Accuracy in the judgment of in-group and out-group variability

The accuracy of in-group and out-group variability judgments was examined by comparing those judgments with the variability of self-ratings provided by random samples of group members. Following Park and Judd (1990), perceptions of both group dispersion and group stereotypicality were examined. Accuracy was examined both by within-subject sensitivity correlations and by simple discrepancies between perceived and actual variability estimates. In-group-out-group differences in sensitivity were shown, particularly for judgments of stereotypicality. These differences were related to differences in the degree to which out-group variability is underestimated relative to in-group variability (i.e., the out-group homogeneity effect). Out-group stereotypicality judgments were overestimated, supporting the view that out-group stereotypes are overgeneralizations. Whether dispersion judgments were over- or underestimated depended on their measurement.     

Three methods of developing MMPI taxonomies of sexual offenders

In a sample of 261 state hospital sexual offenders, Minnesota Multiphasic Personality Inventory (MMPI) profiles did not differ for offenders with adult victims versus offenders with child victims when offender age was controlled. MMPI 2-point analyses for the whole sample revealed five common codes that were independent of victim maturity. The sample was randomly divided in half and subjected to a cluster-analytic procedure which revealed two MMPI clusters. The first cluster was unelevated, with Scale 4 as its high point. The second cluster had multiple elevations, with Scales 8, 4, 2, and 7 as the highest scales. These clusters were replicated in a cluster analysis of the second half of the sample. However, when the sample was recombined, the two clusters were not externally validated basis on demographic and criminological variables. The results suggest that common psychological variables among sexual offenders may have more discriminative value than victim maturity in developing sexual offender taxonomies.     

Choice as a function of local versus molar reinforcement contingencies.

Rats were trained on a discrete-trial probability learning task. In Experiment 1, the molar reinforcement probabilities for the two response alternatives were equal, and the local contingencies of reinforcement differentially reinforced a win-stay, lose-shift response pattern. The win-stay portion was learned substantially more easily and appeared from the outset of training, suggesting that its occurrence did not depend upon discrimination of the local contingencies but rather only upon simple strengthening effects of individual reinforcements. Control by both types of local contingencies decreased with increases in the intertrial interval, although some control remained with intertrial intervals as long as 30 s. In Experiment 2, the local contingencies always favored win-shift and lose-shift response patterns but were asymmetrical for the two responses, causing the molar reinforcement rates for the two responses to differ. Some learning of the alternation pattern occurred with short intertrial intervals, although win-stay behavior occurred for some subjects. The local reinforcement contingencies were discriminated poorly with longer intertrial intervals. In the absence of control by the local contingencies, choice proportion was determined by the molar contingencies, as indicated by high exponent values for the generalized matching law with long intertrial intervals, and lower values with short intertrial intervals. The results show that when molar contingencies of reinforcement and local contingencies are in opposition, both may have independent roles. Control by molar contingencies cannot generally be explained by local contingencies.     

Stimulus control of Pavlovian facilitation

Two experiments were conducted using an autoshaping procedure with pigeons to examine whether dimensional stimulus control by a Pavlovian facilitator parallels the control established following operant discrimination training. Facilitation training consisted of the presentation of a black vertical line on a white background as the B stimulus in a feature-positive discrimination in which the A stimulus (white keylight) was followed by grain presentation only if preceded by B. In this way, B facilitates or sets the occasion for pecking at A. Subsequent testing for generalization along the line-orientation dimension produced decremental gradients when the facilitation paradigm incorporated an explicit feature-negative stimulus (B−). These results parallel the decremental control obtained following operant discrimination training and suggest that Pavlovian facilitators and instrumental discriminative stimuli are functionally equivalent.     

Accuracy of weightbearing at three target levels during bilateral upright stance in patients with neuropathic feet and control subjects

The purposes of this study were to (1) describe errors in weightbearing at three target levels for patients with neuropathic feet and control subjects, (2) compare the absolute errors at the three target levels between groups, and (3) identify predictor variables of errors in weightbearing by the neuropathic group. The groups of 26 subjects were matched for age and height. Weightbearing was measured with digital scales while subjects attempted to adjust their weight through a designated lower extremity to each target level (25, 50, and 75% of body weight). Analysis of variance indicated no significant difference in the percentage weightbearing between groups at the three target levels. There was a significant difference in errors made in weightbearing by the groups at the three target levels. Mean errors ranged from 8.5 to 9.7% for the neuropathic group and from 2.4 to 6.6% for the control group. The findings cast doubt on the utility (in the absence of feedback) of requesting individuals, particularly those with neuropathic feet, to weightbear at specific target levels.     

Comparison of two locus of control scales in predicting relapse in an alcoholic population

A 3-mo. follow-up was made of 64 male veterans who were discharged from a 21-day Alcohol Detoxification Treatment Program at the Veterans Affairs Medical Center at Lyons, NJ. Scores on the Rotter I-E and Alcohol Responsibility Scales were significantly correlated with tendencies toward a more external direction among the 13% who relapsed, significant on the I-E scale and nonsignificant on the Alcohol Responsibility Scale. When tests were compared as possible predictor variables of alcoholic relapse, the difference in favor of the I-E scale was statistically nonsignificant.