Human reproductive behavior, life history, and the Challenge Hypothesis: A 30-year review, retrospective and future directions.

The Challenge Hypothesis (Wingfield et al., 1990) originally focused on adult male avian testosterone elevated in response to same-sex competition in reproductive contexts. The purpose of the present paper is to demonstrate how the Challenge Hypothesis has shaped ideas about human life histories. We conduct a citation analysis, drawing upon 400 Google Scholar citations in the human literature to identify patterns in this body of scholarship. We cover key factors, such as context and personality traits, that help explain variable testosterone responses such as winning/losing to adult competitive behavior. Findings from studies on courtship and sexual behavior indicate some variation in testosterone responses depending on factors such as motivation. A large body of research indicates that male testosterone levels are often lower in contexts of long-term committed partnerships and nurturant fathering and aligned with variation in male mating and parenting effort. As the Challenge Hypothesis is extended across the life course, DHEA and androstenedione (rather than testosterone) appear more responsive to juvenile male competitive behavior, and during reproductive senescence, baseline male testosterone levels decrease just as male life history allocations show decreased mating effort. We discuss how research on testosterone administration, particularly in older men, provides causal insight into effects of testosterone in humans, and how this "natural experiment" can be viewed in light of the Challenge Hypothesis. We synthesize central concepts and findings, such as an expanded array of costs of testosterone that inform life history tradeoffs between maintenance and reproductive effort, and we conclude with directions for future research.

Salivary aldosterone and cortisone respond differently to high- and low-psychologically stressful soccer competitions.

Aldosterone and cortisone are released in response to physical and psychological stress. However, aldosterone and cortisone responses in children engaged in physical competition have not been described. We examined salivary aldosterone and salivary cortisone responses among Hong Kongese boys, aged 8-11 years, during (1) a soccer match against unknown competitors (N = 84, high psychological stress condition) and (2) an intrasquad soccer scrimmage against teammates (N = 81, low psychological stress condition). Aldosterone levels increased during the soccer match and intrasquad soccer scrimmage conditions, consistent with the view that aldosterone responds to physical stress. During the soccer match, winning competitors experienced larger increases in aldosterone compared to losing competitors, indicating that the degree of aldosterone increase was attenuated by match outcome. Cortisone increased during the soccer match and decreased during the intrasquad soccer scrimmage. Competitors on teams that resulted in a tie had larger cortisone increases compared to winners or losers. These findings highlight that the degree of cortisone change is related to boy's cognitive appraisal of the competitor type (i.e., teammates vs. unknown competitors) and the competitive nature of the game (e.g., tie). These results shed new light on adrenal hormone mediators of stress and competition during middle childhood.

Salivary steroid hormone responses to dyadic table tennis competitions among Hong Kongese juvenile boys.

OBJECTIVES: Little is known about salivary steroid hormone responses to dyadic competition among prepubescent boys. The current study explored pre-match and post-match testosterone, dehydroepiandrosterone (DHEA), androstenedione, and cortisol among 22 ethnically Chinese, Hong Kongese table tennis athletes, aged 8-11 years, during dyadic competition against peers. These data provide novel comparative insight into boys' hormone responses when participating in similar forms of competition to that of adults. METHODS: Measures of salivary steroid hormones, age, outcome, and participant's self-reported perceived performance were obtained. Pre-match salivary steroid hormones and competition-induced steroid hormone changes were explored to further assess overall hypothalamic-pituitary-adrenal axis activity. RESULTS: Cortisol decreased for most participants, whereas testosterone measures were below the sensitivity of the assay. DHEA and androstenedione did not significantly change during the table tennis exhibitions and were unrelated to independent performance variables. Correlational analyses indicated that competition-induced androstenedione and cortisol change were positively related. CONCLUSIONS: Findings show that juvenile boys' steroid hormone responses during dyadic athletic competition differ in comparison to adult males, in whom cortisol and testosterone tend to rise. Lack of significant DHEA and androstenedione change during the table tennis competition differs from our previous work that showed DHEA and androstenedione were sensitive to more physically taxing forms of athletic competition (eg, soccer). These results are discussed in light of potential factors that may have contributed to these differences.

Patterns and predictors of depressive symptoms among Jamaican fathers of newborns.

BACKGROUND: Approximately 10% of fathers in the Cultural West (i.e., US, Europe, and Australia) experience depression. We broaden the cultural scope of paternal depression research by investigating the prevalence and predictors of depressive symptoms among Jamaican fathers. METHODS: The present research draws upon structured interviews with 3425 fathers of newborn children participating in a Jamaican birth cohort study-JA Kids-and represents one of the largest sample sizes of any study on postnatal depression among fathers worldwide. This sample of fathers participated from July to September 2011, and represents approximately 30% of all men who became fathers during that time in Jamaica. Fathers answered questions about sociodemographic background, relationship status and quality, social support, health, expectations and views of a partner's pregnancy, and the ten-item Edinburgh Postnatal Depression Scale (EPDS). RESULTS: Analyses reveal that 9.1% (95% CI 8.1-10.1) of these Jamaican fathers of newborns had EPDS scores of 10 or higher, indicative of possible depression. Results suggest that educational attainment was not related to EPDS scores, though higher indices of material wealth (e.g., refrigerator and vehicle) were weakly, negatively related to EDS scores. Paternal age was also weakly negatively predictive of EDS scores. Whereas relationship status was unrelated to depressive symptoms, relationship quality negatively predicted depressive symptoms. Several other measures of social support (lacking a close circle of friends, fewer family, or friends to help in times of trouble) were also associated with higher EPDS scores. CONCLUSIONS: We interpret these findings in light of existing work on paternal depression, including the importance of social context and support.

A review of human male field studies of hormones and behavioral reproductive effort.

The purpose of this paper is to review field studies of human male hormones and reproductive behavior. We first discuss life history theory and related conceptual considerations. As illustrations, distinctive features of human male life histories such as coalitional aggression, long-term partnering and paternal care are noted, along with their relevance to overall reproductive effort and developmental plasticity. We address broad questions about what constitutes a human male field study of hormones and behavior, including the kinds of hormone and behavioral measures employed in existing studies. Turning to several sections of empirical review, we present and discuss evidence for links between prenatal and juvenile androgens and sexual attraction and aggression. This includes the proposal that adrenal androgens-DHEA and androstenedione-may play functional roles during juvenility as part of a life-stage specific system. We next review studies of adult male testosterone responses to competition, with these studies emphasizing men's involvement in individual and team sports. These studies show that men's testosterone responses differ with respect to variables such as playing home/away, winning/losing, and motivation. Field studies of human male hormones and sexual behavior also focus on testosterone, showing some evidence of patterned changes in men's testosterone to sexual activity. Moreover, life stage-specific changes in male androgens may structure age-related differences in sexual behavior, including decreases in sexual behavior with senescence. We overview the considerable body of research on male testosterone, partnerships and paternal care, noting the variation in social context and refinements in research design. A few field studies provide insight into relationships between partnering and paternal behavior and prolactin, oxytocin, and vasopressin. In the third section of the review, we discuss patterns, limitations and directions for future research. This includes discussion of conceptual and methodological issues future research might consider as well as opportunities for contributions in under-researched male life stages (juvenility, senescence) and hormones (e.g., vasopressin).

Sexuality among fathers of newborns in Jamaica.

BACKGROUND: While a growing body of research has addressed pregnancy and postpartum impacts on female sexuality, relatively little work has been focused upon men. A few studies suggest that a fraction of men report decreases in libido during a partner's pregnancy and/or postpartum, with alterations in men's sexual behavior also commonly aligning with those of a partner. Here, we investigate sexuality among fathers of newborn children in Jamaica. In Jamaica, as elsewhere in the Caribbean, relationship dynamics can be fluid, contributing to variable paternal roles and care, as well as a high fraction of children born into visiting relationships in which parents live apart from each other. METHODS: During July-September, 2011, 3410 fathers of newborns with an average age of 31 (SD = 8) years participated in the fatherhood arm of a national birth cohort study (JAKids). These fathers answered questions about sociodemographic background, relationship quality and sexuality (e.g., various components of sexual function such as sex drive and sexual satisfaction as well as number of sexual partners the previous 12 months and sexual intercourse the previous week) during a visit to a hospital or birth center within a day or two of their child being born. RESULTS: Showed that sex drive was more variable than other components (erections, ejaculation, problem assessment) of sexual function, though sexual satisfaction was generally high. Thirty percent of men reported two or more sexual partners the previous 12 months. Nearly half of men indicated not engaging in sexual intercourse the past week. Multivariate analyses showed that relationship status was related to various aspects of men's sexuality, such as men in visiting relationships reporting more sexual partners and more openness to casual sex. Relationship quality was the most consistent predictor of men's sexuality, with men in higher quality relationships reporting higher sexual satisfaction, fewer sexual partners, and higher frequency of sex, among other findings. CONCLUSIONS: These results provide an unusually large, quantitative look at men's sexuality during the transition to fatherhood in Jamaica, offering helpful insight to would-be parents, clinicians or others seeking to anticipate the effects of a partner's pregnancy on men's sexuality.

Evolution and human sexuality.

The aim of this review is to put core features of human sexuality in an evolutionary light. Toward that end, I address five topics concerning the evolution of human sexuality. First, I address theoretical foundations, including recent critiques and developments. While much traces back to Darwin and his view of sexual selection, more recent work helps refine the theoretical bases to sex differences and life history allocations to mating effort. Second, I consider central models attempting to specify the phylogenetic details regarding how hominin sexuality might have changed, with most of those models honing in on transitions from a possible chimpanzee-like ancestor to the slightly polygynous and long-term bonded sociosexual partnerships observed among most recently studied hunter-gatherers. Third, I address recent genetic and physiological data contributing to a refined understanding of human sexuality. As examples, the availability of rapidly increasing genomic information aids comparative approaches to discern signals of selection in sexuality-related phenotypes, and neuroendocrine studies of human responses to sexual stimuli provide insight into homologous and derived mechanisms. Fourth, I consider some of the most recent, large, and rigorous studies of human sexuality. These provide insights into sexual behavior across other national samples and on the Internet. Fifth, I discuss the relevance of a life course perspective to understanding the evolution of human sexuality. Most research on the evolution of human sexuality focuses on young adults. Yet humans are sexual beings from gestation to death, albeit in different ways across the life course, and in ways that can be theoretically couched within life history theory.

Examining the Impact of Virtual Animal Stimuli on College Students' Affect and Perception of their Academic Advising Experience.

The benefits of animal-assisted interventions (AAI) involving animals in therapy are widely accepted. The presence of animals in therapy can decrease a patient's reservation about therapy and promote a sense of comfort and rapport during the therapy process. Using survey data from college students (n = 152) attending a large public four-year institution, this study is the first to investigate the benefits of virtual animal stimuli during academic advising appointments. It posits that exposure to virtual animal stimuli can influence positive mental health and well-being in academic advising settings. Specifically, the research questions explored how different types of video content influence students' affect and how virtual animal stimuli impact students' perception of their advisor and university. College students were randomly assigned to watch one of four types of virtual stimuli (wild animals, companion animals, nature, and a control) prior to their advising session. Subjective measures were collected at baseline and after the advising session. Results indicated animal stimuli increase positive affect, and companion animal stimuli influence the student's perception of the advisor. This study supports the notion that companion animal videos positively impact students' well-being and interactions with their advisors and may have broader implications beyond the academic setting.

Aging and human sexual behavior: biocultural perspectives - a mini-review.

In this mini-review, we consider an evolutionary biocultural perspective on human aging and sexuality. An evolutionary approach to senescence highlights the energetic trade-offs between fertility and mortality. By comparing humans to other primates, we situate human senescence as an evolutionary process, with shifts in postreproductive sexual behavior in this light. Age-related declines in sexual behavior are typical for humans but also highly contingent on the sociocultural context within which aging individuals express their sexuality. We briefly review some of the most comprehensive studies of aging and sexual behavior, both from the USA and cross-culturally. We frame these patterns with respect to the long-term relationships within which human sexual behavior typically occurs. Because sexuality is typically expressed within pair-bonds, sexual behavior sometimes declines in both members of a couple with age, but also exhibits sex-specific effects that have their roots in evolved sex differences.

A Study Evaluating Consumer Motivations, Perceptions, and Responses to Direct-to-Consumer Canine Genetic Test Results.

Direct-to-consumer genetic services allow companion animal guardians to purchase a DNA test and receive detailed results about their pet's ancestry, health, and traits results. In collaboration with Wisdom Panel, we present novel findings about consumer motivations, perceptions, and responses to their use of canine genomic services. Wisdom Panel customers were invited to complete an online survey anonymously in which they were asked about their reasons for using a genetic test for their dog, how they perceived the test's results, and how they responded to the results they received. Participant data revealed most utilized a test that provided more ancestry/breed results (75.9%) as compared to health-related results. The majority of participants perceived the breed test results as accurate (52.0% strongly agree, 27.6% somewhat agree) and the genetic services provided as having great value (49.6% strongly agree, 32.7% somewhat agreed). In responding to their dog's results, participants indicated they shared the information with family (88.1%) and friends (84.2%). Collectively, our study indicates consumers are more focused on their dog's ancestry than other test results. Using these findings and previous literature on human direct-to-consumer genetic testing, human-animal dyads, and identity construction, we consider the possibility of "breed options theory" and future areas of research.

Exploratory content analysis of direct-to-consumer pet genomics: What is being marketed and what are consumers saying?

Mars Petcare introduced the first direct-to-consumer domestic dog genetic test in 2009 and Basepaws introduced the first direct-to-consumer cat genetic test in 2016. Social science research has evaluated numerous aspects of the human direct-to-consumer market, yet no such exploration has evaluated the occurrence of pet owners pursuing pet genetic tests. Using a mixed methods approach, we conducted an exploratory content analysis of direct-to-consumer pet genetic company webpages and consumer reviews shared on Amazon. Initial data reviews indicated some companies may be key industry players, relative to others. Our results present content frequency for each group (key industry players, all other companies), though the primary themes for each remained the same. Analysis showed genetic companies are primarily sharing product and purchasing information, along with trustworthiness to establish the merit of the company and their products. Companies also used statements directed towards pet owners that are suggestive of both pets and "pet parents" benefiting from the test results. The primary themes identified in consumer reviews involved consumers sharing their perception about the tests (e.g., accuracy), what aspects of the test results they focused on (e.g., breed information), and experiences with using the test (e.g., ease of use). Amazon reviews were primarily positive, though the companies with smaller review numbers had higher percentages of negative and ambiguous sentiments. Of interest, reviews most often indicated tests were being used to determine a pet's breed identity, while companies most frequently promoted the health advantages of using their products. Reviews revealed some consumers respond to tests by sharing their pet's results with someone or by altering their pet's care. Considering these results in addition to the growing popularity of this industry and the advancements of genomic technology, further research is needed to determine the role pet genetic testing may have in society and on human-animal relationships.

Salivary testosterone levels in men at a U.S. sex club.

Vertebrate males commonly experience elevations in testosterone levels in response to sexual stimuli, such as presentation of a novel mating partner. Some previous human studies have shown that watching erotic movies increases testosterone levels in males although studies measuring testosterone changes during actual sexual intercourse or masturbation have yielded mixed results. Small sample sizes, "unnatural" lab-based settings, and invasive techniques may help account for mixed human findings. Here, we investigated salivary testosterone levels in men watching (n = 26) versus participating (n = 18) in sexual activity at a large U.S. sex club. The present study entailed minimally invasive sample collection (measuring testosterone in saliva), a naturalistic setting, and a larger number of subjects than previous work to test three hypotheses related to men's testosterone responses to sexual stimuli. Subjects averaged 40 years of age and participated between 11:00 pm and 2:10 am. Consistent with expectations, results revealed that testosterone levels increased 36% among men during a visit to the sex club, with the magnitude of testosterone change significantly greater among participants (72%) compared with observers (11%). Contrary to expectation, men's testosterone changes were unrelated to their age. These findings were generally consistent with vertebrate studies indicating elevated male testosterone in response to sexual stimuli, but also point out the importance of study context since participation in sexual behavior had a stronger effect on testosterone increases in this study but unlike some previous human lab-based studies.

In the company of men: quality of life and social support among the Ariaal of northern Kenya.

To determine the age-related pattern of well-being among men and its predictors in a subsistence society, we collected anthropometric and questionnaire data among Ariaal pastoral nomads of northern Kenya. The sample consisted of 102 settled and 103 nomadic men ages 20 to 60+ stratified by 10 year age groups. Measures included questions from the WHO quality of life questionnaire (WHOQOL), anthropometrics, and hand grip strength, as well as questions about the number of friends and kin who gave material and emotional support. Results show that while reported quality of life declined significantly across age groups in both sub-populations, nomadic males reported significantly higher overall quality of life than did settled males. Support from other males, but not marital status, was a significant predictor of quality of life, controlled for age group and residence. Among the physical measures, % body fat was positively related to quality of life among the nomads, while grip strength was not related to quality of life. In a multivariate model, male support was the strongest predictor of quality of life. These results provide the first clear demonstration of age-related declines in male quality of life and the importance of social support to men's quality of life in a subsistence population.

Exploring women's oxytocin responses to interactions with their pet cats.

BACKGROUND: Extensive research has evaluated the involvement of the neuropeptide oxytocin (OT) in human social behaviors, including parent-infant relationships. Studies have investigated OT's connection to human attachment to nonhuman animals, with the majority of the literature focusing on domestic dogs (Canis lupis familiaris). Utilizing what is known about OT and its role in maternal-infant and human-dog bonding, we apply these frameworks to the study of human-domestic cat (Felis catus) interactions. METHODS: We investigated changes in salivary OT levels in 30 U.S. women of reproductive age before and after two conditions: reading a book (control) and interacting with their pet cat. Participant and cat behavioral patterns during the cat interaction condition were also quantified to determine if differences in women's OT concentrations were associated with specific human and cat behaviors. RESULTS: Our results revealed no changes in women's OT levels during the cat interaction, relative to the control condition, and pre-cat interaction OT levels. However, differences in women's OT concentrations were correlated with some human-cat interactions (e.g., positively with petting cat and cat approach initiation, negatively with cat agonistic behavior) but not all observed behaviors (e.g., use of gentle or baby voice) coded during human-cat interactions. DISCUSSION: This study is the first to explore women's OT in response to interactions with their pet cat and has identified distinct human and cat behaviors that influence OT release in humans.

Female social and sexual interest across the menstrual cycle: the roles of pain, sleep and hormones.

BACKGROUND: Although research suggests that socio-sexual behavior changes in conjunction with the menstrual cycle, several potential factors are rarely taken into consideration. We investigated the role of changing hormone concentrations on self-reported physical discomfort, sleep, exercise and socio-sexual interest in young, healthy women. METHODS: Salivary hormones (dehydroepiandrosterone sulfate-DHEAS, progesterone, cortisol, testosterone, estradiol and estriol) and socio-sexual variables were measured in 20 women taking oral contraceptives (OC group) and 20 not using OCs (control group). Outcome measures were adapted from questionnaires of menstrual cycle-related symptoms, physical activity, and interpersonal relations. Testing occurred during menstruation (T1), mid-cycle (T2), and during the luteal phase (T3). Changes in behavior were assessed across time points and between groups. Additionally, correlations between hormones and socio-behavioral characteristics were determined. RESULTS: Physical discomfort and sleep disturbances peaked at T1 for both groups. Exercise levels and overall socio-sexual interest did not change across the menstrual cycle for both groups combined. However, slight mid-cycle increases in general and physical attraction were noted among the control group, whereas the OC group experienced significantly greater socio-sexual interest across all phases compared to the control group. Associations with hormones differed by group and cycle phase. The estrogens were correlated with socio-sexual and physical variables at T1 and T3 in the control group; whereas progesterone, cortisol, and DHEAS were more closely associated with these variables in the OC group across test times. The direction of influence further varies by behavior, group, and time point. Among naturally cycling women, higher concentrations of estradiol and estriol are associated with lower attraction scores at T1 but higher scores at T3. Among OC users, DHEAS and progesterone exhibit opposing relationships with attraction scores at T1 and invert at T3. CONCLUSIONS: Data from this study show no change across the cycle in socio-sexual interest among healthy, reproductive age women but higher social and physical attraction among OC users. Furthermore, a broader range of hormones may be associated with attraction than previously thought. Such relationships differ by use of oral contraceptives, and may either reflect endogenous hormone modulation by OCs and/or self-selection of sexually active women to practice contraceptive techniques.

Women's use of intimate apparel as subtle sexual signals in committed, heterosexual relationships.

Current literature on women's sexual signaling focuses on modes of attracting potential, new sexual partners, but says little about women's subtle sexual signals in committed, romantic relationships. Subtle sexual signals are inherently private and are only visible to the intended audience; a woman might use these signals to elicit or accept a sexual response from her partner or to increase her overall attractiveness, or attractivity. In this study, we sought to identify women's use of intimate apparel as a proceptive or receptive behavior as well as the effects of relative mate value, relationship commitment, relationship satisfaction, and sexual functioning. A total of N = 353 women in the United States aged 25-45 who were in committed, heterosexual relationships completed the survey; 88.7% of the sample indicated wearing or having worn sexy underwear. Results indicate that women report wearing sexier underwear the day taking the survey if they anticipate sexual activity that same day. However, during the most recent sexual activity, women did not report wearing sexier underwear if they initiated (proceptive) that activity. While relative mate value was not directly related to sexiness of intimate apparel, women who report higher mate value tend to wear sexier underwear. Women's use of intimate apparel might be viewed as a method of increasing attractivity and underlying receptivity to aid relationship maintenance, though caveats regarding measures and alternative interpretations are also discussed. Findings suggest that these women use intimate apparel to feel sexy, desired, aroused, and to prepare for sex with their partners. This study is the first to examine intimate apparel in relationships and as a subtle sexual signal of proceptivity and receptivity.

Androgen receptor CAG repeats and body composition among Ariaal men.

To determine the population variation in the androgen receptor (AR) and its association with body composition in a subsistence population, we sampled 87 settled and 65 nomadic males ages 20+ among the Ariaal of northern Kenya. Anthropometric measures included height, body mass index, fat-free mass (FFM), upper arm muscle plus bone area (AMPBA), % body fat (%BF), suprailliac skinfold (SISF), and waist-to-hip ratio. Salivary testosterone (T) was determined from both morning (Am T) and afternoon (Pm T) samples. Hair roots were obtained for genotyping AR CAG repeat length. AR CAG repeat length did not vary between the two sub-groups (overall value = 22.6 +/- 3.1). Multiple regression models, controlling for age and residence, indicate that Pm T was positively associated with all measures of body composition. AR CAG repeat length was a significant positive predictor of height, FFM, %BF, SISF and waist circumference. There was a significant negative Pm T by AR CAG repeat length interaction in predicting all anthropometric measures but AMPBA. These findings provide evidence for population variation in AR CAG repeat length and suggest that both T and AR CAG length play a role in body composition in this extremely lean population.

Sex, Energy, Well-Being and Low Testosterone: An Exploratory Survey of U.S. Men's Experiences on Prescription Testosterone.

Prescription testosterone sales in the United States have skyrocketed in the last two decades due to an aging population, direct-to-consumer advertising, and prescriber views of the benefits and risks to testosterone, among other factors. However, few studies have attempted to directly examine patient experiences on prescription testosterone therapy. The present exploratory study involved an online self-report survey of U.S. testosterone patients who were at least 21 years of age. The primary focus was on patient perspectives concerning motivations leading to the initiation of testosterone therapy and the perceived effects of treatment. Responses to open-ended questions drew upon a coding scheme incorporating both inductive and deductive approaches, influenced by the clinical, male life history theory, and behavioral endocrinology literature. Results indicated that the most frequent reasons men gave for taking prescription testosterone were low testosterone (37.1%), well-being (35.2%), energy (28.7%), libido (21.9%), and social energy (19.4%); older men claimed libido as a motivation for testosterone initiation more frequently than younger men (p < 0.001). Men most frequently claimed testosterone improved their energy (52.3%), libido (41.9%), and muscle (28.5%). Results are interpreted in the context of medical, life history theoretical and behavioral endocrinology approaches, including an emphasis on sex and energy.

An Exploration of Attitudes Toward Dogs among College Students in Bangalore, India.

Conversations in the field of anthrozoology include treatment and distinction of food animals, animals as workers versus pests, and most recently, emerging pet trends including the practice of pet parenting. This paper explores attitudes toward pet dogs in the shared social space of urban India. The data include 375 pen-and-paper surveys from students at CHRIST (Deemed to be University) in Bangalore, India. Reflecting upon Serpell's biaxial concept of dogs as a relationship of affect and utility, the paper considers the growing trend of pet dog keeping in urban spaces and the increased use of affiliative words to describe these relationships. The paper also explores potential sex differences in attitudes towards pet and stray dogs. Ultimately, these findings suggest that the presence of and affiliation with pet dogs, with reduced utility and increased affect, is symptomatic of cultural changes typical of societies encountering the second demographic transition. Despite this, sex differences as expected based upon evolutionary principles, remain present, with women more likely to emphasize health and welfare and men more likely to emphasize bravery and risk taking.