bluuebunny/crossref_metadata_2025 huggingface dataset:
The First Joke: Exploring the Evolutionary Origins of Humor
Authors: Polimeni Joseph , Reiss Jeffrey P.
Published: July 2015

Humor is a complex cognitive function which often leads to laughter. Contemporary humor theorists have begun to formulate hypotheses outlining the possible innate cognitive structures underlying humor. Humor's conspicuous presence in the behavioral repertoire of humankind invites adaptive explanations. This article explores the possible adaptive features of humor and ponders its evolutionary path through hominid history. Current humor theories and previous evolutionary ideas on humor are reviewed. In addition, scientific fields germane to the evolutionary study of humor are examined: animal models, genetics, children's humor, humor in pathological conditions, neurobiology, humor in traditional societies and cognitive archeology. Candidate selection pressures and associated evolutionary mechanisms are considered. The authors conclude that several evolutionary-related topics such as the origins of language, cognition underlying spiritual feelings, hominid group size, and primate teasing could have special relevance to the origins of humor.
Natural Information Processing Systems
Authors: Sweller John , Sweller Susan
Published: July 2015

Natural information processing systems such as biological evolution and human cognition organize information used to govern the activities of natural entities. When dealing with biologically secondary information, these systems can be specified by five common principles that we propose underlie natural information processing systems. The principles equate: (1) human long-term memory with a genome; (2) learning from other humans with biological reproduction; (3) problem solving through random generate and test with random mutation; (4) working memory when processing novel information with the epigenetic system managing environmental information; (5) long-term working memory with the epigenetic system managing genomic information. These five principles provide an integrated perspective for the nature of human learning and thought. They also have implications for the presentation of information.
Sex Differences in Jealousy in Response to Actual Infidelity
Authors: Edlund John E. , Heider Jeremy D. , Scherer Cory R. , Farc Maria-Magdalena , Sagarin Brad J.
Published: July 2015

The present studies address two criticisms of the theory of evolved sex differences in jealousy: (a) that the sex difference in jealousy emerges only in response to hypothetical infidelity scenarios, and (b) that the sex difference emerges only using forced-choice measures. In two separate studies, one a paper-and-pencil survey with a student sample and the other a web-based survey targeting a non-student sample, men and women showed significant sex differences in jealousy in response to actual infidelity experiences; men experienced more jealousy in response to the sexual aspects of an actual infidelity, whereas women experienced more jealousy in response to the emotional aspects of the infidelity. Sex differences emerged using both continuous measures of jealousy as well as the traditional forced-choice measure. Overall, our results demonstrate that sex differences in jealousy are not limited to responses to hypothetical infidelity scenarios; they also emerge in response to actual infidelity experiences.
Evolutionary Theory's Increasing Role in Personality and Social Psychology
Authors: Webster Gregory D.
Published: July 2015

Has the emergence of evolutionary psychology had an increasing impact on personality and social psychological research published over the past two decades? If so, is its growing influence substantially different from that of other emerging psychological areas? These questions were addressed in the present study by conducting a content analysis of the Journal of Personality and Social Psychology (JPSP) from 1985 to 2004 using the PsycINFO online abstract database. Specifically, keyword searches for “evol*” or “Darwin*” revealed that the percentage of JPSP articles drawing on evolutionary theory was modest, but increased significantly between 1985 and 2004. To compare the growing impact of evolutionary psychology with other psychological areas, similar keywords searches were performed in JPSP for emotion and motivation, judgment and decision making, neuroscience and psychophysiology, stereotyping and prejudice, and terror management theory. The increase in evolutionary theory in JPSP over time was practically equal to the mean increase over time for the other five areas. Thus, evolutionary psychology has played an increasing role in shaping personality and social psychological research over the past 20 years, and is growing at a rate consistent with other emerging psychological areas.
Yawning as a Brain Cooling Mechanism: Nasal Breathing and Forehead Cooling Diminish the Incidence of Contagious Yawning
Authors: Gallup Andrew C. , Gallup Gordon G.
Published: July 2015

We conducted two experiments that implicate yawning as a thermoregulatory mechanism. The first experiment demonstrates that different patterns of breathing influence susceptibility to contagious yawning. When participants were not directed how to breathe or were instructed to breathe orally (inhaling and exhaling through their mouth), the incidence of contagious yawning in response to seeing videotapes of people yawning was about 48%. When instructed to breathe nasally (inhaling and exhaling through their nose), no participants exhibited contagious yawning. In a second experiment, applying temperature packs to the forehead also influenced the incidence of contagious yawning. When participants held a warm pack (460C) or a pack at room temperature to their forehead while watching people yawn, contagious yawning occurred 41% of the time. When participants held a cold pack (40C) to their forehead, contagious yawning dropped to 9%. These findings suggest that yawning has an adaptive/functional component that it is not merely the derivative of selection for other forms of behavior.
Greater Emphasis on Female Attractiveness in Homo Sapiens: A Revised Solution to an Old Evolutionary Riddle
Authors: Gottschall Jonathan
Published: July 2015

Substantial evidence from psychology and cross-cultural anthropology supports a general rule of greater emphasis on female physical attractiveness in Homo sapiens. As sensed by Darwin (1871) and clarified by Trivers (1972) , generally higher female parental investment is a key determinant of a common pattern of sexual selection in which male animals are more competitive, more eager sexually and more conspicuous in courtship display, ornamentation, and coloration. Therefore, given the larger minimal and average parental investment of human females, keener physical attractiveness pressure among women has long been considered an evolutionary riddle. This paper briefly surveys previous thinking on the question, before offering a revised explanation for why we should expect humans to sharply depart from general zoological pattern of greater emphasis on male attractiveness. This contribution hinges on the argument that humans have been seen as anomalies mainly because we have been held up to the wrong zoological comparison groups. I argue that humans are a partially sex-role reversed species, and more emphasis on female physical attractiveness is relatively common in such species. This solution to the riddle, like those of other evolutionists, is based on peculiarities in human mating behavior, so this paper is also presented as a refinement of current thinking about the evolution of human mating preferences.
Relations among Individual Differences in Reproductive Strategies, Sexual Attractiveness, Affective and Punitive Intentions, and Imagined Sexual or Emotional Infidelity
Authors: Jones Daniel N. , Figueredo Aurelio José , Dickey Erin Denise , Jacobs W. Jake
Published: July 2015

We examined relations among Mating Effort, Mate Value, Sex and individuals' self-reported responses to imagined sexual or emotional infidelity. We asked participants to describe the (1) upset or bother (2) aversive emotional reactions (3) punitive impulses, and (4) punitive intentions they experienced in response to imagined sexual or emotional infidelity. The results replicated previously documented sex differences in jealousy. In addition, imagined sexual infidelity upset individuals higher in Mating Effort more than those lower in Mating Effort. Higher Mating Effort also predicted greater temptation, intention, and likelihood to engage in punitive behaviors in response to imagined sexual or emotional infidelity. We discuss these data in light of individual differences in relations between reproductive strategy and romantic jealousy. Additionally, we point to the importance of controlling for co-linearity between reactions to sexual and emotional infidelity, and the need for addressing related methodological problems within jealousy research.
Economic Transition, Male Competition, and Sex Differences in Mortality Rates
Authors: Kruger Daniel J. , Nesse Randolph M.
Published: July 2015

Sex differences in mortality rates stem from a complex set of genetic, physiological, psychological, and social causes whose interconnections are best understood in an integrative evolutionary framework. We predicted that the transition from centrally planned to market economies in Eastern Europe inflated the discrepancy between male and female mortality rates, because economic uncertainty and increasing variation and skew in social status and resources should increase risky male behavior and the impact of stress on physiological susceptibility to internal causes of death. We computed the ratio of the male mortality rate to the female mortality rate separately for 14 Eastern European countries and for the combined population of 12 Western European countries in the pre-transition (1985–1989), transition (1990–1994), and post-transition (1995–1999) periods. We found that the Male to Female Mortality Ratio (M:F MR) for 14 Eastern European nations increased during the years of economic transition, most prominently during early adulthood. Larger sex differences in mortality rates occurred in both young adulthood, reflecting a shift towards riskier behavioral strategies, and middle adulthood, indicating greater physiological susceptibility to stress. For 12 of the 14 Eastern European nations, the increase was substantially larger than the slight increase in the overall Western European M:F MR. The impact of the transition on the magnitude of mortality discrepancy across countries varies considerably and likely reflects conditions particular to each country. These findings illustrate how traits shaped by natural selection interact with environmental conditions to influence male psychology and ultimately mortality patterns.
We Recognize Ourselves as Being Similar to Others: Implications of the “Social Brain Hypothesis” for the Biological Evolution of the Intuition of Freedom
Authors: Voland Eckart
Published: July 2015

Consistent with and in extension of the “social brain hypothesis,” I discuss the idea that the intuition of free will emerged during the course of primate social evolution. If, as the “social brain hypothesis” alleges, the main selective pressure among primates is on generating social knowledge about one's cooperators and competitors, then it is the knowledge about others and not the knowledge about oneself that is the scarce cognitive resource. It is beneficial to make the others predictable and to form hypotheses about their probable behavioral tendencies. This is done by behavior reading and mind reading and by classifying the recurring stochastic patterns in everyday language as the “will.” Thus, the idea of free will emerged first as a social attribution and not as an introspectively gained insight. The fact that ego applies the idea of freedom also to itself and considers itself to be as free as it considers the social partners to be free, i.e. unpredictable, is in this view a non-selected by-product of social intelligence.
The Effect of Mood on Opposite-Sex Judgments of Males' Commitment and Females' Sexual Intent
Authors: de Quadros-Wander Shikkiah , Stokes Mark
Published: July 2015

Gender differences in perceptions of sexual intent and commitment have been the subject of formal and informal inquiry for considerable time. One evolutionary theory, Error Management Theory (EMT), predicts that opposite-sex perceptions of female sexual intent and male commitment intent reflect intrinsic biases that minimize gender-specific evolutionary costs. The results supporting these hypotheses were obtained from subjects regardless of mood. We hypothesized that mood would influence ratings of sexual and commitment intent. Sixty participants (30 males, 30 females) were recruited and exposed to a positive and negative mood condition in counterbalanced groups using video stimuli. Preliminary analyses found an unexpected effect of order of mood induction, necessitating separate analyses of the Positive-Negative (PN) and Negative-Positive (NP) groups. Contrary to the original study, there were no gender effects. Positive moods led to increased ratings of both sexual and commitment intent across genders. Further, negative to positive mood-change was associated with significantly increased ratings. Both males and females attributed significantly higher sexual intent to same-sex rivals than themselves, but only males assessed themselves as having significantly higher commitment intent than same-sex rivals. The EMT model may require adaptation to acknowledge effects of variables such as mood on its predictions of gender-specific biases.
The Functional Design of Depression's Influence on Attention: A Preliminary Test of Alternative Control-Process Mechanisms
Authors: Andrews Paul W. , Aggen Steven H. , Miller Geoffrey F. , Radi Christopher , Dencoff John E. , Neale Michael C.
Published: July 2015

Substantial evidence indicates that depression focuses attention on the problems that caused the episode, so much that it interferes with the ability to focus on other things. We hypothesized that depression evolved as a response to important, complex problems that could only be solved, if they could be solved at all, with an attentional state that was highly focused for sustained periods. Under this hypothesis, depression promotes analysis and problem-solving by focusing attention on the problem and reducing distractibility. This predicts that attentionally demanding problems will elicit depressed affect in subjects. We also propose two control-process mechanisms by which depression could focus attention and reduce distractibility. Under these mechanisms, depression exerts a force on attention like that of a spring when it is pulled or like a magnet on a steel ball. These mechanisms make different predictions about how depressed people respond emotionally to a task that pulls attention away from their problems. We tested these predictions in a sample of 115 undergraduate students. Consistent with our main prediction, initially non-depressed subjects experienced an increase in their depressed affect when exposed to an attentionally demanding task. Moreover, the overall pattern of results supported the magnet metaphor.
Sex Differences in Romantic Kissing among College Students: An Evolutionary Perspective
Authors: Hughes Susan M. , Harrison Marissa A. , Gallup Gordon G.
Published: July 2015

This study provides a descriptive account of kissing behavior in a large sample of undergraduate college students and considers kissing in the context of both short-term and long-term mating relationships. Kissing was examined as a mate assessment device, a means of promoting pair bonds, and a means of inducing sexual arousal and receptivity. A total 1,041 college students completed one of three questionnaires measuring kissing preferences, attitudes, styles, and behaviors. Results showed that females place more importance on kissing as a mate assessment device and as a means of initiating, maintaining, and monitoring the current status of their relationship with a long-term partner. In contrast, males place less importance on kissing, especially with short-term partners, and appear to use kissing to increase the likelihood of having sex. The results suggest that kissing may play an important role as an adaptive courtship/mating ritual.
Testing Predictions from the Hunter-Gatherer Hypothesis — 1: Sex Differences in the Motor Control of Hand and Arm
Authors: Sanders Geoff , Walsh Tom
Published: July 2015

Here, in the first of two reports that test predictions from the hunter-gatherer hypothesis, we focus on sex differences in motor control. Published evidence confounds the cognitive demands, the muscles used and the spatial location in which tasks are performed. To address these issues our participants used hand or arm movements to track a moving target within near space. Study 1 identified an optimal level of task difficulty for the differentiation of male and female performance and showed that women tracked better using their hands and men using their arms. Employing the optimal level of task difficulty, Study 2 replicated the findings of Study 1 and, for men, demonstrated a significant correlation between arm tracking and performance on the nonmotor sex-dimorphic Mental Rotations task. This correlation suggests that the same or related events are responsible for the development of sex differences in motor and cognitive systems. The distal (hand) muscles are controlled by the primary motor cortex via two dorsolateral corticospinal tracts whereas the proximal (arm) muscles are controlled via two ventromedial corticospinal tracts. Our findings point to possible sex differences in these two neural pathways and they are compatible with an evolutionary origin as predicted by the hunter-gatherer hypothesis.
What's in a Name: Is “Evolutionary Psychology” Eclipsing “Sociobiology” in the Scientific Literature?
Authors: Webster Gregory D.
Published: July 2015

Is the term “evolutionary psychology” supplanting “sociobiology” in the scientific literature? How influential was E. O. Wilson's (1975) book, Sociobiology, in establishing the discipline of the same name? Similarly, how influential were the two Tooby-Cosmides chapters appearing in The Adapted Mind ( Cosmides and Tooby, 1992 ; Tooby and Cosmides, 1992 ) in establishing evolutionary psychology as a viable outgrowth of sociobiology? The purpose of the present research was to answer these questions using quantitative analyses of publication trends. The Internet search engine Google Scholar was used to count the number of hits (i.e., the number of scholarly works, citations, etc.) for “sociobiology” and “evolutionary psychology” separately per year from 1960 to 2003. Interrupted time-series analyses revealed significant increases (intercept shifts) for sociobiology hits between 1974 and 1975, and for evolutionary psychology hits between 1991 and 1992. Evolutionary psychology hits also experienced a significant increase in change-over-time (a slope shift) between 1991 and 1992. Growth curve analyses revealed that the rate of growth for evolutionary psychology, which was accelerating over time, was significantly greater than that for sociobiology, which was decelerating. The implications of these findings for understanding the histories of sociobiology and evolutionary psychology are discussed.
Helping Others to Find Long-Term and Short-Term Mates: A Test of Inclusive Fitness, Reciprocal Altruism, and Parental Investment Theories
Authors: Jonason Peter K. , Izzo Pamela L. , Webster Gregory D.
Published: July 2015

Individuals prefer helping some people more that others when it comes to finding a mate, and these preferences depend on whether long- or short-term mates are considered. Study 1 ( N = 108) examined three theoretical frameworks (inclusive fitness, reciprocal altruism, and parental investment) for understanding why individuals would be more willing to help some individuals find mates instead of others. College participants reported how willing they were to help different types of individuals (e.g., sister, stranger) find a mate. When considering willingness to help others find a long-term mate, people preferred kin over nonkin, supporting an inclusive fitness model. However, when considering willingness to help others find short-term mates, people preferred helping people their own age, supporting a reciprocal altruism model. Study 2 ( N = 143) replicated this age-cohort effect. Although rates of willingness to help others find mates were generally low, people were more likely to help others find a long-term mate than a short-term one.
Neither Daredevils Nor Wimps: Attitudes toward Physical Risk Takers as Mates
Authors: Farthing G. William
Published: July 2015

Farthing (2005) tested a prediction derived from costly-signaling theory, that women would prefer physical risk takers (brave, athletic, fit) over risk-avoiders as long-term mates. Using scenarios involving high-risk acts, the prediction was confirmed for heroic (brave, altruistic) but not for non-heroic (brave, non-altruistic) acts. Apparently, women's concerns over risks to their mates overrode any positive signal value of men's risk taking, when the acts were highly risky and had no redeeming practical value.

The present studies revisited the costly-signaling hypothesis using both medium- and high-risk scenarios, and it was predicted that for non-heroic acts women would prefer risk takers over risk avoiders for medium-level risks but not for highly risky acts. The prediction was supported in two studies. In Study 1, risk takers were preferred for non-heroic medium-risk acts, but risk avoiders were preferred for high-risk acts. For heroic acts, risk takers were preferred for both high- and medium-risk acts. Study 2 crossed two act risk levels with two actor skill levels, with non-heroic risks. Risk takers were preferred for the least risky combination (medium-risk act, high-skill actor) and also for the two moderately risky combinations, but risk avoiders were preferred for the riskiest combination (high-risk act, medium-skill actor). In Study 1, participants compared high-level risk takers versus risk avoiders on several person adjectives. Both heroic and non-heroic risk takers were perceived as more brave, athletic, physically fit, impulsive, attention-seeking, and foolish, and less emotionally stable and self-controlled, compared to risk avoiders. But only heroic risk takers were perceived as more altruistic, agreeable, conscientious, and sexy than risk avoiders.
Perceptions of Child Facial Cues as a Function of Child Age
Authors: Volk Anthony A , Lukjanczuk Janeen L. , Quinsey Vernon L.
Published: July 2015

Child facial cues are known to influence adults' perceptions, attributions, and parental care behaviors. But how does the influence of these cues change with age? There are three competing theories regarding the influence of age on child facial cues: younger cues have the strongest influence, older cues have the strongest influence, and age cues do not influence adults. There are empirical findings that provide support for each of these hypotheses. Because previous studies have not focused on measures of adults' desire to provide parental care and have used limited stimulus sets and/or statistics, we conducted two studies to determine how age-related changes in child faces influenced adults' perceptions and ratings in the Hypothetical Adoption Paradigm. We presented approximately 200 adults with images of 12 different children at eight different ages (from six months to six years). Adults' ratings of adoption preference and cuteness were strongly and negatively related to the age of the child facial stimuli, while there was no consistent relationship between child age and adults' ratings of health. Our results support the hypothesis that facial cues associated with younger ages are most effective at eliciting adult responses associated with parental care.
Maternal Grandmothers Do Go the Extra Mile: Factoring Distance and Lineage into Differential Contact with Grandchildren
Authors: Pollet Thomas V. , Nettle Daniel , Nelissen Mark
Published: July 2015

Several studies conducted from an evolutionary perspective have documented differential investment in grandchildren by lineage. The majority of these studies have used retrospective ratings by grandchildren, but only a fraction of these studies have examined actual grandparental behavior. Here we focus on the interaction between distance and lineage on face-to-face contact with a (random) grandchild in a large scale sample. Our main prediction is that maternal grandparents are significantly more willing to travel in order to see their grandchild. While controlling for initiative of contact, urbanization, sex and age of the grandchild, educational attainment, marital status and age we found a significant interaction between distance and grandparent type on frequency of contact with a grandchild. Maternal grandmothers were significantly more inclined than paternal grandfathers and grandmothers to maintain frequent face-to-face contact, as distance between grandparent and grandchild increased. The results are discussed with reference to evolutionary theories of grandparental investment.
Evolutionary Lifestyle and Mental Health
Authors: Heath Christopher J. , Berman Jeffrey S.
Published: July 2015

Some have suggested that psychological distress may be lower if individuals adopt a lifestyle more similar to our evolutionary past. In this study, we assessed relationships between distress and six lifestyle elements (sleep, omega-3 consumption, exercise, rumination, sunlight exposure, and socialization). A large sample ( N = 495) of college undergraduates reported levels of each lifestyle element and their distress on the Beck Depression Inventory and Hopkins Symptom Checklist. Analysis revealed a positive relationship for rumination and a curvilinear relationship for sleep. In contrast, none of the other elements correlated reliably with distress. The findings raise the possibility that relationships between these lifestyle elements and distress may not be critical for the range of exposure typically experienced in a normal, nonclinical population.
Female Mate Choice is Influenced by Male Sport Participation
Authors: Schulte-Hostedde Albrecht I. , Eys Mark A. , Johnson Krista
Published: July 2015

Sexual selection theory argues that females invest more heavily in reproduction than males and thus tend to be choosier in terms of mate choice. Sport may provide a context within which females can gain information about male quality to inform this choice. Males may be able to display attractive traits such as athleticism, strength, and physique to females while participating in sport. We predicted that females would favor males that participated in team sports over individual sports and non-athletes because team sport athletes may be more likely to display qualities such as the ability to work well with others and role acceptance. We used a questionnaire, a photograph, and manipulated descriptions to gauge the effects of sport involvement, attractiveness, and status on 282 females' willingness to participate in various types of relationships. Team sport athletes were perceived as being more desirable as potential mates than individual sport athletes and non-athletes. It is suggested that team sport athletes may have traits associated with good parenting such as cooperation, likeability, and role acceptance, and/or these athletes may be better able to assert dominance in a team setting. Results are discussed in terms of further implications and future research.
Sex-of-Offspring Differences between Mothers
Authors: Grant Valerie J.
Published: July 2015

Evolutionary biologists and psychologists have long been aware of maternal effects on the secondary sex ratio in mammals. Up till now these have appeared inconsistent but re-analysis of the evidence, focusing on normally distributed maternal testosterone and its physiological and behavioral sequelae, reveals some support for the existence of sex-of-offspring differences between mothers. In addition to the animal studies showing a relationship between maternal, testosterone-based dominance and the secondary sex ratio, research on human mothers shows sex-of-offspring differences in a range of testosterone—related attributes (physiological, behavioral and cognitive) measured at varying times from before the child was conceived to the mother's maturity. Further exploration of these differences might help elucidate the problems surrounding sex determination in mammals.
Hagen Replies to Hirschfeld (2008)
Authors: Hagen L. Kirk
Published: July 2015

Hirschfeld's (2008) thoughtful comments on my article on the bilingual brain are a valuable contribution to what I find to be an exciting and fruitful interdisciplinary investigation in evolutionary linguistics. I think his reply will help us flesh out both the biological and the environmental forces that have led to the human endowment for language. Even so, Hirschfeld's conclusion — that the well-known difficulties which adults face in acquiring second languages are somehow proof of an environment in which early hominid bands frequently commingled - is at variance with virtually everything we know from the many disciplines that are now involved in the debate over the evolutionary origins of language.
Cross-National Variation in the Motivation for Uncommitted Sex: The Role of Disease and Social Risks
Authors: Barber Nigel
Published: July 2015

Evolutionary psychological meta-theory predicts that interest in “casual” sex should decline with its costs (e.g., acquiring HIV/AIDS or an infectious disease, unwanted pregnancy, loss of spousal commitment). Analyses of Schmitt's (2005) data on sociosexuality in 48 countries (including gender differences therein) tested these predictions using multiple regressions controlling for economic development and population density. Sociosexuality declined as HIV/AIDS increased and as teen births increased, supporting the hypothesis, but female sociosexuality increased with the risk of infectious disease. Sociosexuality was lower in countries in which there was a greater proportion of men in the population and marriages likely involved greater commitment. Country differences in sexual motivation partly reflect varying costs of extramarital sexuality with females possibly increasing their interest in sexual variety to boost heritable disease resistance.
Parent-Offspring Conflict over Mating: The Case of Beauty
Authors: Apostolou Menelaos
Published: July 2015

In pre-industrial societies parents exercise a strong influence over the mating decisions of their offspring. As modern pre-industrial societies approximate the way of life in ancestral human societies, human mating behavior should be seen as the outcome of a co-evolutionary process between parental and offspring's mating choice. Both parents and offspring have evolved mating preferences, which enable them to select those mates and in-laws who maximize their inclusive fitness. Following Trivers' (1974) theory of parent-offspring conflict, it is hypothesized that in-law and mating preferences substantially overlap, but also differ with respect to the beauty trait of a mating candidate. This hypothesis is tested on a sample of 292 parents. It is found that the two sets of preferences are strongly correlated, while beauty is preferred significantly more in a mating partner than in an in-law.
The Impact of Prior Heterosexual Experiences on Homosexuality in Women
Authors: Harrison Marissa A. , Hughes Susan M. , Burch Rebecca L. , Gallup Gordon G.
Published: July 2015

An abundance of unwanted sexual opportunities perpetrated by insensitive, physically and sexually abusive men may be a factor in the expression of homosexuality in some women. In the present study, we examined self-reports of dating histories, sexual experiences, and physical and sexual abuse among lesbians and heterosexual women. Lesbians with prior heterosexual experience reported more severe and more frequent physical abuse by men. Lesbians also reported more instances of forced, unwanted sexual contact perpetrated by men, and this sexual abuse occurred at a significantly earlier age. These data show that adverse experiences with the opposite sex are more common in lesbians than heterosexual women, and therefore negative heterosexual experiences may be a factor in the expression of a same-sex sexual orientation in women. We propose an evolutionary psychological interpretation of this phenomenon based on the cardinally different mating strategies of women and men that have evolved for maximizing the likelihood of reproduction.
High Status Men (but Not Women) Capture the Eye of the Beholder
Authors: DeWall C. Nathan , Maner Jon K.
Published: July 2015

Two studies tested the hypothesis that people attend preferentially to high status men (but not women). Participants overestimated the frequency of high status men in rapidly presented arrays (Experiment 1) and fixated their visual attention on high status men in an eye-tracking study (Experiment 2). Neither study showed any evidence of preferential attention to high status women, but there was evidence that physically attractive women captured attention. The results from both studies support evolutionary theories regarding differential prioritization of social status and physical attractiveness in men versus women. These findings illustrate how examination of early-in-the-stream social cognition can provide useful insights into the adapted mind.
Physique Correlates with Reproductive Success in an Archival Sample of Delinquent Youth
Authors: Genovese Jeremy E. C.
Published: July 2015

This study examines predictions from evolutionary psychology about relationships between physique and reproductive success using longitudinal data on 200 delinquent youth from Sheldon's (1949) somatotype research. Number of children (offspring count) in 1979 was used as the measure of reproductive success. Nonparametric bootstrap correlations and confidence intervals were calculated between offspring count and 11 measures of physique (endomorphy, mesomorphy, ectomorphy, andromorphy, gynomorphy, primary structural integration, secondary structural integration, general strength, hand strength, height, and weight). There were noteworthy correlations with mesomorphy, andromorphy, gynomorphy, primary structural integration, secondary structural integration, general strength, and hand strength, all in the directions predicted by evolutionary psychology. While no prediction was made for endomorphy, ectomorphy, or weight; height was expected to be correlated with offspring count, but this study did not find support for this relationship.
Coping with Romantic Betrayal: Sex Differences in Responses to Partner Infidelity
Authors: Miller Saul L. , Maner Jon K.
Published: July 2015

The current research tested the hypothesis that, because infidelity entails somewhat different negative consequences for men and women, men and women display different emotional and behavioral reactions aimed at reducing the costs of infidelity. The study utilized an open-response method in which participants wrote about their reactions to an imagined infidelity. Findings suggest that, in response to partner infidelity, men display greater feelings of anger and a greater propensity for violence (particularly toward the male interloper), whereas women display greater feelings of sadness and a greater inclination toward seeking out sources of compensatory social affiliation (particularly from existing friendships). The current research is some of the first to identify functional responses designed to help women and men offset the social costs inflicted by a partner's infidelity.
Socioeconomic Development and Shifts in Mate Preferences
Authors: Stone Emily A. , Shackelford Todd K. , Buss David M.
Published: July 2015

Mate preferences shift according to contexts such as temporal duration of mateship sought and ecological prevalence of parasites. One important cross-cultural context that has not been explored is a country's socioeconomic development. Because individuals in less developed countries are generally less healthy and possess fewer resources than those in more developed countries, displays of health and resources in a prospective long-term partner were hypothesized to be valued more in populations in which they are rare than in populations in which they are more common. We also predicted negative correlations between development and preferences for similar religious background and a desire for children. We found strong support for the health hypothesis and modest support for the resource acquisition potential hypothesis. We also found an unpredicted positive correlation between development and importance ratings for love. Discussion addresses limitations of the current research and highlights directions for future cross-cultural research on mating psychology.
Men's Faces Convey Information about their Bodies and their Behavior: What you see is what you get
Authors: Shoup Melanie L. , Gallup Gordon G.
Published: July 2015

We investigated whether men's faces contain embedded cues that signal differences in individual fitness. Data on shoulder-to-hip ratios (SHR), grip strength, sexual history, and facial photographs were collected from male college students. Female college students rated the photographs for attractiveness We found a striking relationship between ratings of facial attractiveness and body morphology. Males with attractive faces had significantly more masculine, wedge-shaped SHRs. Ratings of facial attractiveness accounted for over 25% of the variance in this sexually dimorphic dimension of male body configuration. Male students with attractive faces also had higher grip strength scores, and more sexual partners. These findings are consistent with a growing body of evidence showing that facial features contain important cues to fitness and hormonal status.
Developmental Instability and Markers of Schizotypy in University Students
Authors: Thoma Robert J. , Gangestad Steven W. , Euler Matthew J. , Lysne Per A. , Monnig Mollie , Yeo Ronald A.
Published: July 2015

Fluctuating asymmetries (FA) and minor physical anomalies (MPAs) are markers of developmental instability (DI), an index of the degree to which an organism was subject to genomic or environmental stress during development. Measures of DI are characteristic of schizophrenia and are thought to reflect an underlying genetic liability for schizophrenia spectrum disorders. Whereas MPAs reflect developmental stress relatively early in the first trimester in utero, skeletal FAs reflect developmental stress throughout the lifespan. Both measures were collected to provide some indication of the associated developmental time course. In addition to DI measures, several psychometric measures of schizotypy were administered in a sample of university students ( n = 81). It was hypothesized that increased DI may relate to schizotypal symptoms in a group of healthy undergraduate students. Schizotypy scores were positively correlated with FA, but not MPAs. This finding suggests that DI, as indexed by FA, is important for normal range variation in schizotypal characteristics, just as it is important for normal range variation in intelligence. Second, considered in the context of studies demonstrating that schizophrenia is associated with elevated MPAs, these results suggest that developmental stress likely occurs earlier in development for schizophrenia than schizotypy.
Male Financial Consumption is Associated with Higher Mating Intentions and Mating Success
Authors: Kruger Daniel J.
Published: July 2015

Cross-culturally, male economic power is directly related to reproductive success. Displays of wealth and social status are an important part of human male mating effort. The degree of male financial consumption may be related to variance in life history strategies, as differences in life history patterns are fundamentally differences in the allocation of effort and/or resources. Males who have higher mating intentions may maximize their economic displays, saving little and even spending beyond their capacity through the use of credit. These men may seek and possibly obtain a greater number of sexual partners. This hypothesis was tested in a randomly selected community sample of men aged 18–45 included in a telephone health interview. The degree of financial consumption was directly related to future mating intentions and past mating success, even when accounting for age, years of education completed, and marital status. The degree of financial consumption was not related to future mating intentions or past mating success for women in the same sample.
Fluctuating Asymmetry and Individual Variation in Regional Gray and White Matter Volumes: A Voxel-Based Morphometry Study
Authors: Euler Matthew , Thoma Robert J. , Parks Lauren , Gangestad Steven W. , Yeo Ronald A.
Published: July 2015

Composite measures of fluctuating asymmetry (FA) of skeletal features are commonly used to estimate developmental instability (DI), the imprecise expression of developmental design due to perturbations during an individual's growth and maturation. Though many studies have detailed important behavioral correlates of FA, very little is known about its possible neuroanatomical correlates. In this study we obtained structural brain MRI scans from 20 adults and utilized voxel-based morphometry (VBM) to identify specific regions linked to FA. Greater FA predicted greater whole brain white matter volume, and a trend in the same direction was noted for whole brain gray matter volume. Greater FA was associated with significantly greater gray and white matter volumes in discrete brain regions, most prominently in the frontal lobes and in the right cerebral hemisphere. Developmental studies are needed to identify when FA-related brain differences emerge and to elucidate the specific neurobiological mechanisms leading to these differences.
Solutions to the Problem of Diminished Social Interaction
Authors: Jonason Peter K. , Webster Gregory D. , Lindsey A. Elizabeth
Published: July 2015

Social animals, like humans, need to interact with others, but this is not always possible. When genuine social interaction is lacking, individuals may seek out or use sources of interaction that co-opt agency detection mechanisms vis-à-vis the human voice and images of people, called social snacking. Study 1 ( N = 240) found that ratings of how alone participants felt were correlated with frequency of talking to themselves and using the TV for company. Study 2 ( N = 66) was a daily diary study where loneliness was correlated with both Study 1 behaviors and singing to oneself. These solutions essentially trick the person's brain into feeling like they are socially interacting, thus, appeasing the relative dependence humans have on social interaction. Social snacking may satisfy one's need for social interaction because humans are unlikely to be able to differentiate between virtual and real people because this distinction did not exist in ancestral environments.
Humor as a Mental Fitness Indicator
Authors: Howrigan Daniel P. , MacDonald Kevin B.
Published: July 2015

To explain the pervasive role of humor in human social interaction and among mating partner preferences, Miller (2000a) proposed that intentional humor evolved as an indicator of intelligence. To test this, we looked at the relationships among rater-judged humor, general intelligence, and the Big Five personality traits in a sample of 185 college-age students (115 women, 70 men). General intelligence positively predicted rater-judged humor, independent of the Big Five personality traits. Extraversion also predicted rater-judged humor, although to a lesser extent than general intelligence. General intelligence did not interact with the sex of the participant in predicting rating scores on the humor production tasks. The current study lends support to the prediction that effective humor production acts as an honest indicator of intelligence in humans. In addition, extraversion, and to a lesser extent, openness, may reflect motivational traits that encourage humor production.
Is a Successful High-K Fitness Strategy Associated with Better Mental Health?
Authors: Giosan Cezar , Wyka Katarzyna
Published: July 2015

This study examined the associations between a high-K fitness strategy and mental health. These associations were tested on a sample of 1400 disaster workers who had exposure to a singular traumatic event and who underwent psychological evaluations. The results showed that high-K was an important negative predictor of psychopathology, accounting for significant variance in PTSD, general psychopathology, functional disability, anger, and sleep disturbances. Implications of the results are discussed.
Dead or Alive? Knowledge about a Sibling's Death Varies by Genetic Relatedness in a Modern Society
Authors: Pollet Thomas V. , Nettle Daniel
Published: July 2015

Using a large sample of non-institutionalized individuals from the Netherlands ( n = 7610), we examined the influence of relatedness on an individual's knowledge about whether their sibling is alive or not. Respondents were generally less likely to know whether their sibling was alive if they were not fully related. The effects were stronger for differences between paternal half-siblings and full siblings than for differences between maternal half-siblings and full siblings.
Differential Investment Behavior between Grandparents and Grandchildren: The Role of Paternity Uncertainty
Authors: Bishop David I. , Meyer Brian C. , Schmidt Tiffany M. , Gray Benjamin R.
Published: July 2015

Kin selection theory predicts that grandparents will differentially invest in their grandchildren as a function of paternity certainty. This study explored the hypothesis of “discriminative grandparental solicitude” ( Euler and Weitzel, 1996 ; Smith, 1988 ) in a sample of college students. Students with four living grandparents were asked to indicate the frequency of various behaviors received from or directed to each grandparent. A significant linear trend on a majority of the measures supported this hypothesis. Reported contact and closeness were highest with the maternal grandmother (most genetically certain) and lowest with the paternal grandfather (least genetically certain); maternal grandfathers and paternal grandmothers were intermediate. The “preferential investment hypothesis” ( Laham, Gonsalkorale, and von Hippel, 2005 ) predicts that the investment behavior of the maternal grandfather and the paternal grandmother should differ only when there are cousins through the father's sisters. Contrary to the predictions of this hypothesis, grandchildren did not rate the maternal grandfather consistently higher on any of the indices when more certain investment outlets were available to the paternal grandmother.
Sex Differences in the Use of Indirect Aggression in Adult Canadians
Authors: Moroschan Gail , Hurd Peter L. , Nicoladis Elena
Published: July 2015

Evolutionary psychologists have argued that the emergence of language was associated with reducing direct physical aggression and easing social functioning in small groups. If this is so, then males should use verbal or indirect aggression more frequently than females since they engage in more direct aggression. A recent study found no significant differences between men and women's self-reports of indirect aggression in a U.K. sample. We administered the same questionnaire to 175 male and 311 female Canadian university students. Men in this population reported using indirect aggression more frequently than women. The Canadian participants generally reported using indirect aggression less frequently than the U.K. study sample did, particularly the women. These results suggest that there are cultural differences in adults' frequency of use of indirect aggression. We review a number of possible reasons to account for these different results.