Social support, depressed mood, and adjustment to stress: a genetic epidemiologic investigation.

A survey of 821 same-sex female twin pairs from a population-based registry assessed 8 dimensions of social support and social integration. Twin analyses documented significant common environmental influences on 5 of these 8 measures and significant genetic influences on 5 of the 8. A decomposition of the multiplicative association between support and a measure of stressful life experiences in predicting depressed mood--an association typically interpreted as providing evidence for a stress-buffering effect of social support--shows clearly that it is the environmental and genetic factors that cause support, rather than support itself, that buffer the effects of stress on mood in most cases. We discuss the implications of this result for future research on the relationship between social support and psychopathology.     

Rater bias in the EASI temperament scales: a twin study

Under trait theory, ratings may be modeled as a function of the temperament of the child and the bias of the rater. Two linear structural equation models are described, one for mutual self- and partner ratings, and one for multiple ratings of related individuals. Application of the first model to EASI temperament data collected from spouses rating each other shows moderate agreement between raters and little rating bias. Spouse pairs agree moderately when rating their twin children, but there is significantly rater bias, with greater bias for monozygotic than for dizygotic twins. MLE's of heritability are approximately .5 for all temperament scales with no common environmental variance. Results are discussed with reference to trait validity, the person-situation debate, halo effects, and stereotyping. Questionnaire development using ratings on family members permits increased rater agreement and reduced rater bias.     

Learned helplessness and judgments of control

One of the central hypotheses of learned helplessness theory is that exposure to noncontingency produces a reduced ability to perceive response-outcome relations (the postulated "cognitive deficit"). To test this hypothesis, subjects were exposed to a typical helplessness induction task and then asked to make judgments of the amount of control their responses exerted over a designated outcome (the onset of a light). Support for the postulated cognitive deficit would be found if subjects who experienced the induction underestimated the relation between their responses and outcomes. The results, however, demonstrated that induction subjects (n = 30) made higher and more accurate judgments of control than subjects in a no-treatment control group (n = 30). This finding clearly fails to support the postulated cognitive deficit and highlights the need for other direct tests of the basic hypotheses of helplessness theory.     

Daily versus major life events as predictors of symptom frequency: a replication study

Predictions of physical symptomatology by daily life events and by major life events were compared, replicating and expanding work reported by DeLongis, Coyne, Dakof, Folkman, & Lazarus (1982). Analyses of daily, prospective data collected on 79 married men for 90 days demonstrated that daily, undesirable events were better predictors of symptom frequencies than either past, major life events or daily, desirable events. These results, similar to those found by DeLongis et al. (1982), were further explored by examining "healthy" subjects versus subjects with prior medical conditions. Undesirable daily events were a much stronger predictor of physical symptoms in the healthy group than in the prior medical conditions group.     

Altruism and aggression: the heritability of individual differences

Five questionnaires measuring altruistic and aggressive tendencies were completed by 573 adult twin pairs of both sexes from the University of London Institute of Psychiatry Volunteer Twin Register. The questionnaires measured altruism, empathy, nurturance, aggressiveness, and assertiveness. The intraclass correlations for the five scales, respectively, were .53, .54, .49, .40, and .52 for 296 monozygotic pairs, and .25, .20, .14, .04, and .20 for 179 same-sex dizygotic pairs, resulting in broad heritability estimates of 56%, 68%, 70%, 72%, and 64%. Additional analyses, using maximum-likelihood model-fitting, revealed approximately 50% of the variance on each scale to be associated with genetic effects, virtually 0% with the twins' common environment, and the remaining 50% with each twins' specific environment and/or error associated with the test. Correcting for the unreliability in the tests raised the maximum-likelihood heritabilities to approximately 60%. Age and sex differences were also found: altruism increased over the age span from 19 to 60, whereas aggressiveness decreased, and, at each age, women had higher scores than men on altruism and lower scores on aggressiveness.     

Experts, amateurs, and refrigerators: Comparing expert and amateur negotiators in a novel task

Recently a controversy has arisen among behavioral decision theory researchers concerning the generalizability of research based upon student subject samples to the behavior of expert decision makers. This study compared the influence of framing and performance constraints (goals or limits) on the ability of expert and amateur negotiators to reach integrative agreements in a negotiation task novel to both. The results suggested that while experts did outperform amateurs on comparable competitive market simulations, the patterns of their performance as influenced by framing and performance constraints were consistent.     

Effects of decision strategy and number of openings on employment selection decisions

The purpose of this study was to explore the impact of two factors—decision strategy and the number of openings—on selection decisions. Two hundred graduate and undergraduate students participated in a human resource employment screening simulation. Decision strategy was varied by having candidates evaluate resumes and letters of application for 20 candidates one-at-a-time (sequentially) or all at once (simultaneously). The number of position openings was either one or three. Decision strategy affected the number of candidates accepted, acceptance threshold, and decision time. The number of openings affected selection decisions in the simultaneous but not the sequential context. Implications of these results for selection processes are discussed.