A finding commonly obtained in research using the Buss "aggression machine" is a main effect for trial blocks, indicating an escalation in shock intensity over trials. Theoretical explanations for this effect were tested in a modified verbal operant-conditioning situation. In Experiment 1, subjects could administer any of 10 levels of positive reinforcement to a "learner" for correct verbal responses or any of 10 levels of negative reinforcement to a learner for incorrect responses. Half of the subjects were required to begin with weak, and half with strong, reinforcements. Results indicated that, regardless of condition, subjects gave more intense reinforcements as the learning trials progressed. Those who administered negative reinforcements devalued the learner relative to those who administered positive reinforcements. In Experiment 2, a role-playing procedure was used in which subjects administered either positive or negative reinforcements to a learner whose performance either did or did not improve over trials. Again, in all experimental groups, subjects administered increasingly intense reinforcements over trials. The results are interpreted as supporting a disinhibition theory of anti-and prosocial behavior.Much current experimental work on aggression employs what has been referred to as the "aggression machine" (Buss, 1961) as a means of generating the dependent measure (e.g.,

Pretrial publicity and a temporal interval between the news and trial were explored for their effects upon the jury's deliberation process and verdict. Publicity (neutral, negative) and trial timing (immediate, delayed) were manipulated in a 2 X 2 design. Twenty 12-person simulated juries were exposed either to neutral or negative publicity and viewed a videotaped criminal trial immediately following news exposure or after a one-week delay between news and trial. Dichotomous pre-and postdeliberation verdicts, probability of guilt scales, trial recall, ratings of companion jurors, perceptions of attorneys, assessments of the news article, and recall of news facts were measured. Deliberations were tape recorded and content analyzed. Juries exposed to neutral and negative publicity did not significantly differ on conviction rate, deliberation length, or on quality of deliberations. Prejudicial news elicited counter remarks about the threatening nature of the publicity to the defendant's right to a fair trial. Individual juror data revealed that while the news manipulation did not significantly affect predeliberation verdicts or attention to trial events, negative news lowered jurors' probability estimates of guilt and facilitated their recall of news facts. A discriminant analysis predicting jury verdict indicated a lack of support for prior research showing damaging effects from prejudicial pretrial publicity. Findings are explored for methodological implications and for usefulness of theoretical notions of reactance, and "sleeper effects."Court's faith in the screening mechanism of voir dire and in the ability of 'Requests for reprints should be sent to Roger W. Davis,

Three experiments examined the inhibition of escalation of aggression. Subjects either punished incorrect or rewarded correct responses made by a confederate on a learning task. In Experiment 1, some subjects were interrupted midway through the learning trials, and some of the interrupted subjects coded their responses up to that point. The interruption and coding had no effect on escalation of reinforcement intensity over trials. In Experiment 2, half the subjects were individuated and half were de-individuated. Hall of each group expected to meet the “victim” following the trials and half did not. Neither variable impeded escalation. In Experiment 3, half the subjects were provided with a “hot-line” that could be used to summon the experimenter. Some subjects were also videotaped during the experiment. The presence of the hot-line reduced the overall intensity of aggression relative to the no hot-line group.

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