The perception of preschool social dominance

Children's and teachers' perception of social dominance was examined using a behavioral criterion for determining accuracy of verbal judgments. Video records of agonistic interactions were obtained during approximately 60 hours of free-play at two preschool centers. Analyses of social conflict episodes ending in submission revealed linear dominance structures for both groups. Dominance perception was assessed in two ways. Both teachers and children were asked to rank-order a subgroup of children according to dominance. They were also asked to select the more dominant children in a number of predetermined pairs. Results indicated that teachers could accurately judge dyadic dominance relations, and that accuracy among children varied as a function of their status within the group hierarchy. Findings have implications for social dominance assessment methodology, and for the issue of consensual versus ecological validity in developmental studies of social perception.     

Factors in the waning of muricide in the rat: I. Analysis of intra- and intersession decrement

If each mouse killed by a rat is removed from the rat's home cage and replaced immediately by another live mouse, the rate of killing declines within 1- and 3-hr sessions. Muricide could not then be dishabituated by either a “nonspecific” stimulus (a loud noise) or a specific change in target characteristics (a frog substituted for the mouse). By systematically varying intersession intervals, we found that 1 hr of ad lib killing produced a monotonically decreasing suppression of muricide over the succeeding 96 hr. Subjects performed an interesting kind of forward didng which was influenced by both dishabituating stimuli and killing; this may be a form of die placement behavior.     

Effects of D- and L-amphetamine on the predatory behavior of Southern grasshopper mice,onychomys torridus

Adult male and female southern grasshopper mice (Onychomys torridus) were tested for predatory aggression toward cricket prey 1 hr after single injections of d-amphetamine (1 or 10 mg/kg) or 1-amphetamine (1 or 10 mg/kg). At the lower dose, d-amphetamine decreased feeding behaviors, while I-amphetamine altered attack-related behaviors. At the higher dose, both stereoisomers appeared to be equipotent in significantly decreasing 5 measures of predatory aggression. These results suggest that brain dopamine and norepinephrine play important roles in the regulation of predatory aggression of Onychomys torridus.