Work and Rest Variables in the Acquisition of Psychomotor Tracking Skill

College students (75 men, 75 women) matched in preliminary performance of 100 sec on the rotary pursuit apparatus were randomly assigned to five experimental groups. Their work/rest ratios, measured in seconds, were: 20/20, 30/30, 60/60, 90/90,120/120. All subjects received 30 min of total practice time after the matching trial. There was a significant practice effect and a significant practice x conditions interaction, but no main effect due to the cycles’ length or number. The decay rate of reactive inhibition (lr) is probably independent of its prior growth level; hence postrest residual lr is proportional to prerest accumulation. Partly because they generated lr in hypothetically greater amounts, women were significantly less proficient on the average than men, and sex interacted with practice. Although males had higher initial and final levels of ability than females, the two sexes’ acquisition curves showed the same rate parameters in our mathematical model.     

Book Reviews

Book Reviewed
The Politics of Cultural Differences. By David C. Leege, Kenneth D. Wald, Brian S. Krueger, and Paul D. Mueller. Princeton, NJ: Princeton University Press. 2002. 304 pp. $21.95 paper, $60 cloth.
The Psychological Assessment of Political Leaders. Edited by Jerrold M. Post, M.D. Ann Arbor, MI: University of Michigan Press. 2003. 412 pp.
FDR's Body Politics: The Rhetoric of Disability. By Davis W. Houck and Amos Kiewe. College Station, TX: Texas A&M University Press. 2003. 141 + xii pp.
The Power of Legitimacy: Assessing the Role of Norms in Crisis Bargaining. By Christopher Gelpi. Princeton, NJ: Princeton University Press. 2003. 232 pp. $39.50.     

Conjoint design and analysis of the bilinear model: An application to judgments of risk

Conjoint measurement tests which are applicable to a (2 × 2) × (2 × 2) experimental design for the study of the general bilinear model are developed. The tests permit detecting the cause of each failure of the data to satisfy the model, and of measuring the tradeoffs between variables when the model is satisfied. All tests and analyses are illustrated with an application of the model to the assessment of the riskiness of gambles. The method is compared with the use of duplex gambles and other compound and contingent compositions in terms of their appropriate roles in the study of the decision process.     

Variable-ratio schedules of timeout from avoidance: effects of d-amphetamine and morphine.

Rats were trained on concurrent schedules in which pressing one lever postponed shock and pressing the other lever produced periods of signaled timeout from avoidance on variable-ratio schedules. These procedures generated high rates of timeout-reinforced responding and provided a baseline for studying the effects of drugs on behavior maintained by different types of negative reinforcement (shock postponement vs. timeout). Morphine (2.5 to 10.0 mg/kg) reduced behavior maintained by timeout at doses that increased or had no effect on avoidance responding. In contrast, d-amphetamine (0.125 to 2.0 mg/kg) produced large increases in timeout responding at doses that had minimal effect on avoidance in rats trained on variable-interval and variable-ratio schedules. Thus, the event-dependent effects of morphine, observed in previous studies in which timeout responding was maintained at low rates by interval schedules, were replicated with high timeout rates maintained by variable-ratio schedules. The effects of d-amphetamine could also be described as "event dependent" because timeout responding was stimulated more than avoidance regardless of the maintenance schedule or baseline rate.     

How do children form impressions of persons? They average

The experiment reported was concerned with impression formation in children. Twelve subjects in each of Grades K, 2, 4, and 6 rated several sets of single trait words and trait pairs. The response scale consisted of a graded series of seven schematic faces which ranged from a deep frown to a happy smile. A basic question was whether children use an orderly integration rule in forming impressions of trait pairs. The answer was clear. At all grade levels a simple averaging model adequately accounted for pair ratings. A second question concerned how children resolve semantic inconsistencies. Responses to two highly inconsistent trait pairs suggested that subjects responded in the same fashion, essentially averaging the two traits in a pair. Overall, the data strongly supported an averaging model, and indicated that impression formation of children is similar to previous results obtained from adults.     

Attention decrement,temporal variation,and the primacy effect in impression formation

Three experiments which tested the attention decrement explanation of the primacy effect in impression formation are reported. A memory-crowding interpretation of attention decrement would predict a decrease in primacy as the interval between traits is increased. Mild support was obtained in Experiment I but not in II or III. Overall. the magnitude of the primacy effect was independent of intertrait temporal variation. Decrement in attention is the most attractive theoretical explanation for the commonly obtained primacy effect. However, the results of the present series of studies suggest that this explanation is not tenable and that other theoretical mechanisms will be required to account for primacy effects.