The evolution of human intrasexual competition: tactics of mate attraction

Darwin's theory of sexual selection suggests that individuals compete with members of their own sex for reproductively relevant resources held by members of the opposite sex. Four empirical studies were conducted to identify tactics of intrasexual mate competition and to test four evolution-based hypotheses. A preliminary study yielded a taxonomy of tactics. Study 1 used close-friend observers to report performance frequencies of 23 tactics to test the hypotheses. Study 2 replicated Study 1's results by using a different data source and subject population. Study 3 provided an independent test of the hypotheses in assessing the perceived effectiveness of each tactic for male and female actors. Although the basic hypotheses were supported across all three studies, there were several predictive failures and unanticipated findings. Discussion centers on the heuristic as well as predictive role of evolutionary theory, and on implications for other arenas of intrasexual competition.     

Depression and mental control: the resurgence of unwanted negative thoughts

In three experiments we examined depressed individuals' mental control abilities and strategies. Experiment 1 revealed that although depressed college students were initially successful in suppressing negative material, they eventually experienced a resurgence of unwanted negative thoughts. Analysis of subjects' stream-of-consciousness reports indicated that this resurgence was associated with the use of negative thoughts as distracters from the unwanted item. In Experiment 2 depressed subjects acknowledged that positive distracters were more effective than negative ones in suppressing negative thoughts. This acknowledgement suggests that depressed subjects in Experiment 1 did not deliberately focus on negative distracters but that those thoughts automatically occurred because they were highly accessible. Experiment 3 demonstrated that depressed subjects' use of positive distracters could be increased somewhat when we provided such distracters and made them easily accessible. Taken together, the findings suggest that depression involves an enhanced accessibility of interconnected negative thoughts that can undermine mental control efforts.     

Neuroticism, extraversion, and related traits in adult twins reared apart and reared together

The relative importance of genetic and environmental factors for neuroticism, extraversion, impulsivity, and monotony avoidance were estimated in a sample of 99 monozygotic and 229 dizygotic pairs of twins reared apart (TRA) and a matched sample of 160 monozygotic and 212 dizygotic pairs of twins reared together (TRT). The average age was 58.6 (SD = 13.6); 72% of the twins were 50 or older. Model-fitting analyses verified the importance of genetic factors for all four measures; from 23% to 45% of the total variation was attributable to genetic sources. There was considerable evidence that these factors were operating in a nonadditive manner for extraversion and impulsivity. Shared environment accounted for less than 10% of the variance; some evidence for selective placement was found for neuroticism.     

Influence of positive affect on the subjective utility of gains and losses: it is just not worth the risk

A modification of the procedure originally used by Davidson, Suppes, and Siegel (1956) to measure subjective utility was used to study the influence of positive affect on individuals' perceived value (utility) functions. Results indicated, as expected, that persons in whom positive affect had been induced showed a more negative subjective utility for losses than did controls. This indicates that losses seem worse to people who are feeling happy than to those in a control condition. The subjective utility functions of the two groups did not differ as much, however, when people were considering potential gain. Thus, at least in the situation tested in this study, potential gains did not seem to be more appealing (nor less so) for affect subjects than they did for controls. These findings are discussed in relation to theoretical issues in decision making and work suggesting that positive affect can promote increased sensitivity to losses in situations of potential meaningful loss.     

Autonomic arousal feedback and emotional experience: evidence from the spinal cord injured

We interviewed spinal-cord-injured, other handicapped, and nonhandicapped subjects to investigate the relation between the perception of autonomic arousal and experienced emotion. The three groups differed significantly on only one measure of affect intensity, with the spinal-cord-injured subjects more often reporting stronger fear in their lives now compared with the past. In addition, spinal-cord-injured subjects often described intense emotional experiences. Spinal-cord-injured subjects who differed in their level of autonomic feedback differed in intensity on several measures. Subjects with greater autonomic feedback tended to report more intense levels of negative emotions. The findings indicate that the perception of autonomic arousal may not be necessary for emotional experience. There were weak trends in our data, however, suggesting that the perception of arousal may enhance the experience of emotional intensity. The subjective well-being reports of the handicapped groups were comparable to those of nonhandicapped subjects, indicating successful coping with their disability.     

Spontaneous covariations of movement parameters in 5- to 7-year-old boys

The kinematic parameters of to and fro forearm movements in the horizontal plane were investigated in 5- to 7-year-old boys. In one condition, the period of the movements was induced by an acoustic stimulus, while the amplitude was left free. In a second condition, the amplitude of the swing was suggested by a visual frame, but the movement was self-paced. In both conditions, the unconstrained variable (amplitude and period, respectively) was found to covary spontaneously with the constrained variable. The results suggest that, within the age range considered here, motor control processes do not conceive of amplitude and velocity as two independent variables.