Evolutionary Psychology

Kruger, Daniel J.

2008 Evolutionary Psychology

doi: 10.1177/147470490800600407

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.

Stone, Linda

2008 Evolutionary Psychology

doi: 10.1177/147470490800600402

Purzycki, Benjamin Grant; Swartwout, Paul; Sosis, Richard

2008 Evolutionary Psychology

doi: 10.1177/147470490800600409

Jonason, Peter K.; Webster, Gregory D.; Lindsey, A. Elizabeth

2008 Evolutionary Psychology

doi: 10.1177/147470490800600410

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.

Johnson, John A.; Carroll, Joseph; Gottschall, Jonathan; Kruger, Daniel

2008 Evolutionary Psychology

doi: 10.1177/147470490800600414

The current research investigated the psychological differences between protagonists and antagonists in literature and the impact of these differences on readers. It was hypothesized that protagonists would embody cooperative motives and behaviors that are valued by egalitarian hunter-gatherers groups, whereas antagonists would demonstrate status-seeking and dominance behaviors that are stigmatized in such groups. This hypothesis was tested with an online questionnaire listing characters from 201 canonical British novels of the longer nineteenth century. 519 respondents generated 1470 protocols on 435 characters. Respondents identified the characters as protagonists, antagonists, or minor characters, judged the characters' motives according to human life history theory, rated the characters' traits according to the five-factor model of personality, and specified their own emotional responses to the characters on categories adapted from Ekman's seven basic emotions. As expected, antagonists are motivated almost exclusively by the desire for social dominance, their personality traits correspond to this motive, and they elicit strongly negative emotional responses from readers. Protagonists are oriented to cooperative and affiliative behavior and elicit positive emotional responses from readers. Novels therefore apparently enable readers to participate vicariously in an egalitarian social dynamic like that found in hunter-gatherer societies. We infer that agonistic structure in novels simulates social behaviors that fulfill an adaptive social function and perhaps stimulates impulses toward these behaviors in real life.

Howrigan, Daniel P.; MacDonald, Kevin B.

2008 Evolutionary Psychology

doi: 10.1177/147470490800600411

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.

Thoma, Robert J.; Gangestad, Steven W.; Euler, Matthew J.; Lysne, Per A.; Monnig, Mollie; Yeo, Ronald A.

2008 Evolutionary Psychology

doi: 10.1177/147470490800600405

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.

Clark, Andrew P.

2008 Evolutionary Psychology

doi: 10.1177/147470490800600403

Proceptive signals may influence judgments of opposite-sex attractiveness because these signals indicate high mate quality and/or non-threatening behavior but they may also signal high probable rate of return for mating effort. If so, individuals observing these signals may be sensitive to where the signals are directed to; signals directed toward other individuals may not predict what signals would be directed toward the observer. To explore these possibilities I made use of video stimuli composed of mock interviews with actors. Each actor did one proceptive and one unreceptive interview. Each interview was presented as being directed toward participants or toward an opposite sex interviewer. Proceptivity enhanced the attractiveness of opposite-sex actors and an interaction between proceptive state and signal direction was found, with this pattern varying substantially between actors. The possibility that this variation is mediated by the physical attractiveness and sex of the actors will be discussed.

Gustavsson, Linda; Johnsson, Jörgen I.; Uller, Tobias

2008 Evolutionary Psychology

doi: 10.1177/147470490800600404

Evolutionary theory predicts the existence of relatively stable sex differences in partner preferences with, for example, males being more concerned with traits predicting high fertility and females with traits predicting high resource availability. We tested three predictions using personal advertisements from both traditional newspapers and internet dating services. In accordance with predictions, men offered resources more often than did women, and women requested resources more often than did men. Males in all age-categories preferred younger partners. Young females preferred older males, but the pattern was reversed for the majority of females past their fertile period. In contrast to predictions, there was no difference between males and females in the degree to which they offered, or asked for, physical attractiveness. Based on our results and a review of previous studies, we suggest that sex differences in factual or advertised preference for physical attractiveness may be more labile than sex differences in preference for resources and status across societies.

Euler, Matthew; Thoma, Robert J.; Parks, Lauren; Gangestad, Steven W.; Yeo, Ronald A.

2008 Evolutionary Psychology

doi: 10.1177/147470490800600408

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.