Elevation and reduction of plasma tryptophan and their effects on aggression and perceptual sensitivity in normal males

Data from experimental animals suggest that 5-hydroxytryptamine (5HT) may have an inhibitory effect on aggression, while clinical studies have found a correlation between pathological aggression and low brain 5HT. To investigate this relationship further we used amino acid mixtures designed to raise or lower the levels of the 5HT precursor, tryptophan. Normal male subjects were given tryptophan-depleted, balanced, or tryptophan-supplemented ammo acid mixtures and tested for aggression 5 hours later. The balanced amino acid mixture served as a control for the tryptophan depletion and supplementation. Testing for aggression was done using the Buss paradigm in which subjects deliver electric shocks to a (nonexistent) partner in response to stimulus tones. Duration and intensity of shock delivered were the measures of aggression, while responsivity to the stimulus tones was the measure of perceptual sensitivity. Neither tryptophan supplementation nor tryptophan depletion had any effect on these measures of aggression or perceptual sensitivity. We conclude that raising or lowering the synthesis of brain 5HT through alterations in tryptophan availability does not influence aggression in normal males as measured by the Buss task.     

Fighting in female mice in lines selected for laterality

Male and female mice from the Collins HI and LO laterality strains were isolated for 3–5 days. Thereafter on Day 1 each was given the Intruder Test followed by a Training Test; the latter was repeated 1 week later. All males of 36 days or older fought vigorously, but without line differences. Females of the HI strain showed higher numbers of fighters and greater intensity of fighting than those of the LO strain, and by the second Training Test these differences were significant at p < 0.01. The HI and LO laterality strains thus provide useful tools for investigating the functions of female agonistic behavior and the possible relationship between laterality and the expression of aggression.     

Pregrouping aggression and defense scores influences alcohol consumption for dominant and subordinate rats in visible burrow systems

Five male/two female rat colonies were established in visible burrow systems, with males selected for pregrouping attack scores and also evaluated in open field and cat odor tests. Dominant-subordinate pregrouping attack differences suggested that the males becoming dominant are those showing more persistent and higher level attack. For six colonies showing dominant-subordinate behavioral differences, pregrouping defense tests failed to predict subordinate status. However, pregrouping defense scores were reliably correlated with subordinate pre-postgrouping change scores for voluntary ethanol consumption. Subordinates showed higher ranked ethanol consumption than dominants, but these groups were not different on pregrouping ethanol consumption. Subordinate postgrouping ethanol consumption was positively correlated with pregrouping attack toward an adult intruder, consonant with previous findings that highly aggressive subordinates are the targets of more intense attack by dominants. These results provide further support for a view that subordination stress increases voluntary ethanol consumption in male rats and suggest some additional individual differences factors that may be involved in increased ethanol consumption for male subordinates. © 1992 Wiley-Liss, Inc.     

When is the Wilcoxon–Mann–Whitney procedure a test of location? Implications for effect-size measures

The Wilcoxon–Mann–Whitney procedure is invariant under monotone transformations but its use as a test of location or shift is said not to be so. It tests location only under the shift model, the assumption of parallel cumulative distribution functions (cdfs). We show that infinitely many monotone transformations of the measured variable produce parallel cdfs, so long as the original cdfs intersect nowhere or everywhere. Thus there are infinitely many effect sizes measured as shifts of medians, invalidating the notion that there is one true shift parameter and thereby rendering any single estimate dubious. Measuring effect size using the probability of superiority alleviates this difficulty.     

The Participation and Motivations of Grant Peer Reviewers: A Comprehensive Survey

Science and Engineering Ethics - Scientific peer reviewers play an integral role in the grant selection process, yet very little has been reported on the levels of participation or the motivations...     

Framing and Group Decision-Making: Do Cognitive Changes Parallel Preference Changes?

Subjects had their initial frames of reference concerning a decision problem (Asian Disease problem; Tversky & Kahneman, 1981, Science,211, 453–458) manipulated in order to compose four-person groups containing members with different frames of reference. Three different group compositions (number of members with "gain-oriented" vs "loss-oriented" frames) were used: three gain-oriented and one loss oriented (3–1), two gain-oriented and two loss-oriented (2–2), and one gain-oriented and three loss-oriented (1–3). Results indicated a postgroup discussion choice shift toward the risk alternative in the 2–2 and the 1–3 composition conditions. However, changes in members′ frames of reference were unrelated to preference changes. Group composition also affected group decision processes. Implications for future theory and research in small group decision-making are discussed.     

Mediating factors in chick social pecking: II. effects of exposure to movement

Unfamiliarity with movement may lead isolated chicks to respond aggressively when tested with live, moving conspecifics. This hypothesis was tested by comparing the number and locus of pecks by isolated chicks to a stationary or moving model of a chick, and to a live chick. In a second test of the hypothesis chicks that viewed a moving object during isolation and chicks isolated without movement were tested with a live con-specific and their number and locus of pecks were compared. Neither experiment supported the hypothesis. Movement alone failed to excite aggressive pecks and prior experience with movement failed to suppress aggressive pecks. In the first experiment imlated chicks treated the live testmate more aggressively than the moving or stationary model. In the second experiment aggressive pecking of chicks was unaffected by prior experience with movement, These fmdmgs do not support the hypothesis that movement excites aggression in isolated chicks. Nonetheless the results focus attention on the generally neglected problem of emotional and motivational states produced by isolation.     

The convergent and discriminant validity of subjective fit perceptions

This study examined whether employees develop perceptions about 3 different types of fit: person-organization fit, needs-supplies fit, and demands-abilities fit. Confirmatory factor analyses of data from 2 different samples strongly suggested that employees differentiate between these 3 types of fit. Furthermore, results from a longitudinal design of 187 managers supported both the convergent and discriminant validity of the different types of fit perceptions. Specifically, person-organization fit perceptions were related to organization-focused outcomes (e.g., organizational identification, citizenship behaviors, turnover decisions), whereas needs-supplies fit perceptions were related to job- and career-focused outcomes (e.g., job satisfaction, career satisfaction, occupational commitment). Although demands-abilities fit perceptions emerged as a distinct construct, they were not related to hypothesized outcomes (e.g., job performance, raises).