The effects of practice on object-based, location-based, and static-display inhibition of return

We report two experiments that examine the effects of practice on object-based, location-based, and static-display inhibition of return (IOR). The results are clean All three effects get smaller with practice. These findings are at odds with the results of Müller and von Mühlenen (1996), who failed to observe object-based IOR and detected no effect of practice on static-display IOR. However, their subjects were more practiced than ours prior to data collection. We suggest, therefore, that the reducing effect of practice on IOR might have occurred in their unrecorded practice sessions. We also discuss a two-process model in which IOR is seen as the net effect of underlying inhibitory and excitatory processes. In such models (e.g., Solomon & Corbit,1974), practice often results in a reduction of the net effect of the two processes.     

An investigation of hierarchical Bayes procedures in item response theory

Hierarchical Bayes procedures for the two-parameter logistic item response model were compared for estimating item and ability parameters. Simulated data sets were analyzed via two joint and two marginal Bayesian estimation procedures. The marginal Bayesian estimation procedures yielded consistently smaller root mean square differences than the joint Bayesian estimation procedures for item and ability estimates. As the sample size and test length increased, the four Bayes procedures yielded essentially the same result.The authors wish to thank the Editor and anonymous reviewers for their insightful comments and suggestions.     

Being human,more or less

Robert G. Woodhouse Memorial Philosophy Lecture, Rockland Community College of the State University of New York, Tuesday, 1 December 1992.     

Casuistry in medical ethics: Rehabilitated,or repeat offender?

For a number of reasons, casuistry has come into vogue in medical ethics. Despite the frequency with which it is avowed, the application of casuistry to issues in medical ethics has been given virtually no systematic defense in the ethics literature. That may be for good reason, since a close examination reveals that casuistry delivers much less than its advocates suppose, and that it shares some of the same weaknesses as the principle-based methods it would hope to supplant.     

Effects of chronic ethanol consumption on gestation and lactation in rats

Chronic consumption of ethanol during pregnancy and lactation may lead to abnormalities in the fetus or infant. A group of female Wistar rats was submitted to ethanol treatment over a period of a month. A pair-fed control group received sucrose solution isocaloric to ethanol and the control group received water “ad libitum.” Afterward, the females were mated with males over a period of 20 days. At birth, each litter was maximized to eight pups and the remaining ones were decapitated to remove the fetal blood and brains. No significant difference was observed in fetal body and brain weight at birth. During lactation the ethanol and pair-fed groups gained less weight than the control group. After weaning, their weight became similar. Fetal blood glucose levels were decreased in the ethanol-treated group. One hundred percent of the pair-fed and control females delivered live fetuses at term and all survived; only 40% of the females in the ethanol group delivered, and one pup did not survive. Chronic ethanol treatment pointed to a possible reduction in the fertility. It seems likely that the change in body weight of ethanol-fed dams was caused by undernutrition.     

The effects of token reinforcement,feedback and response cost on standardized test performance

The primary purpose of the present study was to compare the differential effects of token reinforcement, feedback, and response cost on the test performance of delinquent boys. Eighty students were randomly assigned to three experimental groups and one control group of 20 subjects each. Each experimental group received a standard and a modified administration of the verbal section of the WISC. For the token reinforcement group, the modified WISC administration permitted students to earn tokens contingent on correct responses; the response cost group forfeited tokens contingent on incorrect responses; and the feedback group simply received information regarding the accuracy of each response. The control group received two standard WISC administrations. The primary measure was the difference in verbal I.Q. scores between the standard and modified WISC administrations. Results indicated that the token reinforcement and response cost groups achieved significantly higher scores than the feedback and control groups. No significant differences were found between the token reinforcement and response cost groups nor between the feedback and control groups. The implications of these findings for clarifying the relationship between motivational condition and test performance are discussed.     

A Preventive Approach to School Violence and Vandalism: An Experimental Study

School violence and vandalism are at crisis level. The investigators attempted to employ strategies that would attack identified procreators of school violence and vandalism existing within our schools. The effects of these strategies on vandalism costs, student attendance, off-task and disruptive behaviors, and on various kinds of positive teacher-student contacts were investigated in 19 elementary schools. Results indicated that the dollar costs of vandalism and frequency of inappropriate student behaviors decreased more in experimental than in control schools. Student attending and positive teacher-student contacts improved, or remained higher, in the experimental than in the control schools.