MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Evolution and Human Behaviour' source. Fri, 12 Mar 2010 15:23:23 +0100 http://www.medworm.com/index.php?rid=3293330&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809001317%2Fabstract%3Frss%3Dyes Pollet and Nettle (; henceforth, P&N) used ordinal regression models to investigate the effect of indicators of male quality, height and income, on self-reported female orgasm frequency. The strategy was as follows: in the first step the two key variables, male height and male income, were included. Subsequently, height was removed as it proved not to be a significant predictor at 5% level. Then, using an information theoretic approach, the authors examined whether model fit could be improved by adding control variables and stopped when the model could not be further improved as assessed by the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC). P&N concluded that the best-fitting model contained partner income as a predictor. (Source: Evolution and Human Behav... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3293330 Mon, 22 Feb 2010 15:45:51 +0100 3293330 http://www.medworm.com/index.php?rid=3293329&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000646%2Fabstract%3Frss%3Dyes In a recent article in this journal (Pollet and Nettle, 2009), we reported that women with higher-income partners reported more frequent orgasms in the data from the Chinese Health and Family Life Survey (CHFLS). We also reported, using a stepwise model selection strategy implemented in SPSS 15.0 (SPSS, Chicago, IL, USA), that partner income was a better predictor of reported orgasm frequency than a number of control variables. However, in an accompanying commentary, Herberich et al. show that the model-fit statistics produced in SPSS are not properly comparable between models. This led us to choose an incorrect model as the best-fitting one. As they show, the effect of partner income is no longer significant once the control variables have been accounted for. We therefore wish to correct ... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3293329 Mon, 22 Feb 2010 15:45:50 +0100 3293329 http://www.medworm.com/index.php?rid=3077786&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809001202%2Fabstract%3Frss%3Dyes Margo Ings Wilson, Professor of Psychology (Source: Evolution and Human Behaviour) Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3077786 Fri, 11 Dec 2009 14:59:13 +0100 3077786 http://www.medworm.com/index.php?rid=3293327&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000853%2Fabstract%3Frss%3Dyes Abstract: The Wason selection task, a standard test of conditional reasoning, has featured prominently in experimental studies of cognitive adaptations for cooperation. The most prominent of these is Cosmides' investigations of cheater detection on social contract versions of the Wason selection task [Cognition 31 (1989) 187–276]. Subsequent to Cosmides' initial investigations, several researchers [Evol Hum Behav 21 (200) 25–37; Manage Decis Econ 19 (1998) 467–480; J Genet Psychol 163 (2002) 425–444; Evol Hum Behav 27 (2006) 366–380] have argued that people also are competent at detecting altruism on the Wason selection task, suggesting that there is nothing privileged about the detection of cheaters. However, an analysis of the selection tasks on which these claims are based sug... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3293327 Fri, 11 Dec 2009 00:00:00 +0100 3293327 http://www.medworm.com/index.php?rid=3293324&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000919%2Fabstract%3Frss%3Dyes Abstract: To test the hypothesis that sensitivity to monitoring drives people to act altruistically toward members of their own community, two experiments investigated whether an eye-like painting promotes altruism toward in-group members, but not toward out-group members. Participants played the role of dictator in a dictator game with another participant (a recipient) who was from the minimal in-group or out-group. Participants knew whether their recipient was an in-group member or an out-group member, but were informed that their recipient did not know the group membership of the dictator. In-group favoritism occurred only when participants were facing a computer desktop which displayed a painting of eyes, but did not occur in the absence of eyes. These findings demonstrate that the eye... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3293324 Wed, 02 Dec 2009 00:00:00 +0100 3293324 http://www.medworm.com/index.php?rid=3077787&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000890%2Fabstract%3Frss%3Dyes In this study, we investigate in a real-life situation, whether (1) the perception of child facial resemblance and (2) the likelihood of parental investment were predicted by actual facial resemblance to self, for both parents. The actual facial resemblance of 79 French children was quantified by testing external judges. Data on ascription of resemblance and parental investment were collected in private for each parent. First, ascription of facial resemblance was found to be consistent between the two parents and to match actual resemblance to the father. Second, emotional closeness as reported by fathers, but not by mothers, was found to be predicted by actual facial resemblance to self. This suggests that paternity uncertainty has favored the use of facial phenotype matching in fathers. ... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3077787 Thu, 19 Nov 2009 00:00:00 +0100 3077787 http://www.medworm.com/index.php?rid=3077794&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000907%2Fabstract%3Frss%3Dyes Abstract: Because women's preferences for male masculinity reflect tradeoffs between the benefits of greater genetic health and the costs of lower paternal investment, variables that affect the importance of these costs and benefits also affect masculinity preferences. Concern about disease and pathogens may be one such variable. Here we show that disgust sensitivity in the pathogen domain is positively correlated with facial masculinity preferences, but disgust sensitivity in the moral and sexual domains is not. Our findings present novel evidence that systematic variation in women's preferences for masculine men reflects factors that influence how women resolve the tradeoff between the benefits and costs associated with choosing a masculine partner. (Source: Evolution and Human Behaviour... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3077794 Wed, 18 Nov 2009 00:00:00 +0100 3077794 http://www.medworm.com/index.php?rid=3293325&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000877%2Fabstract%3Frss%3Dyes Abstract: Several studies have indicated that people are able to memorize the face of a cheater more accurately than that of a noncheater, but some contradictory findings have also been reported. Because most previous studies focused on memory for the faces of cheaters who break social contracts, the consequence for the subjects of their cheating was unclear. In our study, participants were asked to decide whether they trusted persons depicted in photographs to give them money using two sessions of the Faith Game. The participants tended to not increase their trust in the individuals, depicted in photographs, who had altruistically given money to them previously. However, participants recognized nonaltruists who had not shared money and, during the second session, rescinded the trust that ... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3293325 Mon, 16 Nov 2009 00:00:00 +0100 3293325 http://www.medworm.com/index.php?rid=3293326&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000841%2Fabstract%3Frss%3Dyes Abstract: Theoretical work predicts that individuals should strategically increase their reliance on social learning when individual learning would be costly or risky, or when the payoffs for individually learned behaviors are uncertain. Using a method known to elicit cumulative cultural evolution in the laboratory, we investigated the degree of within-group similarity, and between-group variation, in design choices made by participants under conditions of varying uncertainty about the likely effectiveness of those designs. Participants were required to build a tower from spaghetti and modeling clay, their goal being to build the tower as high as possible. In one condition, towers were measured immediately on completion and, therefore, participants were able to judge the success of their d... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3293326 Mon, 09 Nov 2009 00:00:00 +0100 3293326 http://www.medworm.com/index.php?rid=3293321&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000932%2Fabstract%3Frss%3Dyes In this study, we defined cooperators and non-cooperators in terms of their behavior as the proposer in an ultimatum game, and video-taped their facial expressions as they faced unfair offers as a responder. A detailed analysis of the facial expressions displayed by participants revealed that cooperators displayed greater amounts of emotional expressions, not limited to positive emotional expression, when responding to unfair offers in the ultimatum game. These results suggest that cooperators may be more emotionally expressive than non-cooperators. We speculate that emotional expressivity can be a more reliable signal of cooperativeness than the display of positive emotion alone. (Source: Evolution and Human Behaviour) Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3293321 Mon, 09 Nov 2009 00:00:00 +0100 3293321 http://www.medworm.com/index.php?rid=3077792&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS109051380900066X%2Fabstract%3Frss%3Dyes Abstract: It is clear that genes at the major histocompatibility complex (MHC) are involved in mate preferences in a range of species, including humans. However, many questions remain regarding the MHC's exact influence on mate preference in humans. Some research suggests that genetic dissimilarity and individual genetic diversity (heterozygosity) at the MHC influence mate preferences, but the evidence is often inconsistent across studies. In addition, it is not known whether apparent preferences for MHC dissimilarity are specific to the MHC or reflect a more general preference for genome-wide dissimilarity, and whether MHC-related preferences are dependent on the context of mate choice (e.g., when choosing a short-term and long-term partner). Here, we investigated whether preferences for ... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3077792 Mon, 26 Oct 2009 00:00:00 +0100 3077792 http://www.medworm.com/index.php?rid=3293322&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000695%2Fabstract%3Frss%3Dyes Abstract: In the present study, the costly signaling theory (CST) is used to examine the effect of an offer of charity on social recognition. On behalf of a charitable organization, 186 students enrolled in 16 different courses were asked to offer support to unfamiliar persons in need. In accordance with our predictions, the results show that significantly more subjects are willing to give assistance if they make charity offers in the presence of their group members than when the offers are made in secret. In accordance with CST—but not with the prevailing explanations in social psychology—the likelihood of charity service was strongly influenced by the expected cost of altruistic behavior. Publicly demonstrated altruistic intentions yielded long-term benefits: Subjects who were willin... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3293322 Fri, 23 Oct 2009 00:00:00 +0100 3293322 http://www.medworm.com/index.php?rid=3077793&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000816%2Fabstract%3Frss%3Dyes Abstract: Evolutionary explanations of low fertility in modern affluent societies commonly state that low fertility is the outcome of high parental investments in the quality of their children. Although the empirical evidence that modern parents do face a quantity–quality trade-off is strong, two issues that are relevant from an evolutionary perspective have not received much attention. First, sex differences in the proximate aspects of quality have been largely ignored. Second, the relationship between the quantity of children and their reproductive success in contemporary low-fertility societies remains unclear. In this article, we study the quantity–quality trade-off as a trade-off between the number of children and the mate value and reproductive success of those children. We exami... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3077793 Fri, 23 Oct 2009 00:00:00 +0100 3077793 http://www.medworm.com/index.php?rid=2882091&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000804%2Fabstract%3Frss%3Dyes With 2,400 years of hindsight, it seems unlikely that Plato's eternal, immutable Forms actually exist. No one believes, for example, that all chairs are merely shadows cast by a literal, eternal Chair, apprehensible only to the intellect. When it comes to living organisms, however, including Homo sapiens, Plato's concept of Forms still has some traction. Genes, like Forms, are more or less immutable and only indirectly perceptible, yet they appear to encode the essence of what it means to be a human. Because genes vary, they also raise the unsettling specter of distinct African, Asian, and European essences, or natures, a specter that has hobbled investigation of the genetic basis of human behavior for decades. (Source: Evolution and Human Behaviour) Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2882091 Mon, 12 Oct 2009 14:03:51 +0100 2882091 http://www.medworm.com/index.php?rid=3293332&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000920%2Fabstract%3Frss%3Dyes “Are these the Nazis, Walter?”“No, Donny, these men are nihilists, there's nothing to be afraid of.”Dialogue from The Big Lebowski,Generation X and, even more so, the generation following it (those born 1984–2000) have grown up an extremely nihilistic generation. I do not mean nihilistic in the way The Big Lebowski means it (where they care about nothing), but instead in what I believe to be the mantra of nihilism: de omnibus dubitandum (“everything is to be doubted”). Many people associate this saying with Descartes, but I believe it is Nietzsche that understood the real impact of the term.Blog posting from the website “The Christian Watershed” (Source: Evolution and Human Behaviour) Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3293332 Fri, 09 Oct 2009 00:00:00 +0100 3293332 http://www.medworm.com/index.php?rid=3293328&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000683%2Fabstract%3Frss%3Dyes This study tests the folk psychological belief that we find things funny because we think they are true. Specifically, it addresses the relationship between implicit preferences and laughter. Fifty-nine undergraduate Rutgers University students (33 females and 26 males) from ethnically diverse backgrounds were videotaped while watching a white stand-up comedian for 30 min. Positive emotional expression associated with laughter was later scored using the facial action coding system (FACS). Computer-timed Implicit Association Tests (IATs) were used to measure a subject's implicit preferences for traditional gender roles and racial preferences (blacks vs. whites). Results show that participants laughed more in response to jokes that matched their implicit preferences (e.g., those with stronge... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3293328 Mon, 05 Oct 2009 00:00:00 +0100 3293328 http://www.medworm.com/index.php?rid=3293331&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000865%2Fabstract%3Frss%3Dyes It seems these days that female sexuality is one of the hot topics, whether you are a psychologist, biologist, sex researcher, anthropologist, sociologist or feminist. A plethora of books (both academic and popular press) have been published from The Secrets of Female Sexuality: Unapologetic Brutally Honest Truth About Sex That Women Secretly Wish You Knew But Can't Tell You (2007) by David Shade to The Case of The Female Orgasm: Bias in the Science of Evolution (2006) by Elizabeth Lloyd to the soon-to-be-published Why Women Have Sex: Understanding Sexual Motivations From Adventure to Revenge (And Everything in Between) (2009) by Cindy Meston and David Buss. (Source: Evolution and Human Behaviour) Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3293331 Tue, 22 Sep 2009 00:00:00 +0100 3293331 http://www.medworm.com/index.php?rid=3293323&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000701%2Fabstract%3Frss%3Dyes Abstract: Understanding the ultimate and proximate mechanisms that favour cooperation remains one of the greatest challenges in the biological and social sciences. A number of theoretical studies have suggested that competition between groups may have played a key role in the evolution of cooperation within human societies, and similar ideas have been discussed for other organisms, especially cooperative breeding vertebrates. However, there is a relative lack of empirical work testing these ideas. Our experiment found, in public goods games with humans, that when groups competed with other groups for financial rewards, individuals made larger contributions within their own groups. In such situations, participants were more likely to regard their group mates as collaborators rather than com... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3293323 Wed, 16 Sep 2009 00:00:00 +0100 3293323 http://www.medworm.com/index.php?rid=3077795&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS109051380900083X%2Fabstract%3Frss%3Dyes When we think of what behavior, if any, makes us distinctly human—of what do we think? One might be inclined to think of our ability to plan ahead or our complex language, religion, and culture. However, if we look at the most phylogenetically recent structure responsible for generating behavior, the cerebral cortex, we find that the vast majority of ours is dedicated to the interpretation of sensory information, the vast majority of which is dedicated to vision. Oddly, while we have books on the evolution of decision-making, language, religion, and culture, few books on the evolution of visual perception exist. The stated goal of The Vision Revolution is to explain the origin of select visual perception mechanisms. (Source: Evolution and Human Behaviour) Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3077795 Fri, 11 Sep 2009 00:00:00 +0100 3077795 http://www.medworm.com/index.php?rid=3077789&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000592%2Fabstract%3Frss%3Dyes Abstract: Evidence across the social and behavioral sciences points to psychological mechanisms that facilitate the formation and maintenance of interpersonal commitment. In addition, evolutionary simulation studies suggest that a tendency for increased, seemingly irrational commitment is an important trait of successful exchange strategies. However, empirical research that tests corresponding psychological mechanisms is still largely lacking. Here an experimental test is proposed for one such mechanism, termed the commitment bias, which is hypothesized to increase people's commitment to existing partners beyond instrumental reasons. To exclude one alternative explanation, the commitment bias is distinguished from uncertainty reduction. Results from a cross-culturally replicated laboratory... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3077789 Thu, 10 Sep 2009 00:00:00 +0100 3077789 http://www.medworm.com/index.php?rid=3293320&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000622%2Fabstract%3Frss%3Dyes In this study, we tested whether individuals are able to identify altruistic traits. Judges watched 20-s silent video clips of unacquainted target persons and were asked to estimate the behavior of these target persons in a money-sharing task. As the videotapes of the target persons had been recorded in a setting unrelated to altruistic behavior, the judges could not base their estimates on situational cues related to the money-sharing task but instead had to draw on stable signals of altruism. Estimates were significantly better than chance, indicating that individuals can identify permanent altruistic traits in others. As this mechanism raises opportunities for selective interactions between altruists, our findings are discussed with respect to their relevance for explaining the evolutio... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3293320 Wed, 09 Sep 2009 00:00:00 +0100 3293320 http://www.medworm.com/index.php?rid=3077790&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000610%2Fabstract%3Frss%3Dyes Abstract: Previous mate preference studies indicate that people prefer partners whose personalities are extremely kind and trustworthy, but relatively nondominant. This conclusion, however, is based on research that leaves unclear whether these traits describe the behavior a partner directs toward oneself, toward other classes of people or both. Because the fitness consequences of partners' behaviors likely differed depending on the classes of individuals toward whom behaviors were directed, we predicted that mate preferences for personality traits would change depending on the specific targets of a partner's behavioral acts. Consistent with this, two experiments demonstrated that people prefer partners who are extremely kind and trustworthy when considering behaviors directed toward thems... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3077790 Wed, 09 Sep 2009 00:00:00 +0100 3077790 http://www.medworm.com/index.php?rid=3077791&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000634%2Fabstract%3Frss%3Dyes Abstract: Evidence from the anthropological record indicates that in most human societies, parents control the mating access to their offspring. Based on these data, a model of sexual selection has been recently proposed, whereby along with female and male choice, parental choice constitutes a significant sexual selection force in our species. This model was found to provide a good account for the mating patterns which are typical of foraging societies. By employing data from the Standard Cross Cultural Sample, the present study aims at examining whether this model can also account for the mating patterns typical of agricultural and pastoral societies. In addition, comparisons between different society types are made and two model-derived hypotheses are tested. First, it is hypothesised th... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3077791 Mon, 07 Sep 2009 00:00:00 +0100 3077791 http://www.medworm.com/index.php?rid=2882090&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000609%2Fabstract%3Frss%3Dyes This study investigated sex-specific predictors of violent and nonviolent mate guarding used by men (n=399) and women (n=951) in heterosexual relationships, using both self-reports and reports on partners. We found, contrary to some previous evolutionary assumptions, that men and women showed similar degrees of controlling behavior, and that this predicted physical aggression to partners in both sexes. We also predicted from evolutionarily based studies that men's and women's control and aggression would vary as a function of female fecundity and mate value (relative to peer group and to partner). Fecundity was associated with men's and women's controlling behavior, but not their physical aggression: relationships where the woman was fecund showed higher rates of control. According to part... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2882090 Sun, 06 Sep 2009 23:00:00 +0100 2882090 http://www.medworm.com/index.php?rid=2882089&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000555%2Fabstract%3Frss%3Dyes Abstract: Previous studies with adult humans and nonhuman animals revealed more rapid fear learning for spiders and snakes than for mushrooms and flowers. The current experiments tested whether 11-month-olds show a similar effect in learning associative pairings between facial emotions and fear-relevant and fear-irrelevant stimuli. Consistent with the greater incidence of snake and spider phobias in women, results show that female but not male infants learn rapidly to associate negative facial emotions with fear-relevant stimuli. No difference was found between the sexes for fear-irrelevant stimuli. The results are discussed in relation to fear learning, phobias, and a specialized evolved fear mechanism in humans. (Source: Evolution and Human Behaviour) Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2882089 Sun, 16 Aug 2009 23:00:00 +0100 2882089 http://www.medworm.com/index.php?rid=2882086&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000580%2Fabstract%3Frss%3Dyes In this study, we assessed the relative importance of the face and body in judgments of human physical attractiveness. One hundred twenty-seven men and 133 women were shown images of 10 individuals of the opposite sex. Participants rated the images for their attractiveness for either a short-term relationship or a long-term relationship. Images of the face and the body were rated independently before participants were shown and asked to rate the combined face and body images. Face ratings were found to be the best predictor of the ratings of combined images for both sexes and for both relationship types. Females showed no difference in ratings between short- and long-term conditions, but male ratings of female bodies became relatively more important for a short-term relationship compared w... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2882086 Sun, 16 Aug 2009 23:00:00 +0100 2882086 http://www.medworm.com/index.php?rid=2882085&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000579%2Fabstract%3Frss%3Dyes Abstract: Attractiveness judgments are thought to underpin adaptive mate choice decisions. We investigated how these judgments change during adolescence when mate choice is becoming relevant. Adolescents aged 11–15 evaluated faces and voices manipulated along dimensions that affect adults' judgments of attractiveness and that are thought to cue mate value. Facial stimuli consisted of pairs of faces that were more or less average, more or less feminine, or more or less symmetric. The adolescents selected the more average, symmetric, and feminine faces as more attractive more often than chance, but judgments of some facial traits differed significantly with rater age and sex, indicating a role of development in judgments of facial cues. Vocal stimuli consisted of pairs of voices manipulate... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2882085 Sun, 16 Aug 2009 23:00:00 +0100 2882085 http://www.medworm.com/index.php?rid=2882084&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000567%2Fabstract%3Frss%3Dyes Abstract: Recent studies show that subtle cues of observation affect cooperation even when anonymity is explicitly assured. For instance, recent studies have shown that the presence of eyes increases cooperation on social economic tasks. Here, we tested the effects of cues of observation on trusting behavior in a two-player Trust game and the extent to which these effects are qualified by participants' own attractiveness. Although explicit cues of being observed (i.e., when participants were informed that the other player would see their face) tended to increase trusting behavior, this effect was qualified by the participants' other-rated attractiveness (estimated from third-party ratings of face photographs). Participants' own physical attractiveness was positively correlated with the ext... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2882084 Sun, 16 Aug 2009 23:00:00 +0100 2882084 http://www.medworm.com/index.php?rid=2882083&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000439%2Fabstract%3Frss%3Dyes Abstract: A crucially important aspect of human cooperation is the ability to negotiate to cooperative outcomes when interests over resources conflict. Although chimpanzees and other social species may negotiate conflicting interests regarding travel direction or activity timing, very little is known about their ability to negotiate conflicting preferences over food. In the current study, we presented pairs of chimpanzees with a choice between two cooperative tasks—one with equal payoffs (e.g., 5-5) and one with unequal payoffs (higher and lower than in the equal option, e.g., 10-1). This created a conflict of interests between partners with failure to work together on the same cooperative task resulting in no payoff for either partner. The chimpanzee pairs cooperated successfully in as ... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2882083 Thu, 06 Aug 2009 23:00:00 +0100 2882083 http://www.medworm.com/index.php?rid=3077788&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000531%2Fabstract%3Frss%3Dyes Abstract: Neonatal features in the newborn are thought to trigger parental care, the most fundamental prosocial behaviour. The underlying mechanisms that release parental care have not yet been resolved. Here we report sex differences in the ability to discriminate cues to cuteness despite equivalence in the capability to discriminate age and facial expression. These differences become apparent in a task where adults were asked to choose the cuter of two babies. While women could reliably choose the cuter infant, men had more difficulty in doing so. When showing the exact same face pairs but asking to choose the younger or the happier baby, there was no sex difference. These results suggest that the sex difference in the ability to discriminate cues to cuteness in infants underlies female-... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=3077788 Thu, 06 Aug 2009 00:00:00 +0100 3077788 http://www.medworm.com/index.php?rid=2882088&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000543%2Fabstract%3Frss%3Dyes Abstract: It has been proposed that a common cause underlies individual differences in bodily and cognitive decline in old age. No good marker for this common cause has been identified to date. Here, fluctuating asymmetry (FA), an indicator of developmental stability that relates to intelligence differences in young adults, was measured from facial photographs of 216 surviving members of the Lothian Birth Cohort 1921 at age 83 and related to their intelligence at ages 11, 79 and 83 years. FA at age 83 was unrelated to intelligence at ages 11 and 79 and to cognitive change between 11 and 79 years. It was, however, associated with intelligence and information processing efficiency at age 83 and with cognitive change between 79 and 83 years. Significant results were limited to men, a result p... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2882088 Wed, 05 Aug 2009 23:00:00 +0100 2882088 http://www.medworm.com/index.php?rid=2882087&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000403%2Fabstract%3Frss%3Dyes Abstract: Behavioural studies of the perceptual cues for female physical attractiveness have suggested two potentially important features: body fat distribution [the waist-to-hip ratio (WHR)] and overall body fat [often estimated by the body mass index (BMI)]. However, none of these studies tell us directly which regions of the stimulus images inform observers' judgments. Therefore, we recorded the eye movements of three groups of 10 male observers and three groups of 10 female observers, when they rated a set of 46 photographs of female bodies. The first sets of observers rated the images for attractiveness, the second sets rated for body fat and the third sets for WHR. If either WHR and/or body fat is used to judge attractiveness, then observers rating attractiveness should look at those... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2882087 Sun, 21 Jun 2009 23:00:00 +0100 2882087 http://www.medworm.com/index.php?rid=2686830&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000427%2Fabstract%3Frss%3Dyes Abstract: The study tested the proposition that relationship involvement influences the implicit responses of women to high- and low-status professions. It was hypothesized that when a high-involvement context was primed, women would have more positive implicit associations with high-status occupations than when a low-involvement context was primed. In contrast, when a high-involvement context was primed, women would have more negative associations with low-status occupations than when a low-involvement context was primed. To test the hypothesis, 123 female participants received a high or low relationship involvement prime. Then the participants completed a single category implicit associations test designed to measure the participants' associations with either high- or low-status occupati... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2686830 Sun, 21 Jun 2009 23:00:00 +0100 2686830 http://www.medworm.com/index.php?rid=2686833&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000415%2Fabstract%3Frss%3Dyes Forensic psychology is generally defined as the application of psychology to the law. The term refers to the testimony a psychologist may give in open court, together with case-specific preparations for such testimony. Evolutionary psychologists will naturally expect Darwinian foundations to improve forensic psychology, and the book is meant to be the first step toward that end. (Source: Evolution and Human Behaviour) Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2686833 Sun, 14 Jun 2009 23:00:00 +0100 2686833 http://www.medworm.com/index.php?rid=2686826&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000397%2Fabstract%3Frss%3Dyes Abstract: On average, men have 61% more muscle mass than women (d=3), a sex difference which is developmentally related to their much higher levels of testosterone. Potential benefits of greater male muscle mass include increased mating opportunities, while potential costs include increased dietary requirements and decreased immune function. Using data on males aged 18–59 years from the third National Health and Nutrition Examination Survey and including other relevant variables, fat-free mass (FFM) and/or limb muscle volume (LMV) are significant predictors of the numbers of total and past-year self-reported sex partners, as well as age at first intercourse. On the cost side, FFM and LMV are strong positive predictors of daily energy intake and strong negative predictors of C-reactive pr... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2686826 Sun, 24 May 2009 23:00:00 +0100 2686826 http://www.medworm.com/index.php?rid=2482245&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000385%2Fabstract%3Frss%3Dyes In The Caveman Mystique (TCM), Martha McCaughey examines how evolutionary accounts of human sexuality circulate in popular culture and influence the ways that men form their ideas of how men should think and act. She goes on to critique evolutionary perspectives on human sexuality. After briefly reviewing the major claims of the book, we clarify misunderstandings of evolutionary perspectives presented and address what we see as valid criticisms of the ways that evolutionary research is sometimes generated and disseminated into popular culture. (Source: Evolution and Human Behaviour) Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2482245 Tue, 12 May 2009 04:00:00 +0100 2482245 http://www.medworm.com/index.php?rid=2482244&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000245%2Fabstract%3Frss%3Dyes Abstract: This paper lays out an evolutionary theory for the cognitive foundations and cultural emergence of the extravagant displays (e.g., ritual mutilation, animal sacrifice and martyrdom) that have so tantalized social scientists, as well as more mundane actions that influence cultural learning and historical processes. In Part I, I use the logic of natural selection to build a theory for how and why seemingly costly displays influence the cognitive processes associated with cultural learning — why do “actions speak louder than words?” The core idea is that cultural learners can both avoid being manipulated by their models (those they are inclined to learn from) and more accurately assess their belief commitment by attending to displays or actions by the model that would seem cos... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2482244 Tue, 12 May 2009 04:00:00 +0100 2482244 http://www.medworm.com/index.php?rid=2482243&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000208%2Fabstract%3Frss%3Dyes We examined whether this male-specific “coalitional psychology” represents in-group love or out-group hate. One hundred thirty-three college freshmen played a prisoner's dilemma game with a member of their own group and a member of another group. Both groups consisted of same-sex participants. An in-group bias (cooperation with the in-group at a level higher than cooperation with the out-group) based on expectations of cooperation from the in-group was observed for both men and women. When such expectations were experimentally eliminated, women did not show any in-group bias, whereas men still exhibited an in-group bias. This male-specific in-group bias was found to be a product of intragroup cooperation (in-group love) rather than a product of intergroup competition (out-group hate). ... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2482243 Tue, 12 May 2009 04:00:00 +0100 2482243 http://www.medworm.com/index.php?rid=2686832&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000221%2Fabstract%3Frss%3Dyes Abstract: Handedness is a product of brain specialization, which in turn seems to be responsible for the higher cognitive capabilities of humans, such as language and technology. Handedness in living humans is well established and shows the highest degree of manual specialization. Studies on hand laterality in nonhuman primates, particularly in chimpanzees, remain a matter of controversy as results tend to vary depending on factors such as the tasks performed and the environment in which the individuals live. Studies in several disciplines have attempted to determine where in the course of human evolution handedness established itself, with evidence collected from sources such as paleoneurological analyses, stone tool flaking, zooarchaeological studies and dental wear analyses, the last on... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2686832 Mon, 11 May 2009 23:00:00 +0100 2686832 http://www.medworm.com/index.php?rid=2686828&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000270%2Fabstract%3Frss%3Dyes Abstract: Physical attractiveness has been associated with mating behavior, but its role in reproductive success of contemporary humans has received surprisingly little attention. In the Wisconsin Longitudinal Study (1244 women, 997 men born between 1937 and 1940), we examined whether attractiveness assessed from photographs taken at age ∼18 years predicted the number of biological children at age 53–56 years. In women, attractiveness predicted higher reproductive success in a nonlinear fashion, so that attractive (second highest quartile) women had 16% and very attractive (highest quartile) women 6% more children than their less attractive counterparts. In men, there was a threshold effect so that men in the lowest attractiveness quartile had 13% fewer children than others who did not... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2686828 Mon, 11 May 2009 23:00:00 +0100 2686828 http://www.medworm.com/index.php?rid=2686827&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000282%2Fabstract%3Frss%3Dyes Abstract: Studying biological and social determinants of mortality and fertility provides insight into selective pressures in a population and the possibility of trade-offs between short- and long-term reproductive success. Limited data is available from post-demographic transition populations. We studied determinants of reproductive success using multi-generational data from a large, population-based cohort of 13,666 individuals born in Sweden between 1915 and 1929. We studied the effects of birthweight for gestational age, preterm birth, birth multiplicity, birth order, mother's age, mother's marital status and family socioeconomic position (SEP) upon reproductive success, measured as total number of children and grandchildren. We further tested the hypothesis that number of grandchildre... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2686827 Mon, 11 May 2009 23:00:00 +0100 2686827 http://www.medworm.com/index.php?rid=2686829&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000269%2Fabstract%3Frss%3Dyes Abstract: Previous research has demonstrated that female behaviors toward men or sexual interest are different across the menstrual cycle. However, women's receptivity to an explicit courtship solicitation still remained in question. In a field experiment, 20-year-old women were approached by 20-year-old male confederates in nightclubs and solicited to dance during the period when slow songs were played. A survey was administered to the women in order to obtain information about the number of days since the onset of previous menses. It was found that women in their fertile phase agreed more favorably to the dance request than women in their luteal phase or in their menstrual phase. (Source: Evolution and Human Behaviour) Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2686829 Tue, 21 Apr 2009 23:00:00 +0100 2686829 http://www.medworm.com/index.php?rid=2686825&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000257%2Fabstract%3Frss%3Dyes This study extends previous ones showing a link between direct aggression and size and strength among young men, which were informed by the evolutionary concept of resource holding power (RHP), using measures of size, strength, flexed bicep circumference and hand grip strength among a sample of young men from the Indian state of Mizoram. The study also examined the relation of these variables to reactive and proactive aggression, to entitlement to resources (related to the threatened egotism theory of aggression) and mate value (central to a modular theory of self-esteem and more broadly to sexual selection). The findings showed only a weak association between size and strength and direct aggression, which was also significantly correlated with entitlement and mate value, as predicted. Mat... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2686825 Tue, 21 Apr 2009 23:00:00 +0100 2686825 http://www.medworm.com/index.php?rid=2494676&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000233%2Fabstract%3Frss%3Dyes Abstract: It is often assumed that parent-to-child cultural transmission leads to similarities and differences among groups evolving through descent with modification (“phylogenesis”). Similarly, cultural transmission between peers, and between adults and children who are not their offspring, is widely believed to result in groups exchanging cultural traits (“ethnogenesis”). However, neither of these assumptions has been examined empirically. Here, we test them using ethnographic data on craft learning in Iranian tribal populations and the cladistic method of phylogenetic analysis. We find that parent-to-child transmission dominates learning during childhood, but the other two forms of interindividual transmission become more important in later periods. The latter do not, however, ... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2494676 Tue, 21 Apr 2009 23:00:00 +0100 2494676 http://www.medworm.com/index.php?rid=2494674&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000191%2Fabstract%3Frss%3Dyes Abstract: Why do societies collapse? We use an individual-based evolutionary model to show that, in environmental conditions dominated by low-frequency variation (“red noise”), extirpation may be an outcome of the evolution of cultural capacity. Previous analytical models predicted an equilibrium between individual learners and social learners, or a contingent strategy in which individuals learn socially or individually depending on the circumstances. However, in red noise environments, whose main signature is that variation is concentrated in relatively large, relatively rare excursions, individual learning may be selected from the population. If the social learning system comes to lack sufficient individual learning or cognitively costly adaptive biases, behavior ceases tracking envi... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2494674 Tue, 21 Apr 2009 23:00:00 +0100 2494674 http://www.medworm.com/index.php?rid=2351995&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000130%2Fabstract%3Frss%3Dyes The idea that “religion” may have evolved through Darwinian selection has seen an explosion of interest recently, giving rise to numerous journal articles, dedicated conferences and books (for reviews, see ). The field offers a treasure trove for scholars of human evolution because it spans so many topics of interest to us. First of all, there are important theoretical and empirical questions at each of Tinbergen's four levels of analysis: What is its evolutionary function? What are the proximate mechanisms? What are its developmental features? What is its phylogeny in the human lineage? It also confronts other areas of importance, including the evolution of cooperation, maladaptive behavior in modern life, levels of selection (individual vs. group selection) and multiple possible evol... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2351995 Tue, 21 Apr 2009 21:43:22 +0100 2351995 http://www.medworm.com/index.php?rid=2351994&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000154%2Fabstract%3Frss%3Dyes Abstract: Previous studies sought to test for the existence of a “cheater-detection module” by testing for enhanced memory for the faces of cheaters, but past results have been inconclusive. Here, we present four experiments showing that old–new discrimination was not affected by whether a face was associated with a history of cheating, trustworthy or irrelevant behavior. In contrast, source memory for faces associated with a history of cheating (i.e., memory for the cheating context in which the face was encountered) was consistently better than source memory for other types of faces. This pattern held under a variety of conditions, including different types of judgments participants made about the stimulus persons (attractiveness in Experiment 1; likeability in Experiments 2–4), ... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2351994 Tue, 21 Apr 2009 21:43:17 +0100 2351994 http://www.medworm.com/index.php?rid=2351993&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000142%2Fabstract%3Frss%3Dyes This study examines the effects of ingroup favoritism and outgroup hostility (“parochialism”), as well as of conditionally cooperative strategies, in explaining contributions to experimental public goods games. The experimental conditions vary group composition along two culturally inheritable traits (political party preference and religious affiliation) and one trivial, “minimal” trait (birth season). We contrast ingroup, outgroup, and random group conditions and investigate the relation between the own contribution to the public good and the expectations about other group members' behavior in each one of them. We find evidence for ingroup favoritism but no support for a separate tendency towards outgroup hostility. Further, conditional cooperation and ingroup bias are, to some ex... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2351993 Tue, 21 Apr 2009 21:43:16 +0100 2351993 http://www.medworm.com/index.php?rid=2351992&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000026%2Fabstract%3Frss%3Dyes Abstract: Prosociality is a fundamental theme in all branches of the human behavioral sciences. Evolutionary theory sets an even broader stage by examining prosociality in all species, including the distinctive human capacity to cooperate in large groups of unrelated individuals. We use evolutionary theory to investigate human prosociality at the scale of a small city (Binghamton, NY), based on survey data and a direct measure of prosocial behavior. In a survey of public school students (Grades 6–12), individual prosociality correlates strongly with social support, which is a basic requirement for prosociality to succeed as a behavioral strategy in Darwinian terms. The most prosocial individuals receive social support from multiple sources (e.g., family, school, neighborhood, religion an... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2351992 Tue, 21 Apr 2009 21:43:14 +0100 2351992 http://www.medworm.com/index.php?rid=2351991&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000038%2Fabstract%3Frss%3Dyes Abstract: Stepchildren are abused, neglected and murdered at higher rates than those who live with two genetically related parents. Daly and Wilson used kin selection theory to explain this finding and labeled the phenomenon “discriminative parental solicitude.” I examined discriminative parental solicitude in American households composed of both genetic and unrelated adopted children. In these families, kin selection predicts parents should favor their genetic children over adoptees. Rather than looking at cases of abuse, neglect, homicide and other antisocial behavior, I focused on the positive investments parents made in their children as well as the outcomes of each child. The results show that parents invested more in adopted children than in genetically related ones, especially i... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2351991 Tue, 21 Apr 2009 21:43:06 +0100 2351991 http://www.medworm.com/index.php?rid=2351990&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513808001220%2Fabstract%3Frss%3Dyes Abstract: Evolutionary and economic models of the family propose that parents face a fundamental trade-off between fertility and investment per offspring. However, tests of this hypothesis have focused primarily on offspring outcomes rather than direct measures of parental investment. Existing studies of parenting also suffer a number of methodological problems now recognized as common sources of error in sociodemographic studies. Here, we present a more definitive picture of the effects of family structure on parental care by analyzing an extensive longitudinal dataset of contemporary British families (the Avon Longitudinal Study of Parents and Children). Unlike other studies, we simultaneously track maternal and paternal behaviors within the same family and consider variation both across... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2351990 Tue, 21 Apr 2009 21:42:49 +0100 2351990 http://www.medworm.com/index.php?rid=2351989&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513808001219%2Fabstract%3Frss%3Dyes Abstract: The hot hand phenomenon refers to the expectation of “streaks” in sequences of hits and misses whose probabilities are, in fact, independent (e.g., coin tosses, basketball shots). Here we propose that the hot hand phenomenon reflects an evolved psychological assumption that items in the world come in clumps, and that hot hand, not randomness, is our evolved psychological default. In two experiments, American undergraduates and Shuar hunter–horticulturalists participated in computer tasks in which they predicted hits and misses in foraging for fruits, coin tosses, and several other kinds of resources whose distributions were generated randomly. Subjects in both populations exhibited the hot hand assumption across all the resource types. The only exception was for American st... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2351989 Tue, 21 Apr 2009 21:42:38 +0100 2351989 http://www.medworm.com/index.php?rid=2351988&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513808001189%2Fabstract%3Frss%3Dyes Abstract: Natural experiments such as the Israeli Kibbutzim and Taiwanese minor marriages provide unique opportunities for testing the effects of childhood association on adult sexual attraction. Within these populations, early childhood association leads to the development of a sexual aversion, an effect first proposed by Edward Westermarck. However, recent analysis of Taiwanese minor marriages indicates that only the age at first association (an inverse index of childhood association) of the younger partner predicts marital fertility rates; the age at first association of the older partner does not. Although considered a puzzle, a recent model of human inbreeding avoidance can explain this pattern. This model suggests that the mind uses at least two kinship cues to regulate the developme... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2351988 Tue, 21 Apr 2009 21:42:25 +0100 2351988 http://www.medworm.com/index.php?rid=2686824&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000166%2Fabstract%3Frss%3Dyes Abstract: In this article, I present evidence for a robust and quite general force of selection on the human life cycle. The force of selection acts in remarkably invariant ways on human life histories, despite a great abundance of demographic diversity. Human life histories are highly structured, with mortality and fertility changing substantially through the life cycle. This structure necessitates the use of structured population models to understand human life history evolution. Using such structured models, I find that the vital rates to which fitness is most sensitive are prereproductive survival probabilities, particularly the survival of children ages 0 to 4 years. The fact that the preponderance of selection falls on transitions related to recruitment combined with the late age at ... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2686824 Sun, 12 Apr 2009 23:00:00 +0100 2686824 http://www.medworm.com/index.php?rid=2494675&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS1090513809000178%2Fabstract%3Frss%3Dyes Abstract: The modeling of cultural transmission is of great importance for understanding the maintenance, erosion, and spread of cultural traits and innovations. Researchers have hypothesized that, unlike biological transmission, cultural transmission occurs through at least three different, non-mutually exclusive paths: (1) from parents (vertical); (2) from age peers (horizontal); and (3) from older generations (oblique). We used data from 270 adults in a society in the Bolivian Amazon to estimate the association between a person's knowledge and skills and the knowledge and skills of the (1) same-sex parent, (2) age peers (or individuals born in the same village as the subject within ±4 years of the subject's year of birth), and (3) parental cohort (excluding parents). We found a statist... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2494675 Sun, 12 Apr 2009 23:00:00 +0100 2494675 http://www.medworm.com/index.php?rid=2494673&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS109051380900018X%2Fabstract%3Frss%3Dyes Abstract: Intergroup conflict poses a different kind of threat for men and women — a difference that can be expected to have implications for cognitive as well as behavioral processes. Participants were primed with a threat from a rival coalition vs. a control condition. Reaction times were measured on a lexical-decision task in response to ideation consistent with coalitions or with friendship/protective care. When primed for coalitional threat, men showed fast access to positive coalitional ideation (suggesting facilitation). In contrast, women showed exceptionally fast access to positive friendship/protective care ideation. Findings were interpreted as reflecting sexually dimorphic responses to coalitional threat that are consistent with differential advertising of their assets to oth... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2494673 Sun, 12 Apr 2009 23:00:00 +0100 2494673 http://www.medworm.com/index.php?rid=2686831&cid=s_38471_36_f&fid=38471&url=http%3A%2F%2Fwww.ehbonline.org%2Farticle%2FPIIS109051380900021X%2Fabstract%3Frss%3Dyes In this study, we examined whether more frequent or recent illness might act to reverse this process. To test this, we surveyed 616 adults, obtaining illness frequency and recency data, disgust and contamination sensitivity, and a variety of control measures. Heightened contamination sensitivity was associated with more frequent infectious illness, but not with recency of infection. We also found that participants who had heightened contamination sensitivity and who were also more disgust sensitive had significantly fewer recent infections. These findings suggest that frequent illness may up-regulate contamination sensitivity potentially counteracting the effects of exposure on disgust. More importantly, these data provide the first direct evidence of a protective effect of contamination a... Evolution and Human Behaviour journals http://www.medworm.com/rss/comments.php?id=2686831 Sun, 05 Apr 2009 23:00:00 +0100 2686831