Psychology, Behavioral

The purpose of this study was to determine whether behavioral contingencies or pharmacological exposure governs the development, loss and retention of tolerance to amphetamine-induced hypophagia in rats. In Experiment 1, rats that had developed tolerance by learning to suppress stereotypy that interfered with feeding from a bottle were divided into three groups to test the retention of tolerance. The Before group received injections of amphetamine (2.0 mg/kg) before access to milk, the After group received injections of amphetamine after access to milk, and the Saline group received injections of saline before access to milk. Both the After and Saline groups lost tolerance when later tested with amphetamine before milk tests. Thus, the loss of tolerance was not a function of drug withdrawal, because drug exposure remained constant in the After group. When milk reward was obtained noncontingently, tolerance was lost even though pharmacological exposure was maintained. Behavioral strategies that were learned while intoxicated were replaced with new learning when the contingencies were changed. Experiment 2 determined that tolerance loss was a function of new learning and not simply ingesting milk in the unintoxicated state. Bottle-fed tolerant rats were given amphetamine prior to intraoral feeding of milk during a retention interval. Subsequent testing with amphetamine in the bottle condition revealed that tolerance was lost. Because the cannula feeding condition does not require suppression of stereotypy, milk reward was available noncontingently in the intoxicated state and tolerance was lost even though drug exposure was maintained. In Experiment 3 rats were given chronic amphetamine injections and intraoral feeding. Subsequent tests with amphetamine and bottle feeding revealed that no tolerance developed. These results demonstrate that even when ingestion occurs in the intoxicated state, no tolerance develops if milk reward is available noncontingently. Animals that drank intraorally were not tolerant when tested in the bottle condition.

Previous research has concluded that individuals high in perspective taking respond less aggressively to provocation than do those low in perspective taking. Whether the perspective-taking effect is automatic or not and many other process-related questions remain largely unanswered. One hundred sixteen female college students participated in a competitive reaction-time task, received escalatory negative feedback purportedly from another participant. In addition to being categorized as either high or low perspective takers, participants also received either high or low levels of situational information about the other and high or low levels of cognitive busyness. Participants high in perspective taking who were under high cognitive load responded significantly less aggressively than did participants low in perspective taking. Results suggest that perspective taking is an automatic process. The findings are discussed in terms of attribution theory, complexity-extremity theory, and in terms of an arousal-dominant response model.

Social representations consist of beliefs, values and norms that influence thought and behavior. Moscovici's Social Representation Theory provides an explanation for how social representations are formed, mutate, and survive, while Dynamic Social Impact Theory provides a framework by which to examine the emergence of macro-social phenomena from everyday communication (i.e., clustering, consolidation and continued diversity). Previous research has not examined, but has assumed, the processes by which social representations of aggression develop. The purpose of the present study was to examine social representations (SRs) of direct and indirect aggression and the process by which SRs emerge from interpersonal communication. Specifically, participants were randomly assigned to fixed addresses in an electronic social space and communicated with four of their nearest neighbors, for four weeks about direct and indirect verbal aggression. In the present study, most people agreed about the aggressiveness of direct responses whereas judgments about indirect responses were relatively varied.

This dissertation involved two studies The first evaluated the hypothesis that the behavior problems which place children at risk for victimization by peers are likely to lead to victimization primarily when children are also at "social risk" for victimization. Social risk was defined as lacking supportive friends or as being rejected by the peer group. Subjects were 229 boys and girls in the third through seventh grades (M age = 11.2 years). Sociometric and peer nomination instruments were used to measure behavior problems, friendship variables, peer rejection, and victimization. As predicted, behavior problems (internalizing problems, externalizing problems, and physical weakness) related more strongly to victimization when children had few friends, had friends who were incapable of fulfilling a protective function (e.g., were physically weak), or were rejected by peers than when children had more friends, had friends capable of defending them, or were better liked by peers. Results support the theory that social risk conditions invite and permit abuse of vulnerable children. Study 2 was a one-year longitudinal investigation designed to evaluate whether the behavioral and social problems that characterize victimized children are antecedents of victimization, consequences of victimization, or both. To examine these issues, 173 children from Study 1 were assessed one year later on the same variables that were measured in Study 1. Results provide information about both the antecedents and the outcomes of victimization.