USING STIMULUS EQUIVALENCE PROCEDURES TO TEACH NAME-FACE MATCHING TO ADULTS WITH BRAIN INJURIES

On pretests, 3 men with brain injuries matched dictated names of three therapists to written names, but did not match dictated or written names to photos, produce correct names in response to photos, locate offices given written names, or name therapists on sight. Match-to-sample training established conditional relations between dictated names and photos. Posttests showed the emergence of untrained conditional relations involving photos and written names, indicating development of three classes of equivalent stimuli (each containing a dictated name, photo, and written name). For 1 participant, conditional relations involving photos of office nameplates were also examined, but did not emerge pre- or posttraining. Two participants produced names orally when given photos and sorted written names and faces together after training; the 3rd participant was unavailable for these posttests. After training, 1 participant located and named all three therapists in their offices.     

The effect of individual differences in act prototypicality judgments on trait-behaviour correlations and cross-situational consistency

Individuals differ in their perceptions of actprototypicality. This study examined whether incorporating such individual differences enhances trait-behaviour correlations and provides stronger evidence for cross-situational consistency. Three hundred and fifty-three subjects rated the dominance prototypicality of 100 acts, indicated how often they performed each of these acts, and provided trait ratings of how dominant they were in general. There were substantial and reliable individual differences in prototypicality judgements over a 4–5 month period. A variety of weighting schemes were used to incorporate these individual differences, but none dramatically increased the trait-behaviour correlation. Similarly, incorporating individual differences did not increase the magnitude of cross-situational consistency correlations. However, incorporating individual differences did enhance the pattern of trait-behaviour and consistency correlations from less prototypical to highly prototypical acts. Differences in perceptions of act prototypicality thus do not affect the magnitude of the correlations that can be obtained, but they are useful in revealing theoretically meaningful patterns of relationships.     

Continuous attention: rationale and discriminant validation of a test designed for use in psychopharmacology

The continuous attention task (CAT) is a test designed to assess changes in attention due to a variety of factors, for example, drugs. Subjects view a series of 3x3 patterns of squares on a monitor screen, each displayed for 100 msec at intervals of 1.5–2.5 sec, and respond whenever two successive patterns are identical. For such a measure to be validr factors other than attention should be investigated, and shown not to be a factor in performance. Nineteen subjects took part in a study in which information-processing rate and recall of CAT figures was measured. The results showed that a viewing time of 50–60 msec was sufficient for 50% correct recognition of CAT figures, and that recognition with a masked presentation of 100 msec did not differ significantly from an unmaske presentation of 100 msec. Mean recall of CAT figures 2 sec after a 100-msec exposure was 98.2%. These results suggest that performance on the CAT is not limited by either information-processing speed or memory capacity, but is a valid measure of the ability to sustain attention.     

Base-rate effects in category learning: a comparison of parallel network and memory storage-retrieval models

Exemplar-memory and adaptive network models were compared in application to category learning data, with special attention to base rate effects on learning and transfer performance. Subjects classified symptom charts of hypothetical patients into disease categories, with informative feedback on learning trials and with the feedback either given or withheld on test trials that followed each fourth of the learning series. The network model proved notably accurate and uniformly superior to the exemplar model in accounting for the detailed course of learning; both the parallel, interactive aspect of the network model and its particular learning algorithm contribute to this superiority. During learning, subjects' performance reflected both category base rates and feature (symptom) probabilities in a nearly optimal manner, a result predicted by both models, though more accurately by the network model. However, under some test conditions, the data showed substantial base-rate neglect, in agreement with Gluck and Bower (1988b).     

Image Attributions and Smoking Intentions Among Seventh Grade Students

Previous research has indicated that adolescents who intend to smoke differ from those who do not intend to smoke in the imagery they associate with smoking. The present study examined relationships among self-image, ideal self-image, image of smokers in general and image of models in cigarette ads for seventh-grade students. The strongest finding was a positive correspondence of smokers image to self-image in predicting intention to smoke cigarettes. This correspondence between smokers image and self-image derived from a relative depression of self-image in combination with a relative elevation of smokers image for youth who were more likely to report intentions to smoke. There was also a trend for the ideal self-image of youth with greater intentions to smoke to be similarly depressed. It is suggested that when both self-concept and aspirations for self-improvement are diminished, smoking may seem particularly desirable as a means of enhancing identity.     

ASSESSMENT OF STIMULUS PREFERENCE AND REINFORCER VALUE WITH PROFOUNDLY RETARDED INDIVIDUALS

We evaluated a procedure for identifying potential reinforcers with profoundly retarded individuals. In Experiment 1, six persons were repeatedly exposed to 16 stimuli, and approach behaviors to each stimulus were used to identify preferred and nonpreferred stimuli. In Experiment 2, we examined the reinforcing properties of preferred and nonpreferred stimuli by delivering them contingently on the occurrence of arbitrarily selected responses. Results revealed that the preferred stimulus conditions typically produced higher rates of responding than did either the baseline or the nonpreferred stimulus conditions, suggesting that the procedure can be used to assess reinforcer value for individuals with limited behavioral repertoires.