Evolution & Human Behavior - Articles in Press

Dishonesty invites costly third-party punishment - Corrected Proof

Yohsuke Ohtsubo, Fumiko Masuda, Esuka Watanabe, Ayumi Masuchi — 2010-02-26

Abstract: Third-party punishment for norm violators is an evolvable enforcer of social norms. The present study, involving two experiments, examined whether violations of honesty norms would induce costly third-party punishments. In both experiments, participants in the third-party role observed a protocol of the trust game, in which the trustee solicited the trustor to transfer his/her endowment by stating that the trustee would return x units from the total resource. Dishonesty was defined such that the trustee in fact returned fewer than x units. Participants were asked about their willingness to incur some cost to reduce the trustee's payoff. In Experiment 1, x was exactly half of the total resource. Participants were willing to incur more cost to punish the dishonest trustee than the trustee who allocated the resource unequally but had not sent the dishonest message. In Experiment 2, x was more than half of the total resource and the dishonest trustee allocated the total resource equally. Therefore, the dishonest trustee was not unfair in Experiment 2. Approximately half of the participants (16 of 30) punished the dishonest but fair trustee, while few participants (1 of 30) punished the fair trustee who had not sent the dishonest message. These experiments together demonstrated that participants were willing to incur some cost to punish honesty-norm violators, even when the participants themselves were not harmed by the norm violation.

Corrected Proof

Gregory Gorelik, Todd K. Shackelford — 2010-02-24

Richard Dawkins's The Greatest Show on Earth: The Evidence for Evolution is not only an elegant exposition of the evidence for the scientific fact of evolution, but also a clear and creative explanation of the theory, and the stumbling blocks to its proper understanding. Theory should not be confused with hypothesis, and Dawkins is adamant about referring to evolution as a fact. We agree with him. When scientists and evolutionary scholars refer to “evolutionary theory” among themselves, there is no need to explain that a scientific theory is a framework that describes and predicts processes in the physical world based on mutually supportive, empirical evidence. Outside of scientific circles, however, scientists should be cautious when using the term theory, because antiscientific interests are eager to confuse theory with guess. There is more than enough evidence to cement evolution as a fact — more evidence than there is for other commonly accepted facts. Thus, it is logical to refer to evolution as both a scientific theory and an uncontestable fact. Dawkins plays wordsmith by borrowing the mathematical term theorem, to coin “theorum.” He suggests that scientists might use “theorum” in lieu of the more pernicious “theory” when referring to scientific laws and facts that no rational individual would deny, such as the heliocentric theory of the solar system, the theory of gravity and the theory of evolution.

Why Women Have Sex - Corrected Proof

Jill M. Sundie — 2010-02-04

Sex is serious business. It significantly affects most adults' quality of life and well-being, and can cement or fracture the most intimate of social relationships. Sexual stimuli are so effective at capturing people's attention that in my field of marketing they are used daily to encourage people to purchase an array of products and services such as computing servers, submarine sandwiches, toilet paper, many other things seemingly unrelated to sex. A Google search of the well-known phrase “sex sells” returns over 693,000 hits.

A thin slice of violence: distinguishing violent from nonviolent sex offenders at a glance - Corrected Proof

Tyler F. Stillman, Jon K. Maner, Roy F. Baumeister — 2010-02-04

Abstract: A growing body of literature in evolutionary psychology suggests that person perception processes are adaptively tuned. The current investigation tested the hypothesis that people would be able to detect a propensity for violence in other people, based only on a brief glance at their face. Participants estimated the propensity for violence in 87 registered sex offenders after seeing photos of them for 2 s each. Estimated likelihood of violence was significantly related to actual violent history, suggesting that violent tendencies can be accurately inferred from a brief look at a person's face. Cues indicative of high masculinity and high levels of male sex hormones (heavy brow, general facial masculinity, high physical strength, younger age) were related to accurate judgments. Other cues such as facial emotion and good grooming were not associated with an actual history of violence, but nevertheless correlated with raters' judgments. Although there were no sex differences in accuracy, on average women thought targets were more violent than men did. Findings speak to the accuracy and efficiency with which people can detect potential threats to physical well-being.

Heavy hearts and heads held high — A review of Glimpses of Creatures in Their Physical Worlds - Corrected Proof

Peter DeScioli — 2010-02-04

Glimpses of Creatures in Their Physical Worlds is a heart-pounding, heat-conducting, power-amplifying whirlwind tour through the mechanical and thermal worlds of Earth's living things. The journey has something for everyone: the thrills of explosively launched projectiles, the chills of supercooling polar fish, the rise of birds soaring on an ascending torus of ground-heated air. Along the way, there are insights into the functional analysis of biological systems, relevant not only to researchers in biomechanics but also to the broad community of scientists seeking to understand the workings of life's devices.

Cooperative pastoral production — the importance of kinship - Corrected Proof

Marius Warg Næss, Bård-Jørgen Bårdsen, Per Fauchald, Torkild Tveraa — 2010-02-04

Abstract: While there is a general assumption that labour has a positive effect on pastoral production, studies that have quantified this relationship have been characterized by ambiguous results. This is most likely related to the fact that possible cooperative pastoral production has been little explored in the literature, although it is well documented that nomadic pastoralist households share and exchange labour in so-called cooperative herding groups. Consequently, this study aims at investigating possible cooperative labour-related effects on production among Saami reindeer herders in Norway by using kinship relations as a proxy for cooperation. This study found that cooperative labour investment is important for Saami reindeer herders, but that the effect of kinship and labour needs to be understood in relation to each other. When assessing the effect of labour and kinship simultaneously, both labour and genealogical relationship had positive effects on herd size. We also found a positive interaction between kinship and labour suggesting that high levels of relatedness coupled with a large potential labour pool had an increasingly positive effect on herd size.

Corrected Proof

Terence C. Burnham — 2009-12-09

In Spent, Geoff Miller brings an evolutionary perspective to consumer behavior in modern industrialized societies. The puzzle is the empty and energetic pursuit of materialistic goals. Why do we work so hard to buy goods and services that rarely produce lasting satisfaction?

Blind men prefer a low waist-to-hip ratio - Corrected Proof

Johan C. Karremans, Willem E. Frankenhuis, Sander Arons — 2009-12-09

Abstract: Previous studies suggest that men in Western societies are attracted to low female waist-to-hip ratios (WHR). Several explanations of this preference rely on the importance of visual input for the development of the preference, including explanations stressing the role of visual media. We report evidence showing that congenitally blind men, without previous visual experience, exhibit a preference for low female WHRs when assessing female body shapes through touch, as do their sighted counterparts. This finding shows that a preference for low WHR can develop in the complete absence of visual input and, hence, that such input is not necessary for the preference to develop. However, the strength of the preference was greater for the sighted than the blind men, suggesting that visual input might play a role in reinforcing the preference. These results have implications for debates concerning the evolutionary and developmental origins of human mate preferences, in particular, regarding the role of visual media in shaping such preferences.

Male traits associated with attractiveness in Conambo, Ecuador - Corrected Proof

Michelle Escasa, Peter B. Gray, John Q. Patton — 2009-12-02

Abstract: This study investigated male attractiveness rankings in a small-scale Amazonian society. In the rural community of Conambo, Ecuador, men and women practice self-sufficient horticulture, men hunt, and, traditionally, men have experienced a high rate of mortality due to homicide. We tested whether male attractiveness rankings would be related to male age, warriorship, hunting ability, status, coalitional affiliation, and female age. Twenty-five women aged between 14 and 78 years ranked photographs of 29 local men aged between 16 and 74 years for attractiveness in addition to warriorship, hunting ability, and status. Results revealed that male age was negatively correlated (r=−.683, p=.01) with female rankings of male attractiveness. Warriorship (r=.517, p=.005), status (r=.489, p=.008), and hunting ability (r=.577, p=.001) were found to be positively correlated with attractiveness, after controlling for age. Additionally, females showed a bias for males in their in-group when ranking attractiveness (one-sample t test: T29=16.727, p<.001). Attention is given to male age and coalitional affiliation as factors important in attractiveness rankings; warriorship and hunting ability also serve as ecologically salient features of male social worth. These findings contribute to a broader understanding of human attractiveness research by adding a new case study to the literature that documents previously unreported findings from a cultural context that is significantly different from the standard university-level student sample.

Tattoo and piercing as signals of biological quality - Corrected Proof

Slawomir Koziel, Weronika Kretschmer, Boguslaw Pawlowski — 2009-12-02

Abstract: Tattoos and non-conventional piercings are used in many societies. There are several social reasons for which people use these forms of body decorations (e.g., marking social status or signaling membership within a subculture). However, it is interesting why only some people within a group that uses body decoration as a badge of membership decide upon such decorations. Since both tattoos and piercings can present health risks (e.g., due to blood-borne disease transmission risk), we postulate that people who decide to have such a body decoration might have relatively higher biological quality and that tattoos/piercings can be an honest signal of genetic quality. The possible opposite hypothesis is the “attractiveness increase hypothesis,” according to which people use body decorations to increase their own physical attractiveness or to hide some shortcomings in their appearance (e.g., low body symmetry). To test these hypotheses, we compared body fluctuating asymmetry, which is considered a good measure of developmental stability, between individuals wearing tattoos and/or non-conventional piercings (n=116) and a control group (without such body decorations) (n=86). We found that majority of the absolute and relative fluctuating asymmetry indices had significantly lower values in individuals with tattoos/piercings than in the control group. This effect was strongly driven by males. Higher body symmetry of the men having tattoo or piercing indicates that this type of body decoration in the western society can be related to the honest signal of biological quality only for men. We did not find support for the “attractiveness increase hypothesis” for either sex.

Hormonal responses differ when playing violent video games against an ingroup and outgroup - Corrected Proof

Jonathan Oxford, Davidé Ponzi, David C. Geary — 2009-09-16

Abstract: For 14 teams of three young men, salivary testosterone and cortisol were assessed twice before and twice after competing in within-group and between-group video games that simulated violent male–male competition. Men who contributed the most to their teams' between-group victory showed testosterone increases immediately after the competition, but only if this competition was played before the within-group tournament. High-scoring men on losing teams did not show this immediate effect, but they did show a delayed increase in testosterone. In contrast, high-ranking men tended to have lower testosterone and higher cortisol during within-group tournaments. The results are consistent with the hypothesis that men's competitive testosterone response varies across ingroup and outgroup competitions and is muted during the former. The testosterone response during the between-group competition also suggests that violent multiplayer video games may be appealing to young men because they simulate male–male coalitional competition.

Currency value moderates equity preference among young children - Corrected Proof

Peter R. Blake, David G. Rand — 2009-09-10

Abstract: Cooperative behavior depends in part on a preference for equitable outcomes. Recent research in behavioral economics assesses variables that influence adult concerns for equity, but few studies to date investigate the emergence of equitable behavior in children using similar economic games. We tested 288 3- to 6-year olds in an anonymous Dictator Game to assess how the value of the currency used affects equity preferences in children. To manipulate value, children played the game with their most or least favorite stickers. At all ages, we found a strong value effect with children donating more of their least favorite stickers than their favorite stickers. We also found a dramatic increase with age in the percentage of children who were prosocial (i.e. donated at least one sticker). However, children who were prosocial tended to give the same proportion of stickers at all ages – about half of their least favorite stickers and 40% of their favorite stickers. These findings highlight the influence of resource value on children's preference for equity, and provide evidence for two different processes underlying altruistic giving: the decision to donate at all and the decision about how much to donate.

WITHDRAWN: Audience effects on moralistic punishment☆ - Corrected Proof

Robert Kurzban, Peter DeScioli, Erin O'Brien — 2006-10-10

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.