Countries with fewer males have more violent crime: marriage markets and mating aggression

Violent crimes (murders, rapes, and assaults) are substantially higher in countries with a relative scarcity of men according to research using INTERPOL data [Barber, 2000a]. This is a paradox given that males are more criminally violent and likely reflects increased direct mating competition. The present research sought to confirm and extend Barber's [2000a] finding, using murder data from the United Nations and homicides from World Health Organization that are of higher quality than the INTERPOL data, and using more rigorous controls. In addition to level of economic development, control variables included, income inequality, urbanization, population density, the number of police, and whether the country was a major center of illegal drug trafficking. Regression analyses with all controls found that killings in both data sets increased with declines in the male proportion of the population. The findings are discussed in terms of direct reproductive competition and alternative explanations are considered.     

From steroids to nation states: An integrated evolutionary approach to violent crime

Most evolutionary psychologists emphasize the individual level of analysis concerning violent crime and other dependent variables. This paper outlines a strategy for evolutionary explanation of societal variation across time as well as space and applies it to crimes of violence. The central idea is that individual adaptations for reproductive competition play out differently depending both on developmental context and societal conditions, including the marriage market. Violent crimes (murders, rapes, and assaults) are substantially higher in countries with a relative scarcity of men according to research using INTERPOL and World Health Organization data [Barber, N. (2000a). The sex ratio as a predictor of cross-national variation in violent crime. Cross-Cultural Research, 34, 264–282, Barber, N. (2009). Countries with fewer males have more violent crime: Marriage markets and mating aggression. Aggressive Behavior, 35, 49–56]. This is an apparent contradiction given that males are more criminally violent and likely reflects increased direct mating competition that evokes increased testosterone production for humans as for other species. The empirical evidence is discussed in terms of direct reproductive competition and various alternative explanations, particularly the “culture of violence” and socialization experiences are considered.     

The Influence of Abnormal Sex Differences in Life Expectancy on National Happiness

Countries with better health, as indexed by life expectancy, score higher on subjective well-being (SWB). It was predicted that deviations from the average sex difference in life expectancy (reflecting reproductive competition among males and discrimination against females) would be inversely related to happiness. Regression analysis of SWB for 178 countries found that deviations from the average sex difference in life expectancy were predictive of unhappiness controlling for life expectancy, national wealth, and income inequality. Countries with a relative scarcity of female children (used as an index of parental bias) were less happy. Societies in which there is an undue burden on the health and survival of either sex are thus unhappy ones due to gender-specific disadvantage and associated gender conflict.     

Beliefs and data on the relationship between consistency and accuracy of eyewitness testimony

Two studies concerned with consistency and accuracy of eyewitness testimony were conducted. In Study 1 potential jurors indicated the degree to which they considered that various witness on‐stand behaviours indicated testimonial accuracy. Witness statements that were inconsistent with previous statements were considered to be the strongest indicators of inaccuracy. Study 2 examined the relationship between consistency and accuracy of testimony. Witnesses viewed a film of a robbery and were interviewed twice (2 weeks apart) about the crime in a 4 (interview format)×2 (interview occasion) design. Regardless of whether consistency was operationalised in terms of direct contradictions between interviews, or degree of agreement on detail across interviews, no more than 10% of the variance in overall accuracy rate was explained by any individual measure. Number of contradictions and overall agreement between interviews did, however, make additive contributions to prediction of overall accuracy. Also, higher correlations between contradiction‐based consistency measures and interview two accuracy rate were detected. Neither consistency nor accuracy for specific testimonial dimensions were predictive of accuracy on the other dimensions, or overall accuracy. Copyright © 1999 John Wiley & Sons, Ltd.     

Characterizing the Linguistic Chameleon: Personal and Social Correlates of Linguistic Style Accommodation

Linguistic style accommodation between conversationalists is associated with positive social outcomes. We examine social power and personality as factors driving the occurrence of linguistic style accommodation, and the social outcomes of accommodation. Social power was manipulated to create 144 face‐to‐face dyadic interactions between individuals of high versus low power and 64 neutral power interactions. Particular configurations of personality traits (high self‐monitoring, Machiavellianism and leadership, and low self‐consciousness, impression management and agreeableness), combined with a low‐power role, led to an increased likelihood of linguistic style accommodation. Further, greater accommodation by low‐power individuals positively influenced perceptions of subjective rapport and attractiveness. We propose individual differences interact with social context to influence the conditions under which nonconscious communication accommodation occurs.     

Differential dependence of Pavlovian incentive motivation and instrumental incentive learning processes on dopamine signaling

Here we attempted to clarify the role of dopamine signaling in reward seeking. In Experiment 1, we assessed the effects of the dopamine D(1)/D(2) receptor antagonist flupenthixol (0.5 mg/kg i.p.) on Pavlovian incentive motivation and found that flupenthixol blocked the ability of a conditioned stimulus to enhance both goal approach and instrumental performance (Pavlovian-to-instrumental transfer). In Experiment 2 we assessed the effects of flupenthixol on reward palatability during post-training noncontingent re-exposure to the sucrose reward in either a control 3-h or novel 23-h food-deprived state. Flupenthixol, although effective in blocking the Pavlovian goal approach, was without effect on palatability or the increase in reward palatability induced by the upshift in motivational state. This noncontingent re-exposure provided an opportunity for instrumental incentive learning, the process by which rats encode the value of a reward for use in updating reward-seeking actions. Flupenthixol administered prior to the instrumental incentive learning opportunity did not affect the increase in subsequent off-drug reward-seeking actions induced by that experience. These data suggest that although dopamine signaling is necessary for Pavlovian incentive motivation, it is not necessary for changes in reward experience, or for the instrumental incentive learning process that translates this experience into the incentive value used to drive reward-seeking actions, and provide further evidence that Pavlovian and instrumental incentive learning processes are dissociable.     

The recovery of a visually masked target

Ss were briefly shown pairs of letters under backward masking and disinhibitive backward masking conditions. For the backward masking condition, a single homogeneous flash of light (M1), varying in duration, followed the presentation of letters after a varying delay (IS11), and recognition of the target letters (TS) was found to be a function of M1 duration and ISI1. For the disinhibition condition, a variable second mask (M2) followed M1 after a variable delay (ISI2) and disinhibition of M1’s effect on TS recognition occurred. Provided the ISIs were adequate, a relatively powerful M2 wass found to disinhibit a moderate Ml’s effect on the TS. Current theories of visual masking were examined in the light of these findings.