimorphism as an indicator of the quality of the mother or the feeding conditions during laying. In support of the IH, we found that mothers of better quality or that experienced better feeding conditions deposited more corticosterone into their eggs. High corticosterone levels may benefit nestlings when there is no brood reduction but high sibling competition is present. We found no support for the hypothesis that egg components are mutually adjusted to each other and we discuss the possible reasons for this. [ABSTRACT FROM AUTHOR]

Guided by Relational Framing and Parental Investment Theories, this investigation examined experimentally induced flirtatious interactions. United States undergraduates ( N = 252) from the Mid-Atlantic region viewed a flirtatious interaction and rated a confederate on physical and social attraction, affiliation, dominance, and conversational effectiveness. Generally, it was hypothesized that different flirting motivations would lead to different evaluations of the flirters, and perceptions of flirters would vary based on gender. Results revealed that men were evaluated as more dominant and affiliative than women when flirting, but dominance in men was not perceived as attractive or conversationally effective. In addition, men's attraction to women increased significantly when women flirted for sexual motives, and women's attraction to men decreased significantly when men flirted for fun. Overall, the results provide mixed support for both theories. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate whether the mate-choice preferences predicted by the most common theories of the evolution of heterosexual (i.e., the Theory of Parental Investment; Trivers, 1972) and homosexual mating behavior (i.e., the Alliance Formation Hypothesis; Muscarella, 2000) are present in a sample of Romanian men. According to these hypotheses, heterosexual men should prefer younger partners, as they have a higher reproductive value, while homosexual men are expected to prefer older partners, as they seek social allies, and older men can offer more resources. These hypotheses were tested on a sample of same-age Romanian men, by performing a content analysis of online personal advertisements (N=53 homosexual men, mean age = 29.25 years, SD=8.45, and N = 59 heterosexual men, mean age = 31.10 years, SD=8.72). The results were mostly consistent with the above-mentioned theories. Romanian heterosexual men sought female partners who were significantly younger than themselves, and physically attractive. Romanian homosexual men preferred male partners who were significantly older than themselves, but they did not emphasize socio-emotional attributes more than the attributes related to physical attractiveness. Theoretical and practical implications of the results are discussed. Further studies are needed that rely on large representative samples. [ABSTRACT FROM AUTHOR]

We predicted that the proportion of suckling attempts rejected and terminated by the mother would be greater for female foals than male foals, based on parent offspring conflict theory and on the assumption that throughout the study, all zebra mothers were in good condition because of captivity. We presumed that an increasing rate of suckling ter- minated or rejected by a mother would indicate a decreasing effort by the mother to invest in her offspring. We observed foals of captive plains zebras at the Dvůr Králové Zoo, Czech Republic. We found that the probability of successful suckling tended (slope = 0.0016; Z = 1.78; P = 0.074) to increase with increasing age of the female foals, but decreased (slope = -0.0018; Z = -2.51; P = 0.012) with increasing age of the male foals. The proportion of suckling bouts terminated by the mother decreased (slope = -0.0077; Z = -4.27; P < 0.0001) with increasing age of the female foals, but not the male foals (slope = -0.0005; Z = -0.34; P = 0.732). Our results indicate that conflict between mothers and female foals was less than that between mothers and male foals. The observed sex differences in termination and rejection of suckling bouts could be explained by the different behavior of the male and female foals, or by the selective maternal investment. Finally, we revealed no significant effect of herdmates on suckling behavior. [ABSTRACT FROM AUTHOR]

Abstract: An evolutionary psychological perspective has much to offer the study of Internet behavior. However, cyber-psychologists have hitherto neglected this rich theoretical tradition and evolutionary psychologists have been slow to apply their perspective to computer-mediated behavior. This paper applies an evolutionary perspective to the study of Internet behavior in four relevant domains: (1) mating and sexual competition, (2) parenting and kinship, (3) trust and social exchange, and (4) personal information management. Both general and specific evolutionary theories are explored in relation to online behavior in each domain, with an emphasis on generating testable hypotheses for future research. [Copyright &y& Elsevier]

The attention of evolutionary psychologists studying the mate-choice processes in humans has recently started to be oriented not only towards single individuals, but also towards individuals that are already involved in stable relationships. The aim of our study was to include the variable marital status (i.e., single versus attached individuals) in the analysis of mate-choice strategies of Romanian individuals, as reflected by the personal advertisements market. We performed content analysis of 400 personal advertisements (100 ads places by single men, 100 ads places by attached men, 100 ads placed by single women, and 100 ads placed by attached women). Several categories of attributes with mate-choice evolutionary significance were quantified, such as: physical, material, educational and emotional attributes. Single Romanian men listed a significantly higher number of emotional attributes to describe themselves than the attached men. Compared to the single women, attached women used a significantly higher number of self-descriptive attributes. Single men requested a higher number of emotional and educational attributes from their sought partners. Attached women requested a significantly higher number of physical, educational and material attributes from their sought partners than the single women. These results are discussed in relation to several paradigms from evolutionary psychology and to the findings of a previous study of the Romanian mate-choice market. [ABSTRACT FROM AUTHOR]

The authors investigated sex differences in human risk sensitivity by using a computerized choice task with an energy budget analogue. In addition, they explored possible personality predictors of variance sensitivity. The authors modified the traditional energy budget model from those used in risk-sensitive foraging research with nonhuman animals for appropriate use with a human population. Participants chose between 2 computer icons, 1 yielding a fixed-point reward and the other offering variable points. Men were risk prone in the negative budget and risk averse in the positive budget. Women were risk averse in the negative budget. Personality was not predictive of risk-sensitive bias. Interpreting the results using an evolutionary model, the authors found support for a biological and environmental construct of risk-sensitive behavior. [ABSTRACT FROM AUTHOR]

We examined sex differences in the prevalence, incidence, reasons for, and consequences of infidelity. Participants (Study 1, 543 undergraduates in the Northwestern US; Study 2, 313 undergraduates and 233 community members in the Mid-Atlantic US), reported on infidelity by questionnaire. Using a broad definition of cheating, women reported being as unfaithful or more unfaithful than men. Men were more suspicious about cheating and more likely to discover the cheating than women. Women were more likely to break up with their partners, to begin new relationships after cheating, and to report reasons for cheating that may indicate a desire to switch long-term mates, such as being unhappy in the current relationship. Results are discussed in the context of evolutionary theory. [ABSTRACT FROM AUTHOR]

This study explores the impact of photographs and self-descriptions on success in attracting dates in single and divorced heterosexual clients (n = 589) of a large commercial dating service (Great Expectations Inc.) in Los Angeles. Predictions and a rationale for the outcome are based on Parental Investment Theory (Trivers, 1972). Findings indicate that attractiveness ratings of photographs of clients consistently explain variance in success in attracting dates, with the most attractive women and men being selected most often. There is one exception to this: among men who want children the most attractive ones are not selected most frequently. Aspects of self-descriptions (financial and non-financial resources, altruism, physical health, hedonistic tendencies, and social desirable qualities) extracted from the clients' profiles do not predict significant variance in dating success. Overall the results do not provide support for the role of Parental Investment Theory (Trivers, 1972) in dating mediated by the agency in our study. Discussion focuses on alternative paradigms, methodological issues, and implications for the further development of a theory of mediated dating. [ABSTRACT FROM AUTHOR]

Evolutionary psychologists generally combine sexual selection theory and empirical research to identify mating strategies in humans. The theory behind the current literature on human mating is the theory of parental investment (Trivers, 1972), which states that during mate search, given the asymmetry in parental investment of the two sexes, females should focus on attributes reflecting resources, whereas males should focus on indicators of health and fertility. Our study is an investigation of mating strategies reflected by the Romanian market of personal advertisements. We performed the content analysis of 400 personal advertisements placed online by heterosexual Romanian advertisers. Our findings are in agreement with Trivers's predictions and with other similar studies. Thus, Romanian men offered resources and were more interested in younger partners and in attributes signaling health and fertility. Romanian women were significantly more interested than men in older partners and in attributes reflecting wealth of the sought partners. Romanian women appear to be well attuned to their market value, whereas men overestimate themselves. Our study is, to our knowledge, the first one to investigate the Romanian advertisements market from an evolutionary psychological perspective, with a potential impact on the cognitive-behavioral therapy of couples and families. [ABSTRACT FROM AUTHOR]

A number of evolutionary theories of human life history assume a quantity-quality tradeoff for offspring production: parents with fewer offspring can have higher biological fitness than those with more. Direct evidence for such a tradeoff, however, is mixed. We tested this assumption in a community of Ecuadorian Shuar hunter-horticulturists, using child anthropometry as a proxy for fitness. We measured the impact of household consumer/producer (CP) ratio on height, weight, skinfold thicknesses, and arm and calf circumferences of 85 children and young adults. To control for possible ‘phenotypic’ correlates that might mask the effect of CF ratio on anthropometry, we also measured household garden productivity, wealth, and social status. Regression models of the age-standardized variables indicated a significant negative impact of CF ratio on child growth and nutrition. The age-standardized height and weight of children in households with the largest CF ratio (10) were 1.38 and 1.44 standard deviations, respectively, below those of children in households with the smallest CF ratio (2). Surprisingly, garden productivity, wealth, and status had little to no effect on the fitness proxies. There was, however, an interesting and unexpected interaction between status and sex: for females, but not males, higher father status correlated significantly with higher values on the proxies. [ABSTRACT FROM AUTHOR]

A survey study examining the relative importance of various social and physical traits in heterosexual attraction was conducted. Data from 198 male and female heterosexual college students revealed that women ranked body odor as more important for attraction than “looks” or any social factor except “pleasantness.” Moreover, in contrast to response to fragrance use, liking someone''s natural body odor was the most influential olfactory variable for sexual interest for both men and women. Men rated a woman''s good looks as most desirable and as more important than any other factor except pleasantness. Sex differences in the relative ranking of several social factors were consistent with prior research. [Copyright &y& Elsevier]

The transition to grandparenthood, that is the birth of the first grandchild, is often assumed to increase the subjective well-being of older adults; however, prior studies are scarce and have provided mixed results. Investigation of the associations between grandparenthood and subjective well-being, measured by self-rated life satisfaction, quality of life scores, and depressive symptoms, used the longitudinal Survey of Health, Ageing and Retirement in Europe from 13 countries, including follow-up waves between 2006 and 2015 ( n = 64,940 person-observations from 38,456 unique persons of whom 18,207 had two or more measurement times). Both between-person and within-person (or fixed-effect) regression models were executed, where between-person associations represent results across individuals, that is, between grandparents and non-grandparents; within-person associations represent an individual's variation over time, that is, they consider whether the transition to grandparenthood increases or decreases subjective well-being. According to the between-person models, both grandmothers and grandfathers reported higher rate of life satisfaction and quality of life than non-grandparents. Moreover, grandmothers reported fewer depressive symptoms than women without grandchildren. The within-person models indicated that entry into grandmotherhood was associated with both improved quality of life scores and improved life satisfaction. These findings are discussed with reference to inclusive fitness theory, parental investment theory, and the grandmother hypothesis.

Sexual responses are thought to be controlled by a brain module called the sexual module. Sexual strategies of males and females vary to a great extent, and sexual responses of males and females may be affected by their sexual strategies. However, the current view of the sexual module is that of a unisex module. This might be questionable since brain modules are defined as evolved cognitive mechanisms to solve adaptive problems which are different for males and females. We hypothesize that the sexual module responds differently in the presence of complex (high-order) contextual cues that are related to gender-dimorphic sexual strategies in males and females.We conducted a priming experiment in which stimuli related to sexual strategies were disentangled from their sexual meaning. Nonsexual priming pictures related to either economic resources or social interactions preceded a sexual-target picture in order to test whether the primes were able to modulate the subjective sexual response to the sexual target. In a control condition, priming pictures without relation to mating preferences but with similar emotional impact were presented. In males, sexual responses were similar in the experimental and control conditions. In females, however, primes related to economic resources or social interactions modulated sexual arousal significantly more than the control primes. Our findings suggest that brain modules dedicated to process the experimental primes were functionally connected with the sexual module in females more than in males, making females’ sexual responses more prone to the impact of high-order cultural cues than males’ sexual responses. A gender-dimorphic connectivity of the sexual module may be the way in which gender-dimorphic sexual strategies are implemented in the human mind. [ABSTRACT FROM AUTHOR]