The multifaceted nature of unsupervised category learning

A substantial portion of category-learning research has focused on one learning mode--namely, classification learning (a supervised learning mode). Subsequently, theories of category learning have focused on how the abstract structure of categories (i.e., the co-occurrence patterns of feature values) affects acquisition. Recent work in supervised learning has shown that a learner's interactions with the stimulus set also plays an important role in acquisition. The present study extends this work to unsupervised learning situations involving simple one-dimensional stimuli. The results suggest that categorization performance is a function of both learning mode (i.e., study conditions) and learning problem (i.e., category structure). Unsupervised learning, like supervised learning, appears to be multifaceted, with different learning modes best paired with certain learning problems.     

MOTHERS AS EFFECTIVE THERAPISTS FOR AUTISTIC CHILDREN'S PHOBIAS

Two autistic children were treated for specific fears. A three-component participant modeling procedure was implemented within a multiple baseline design across subjects. Children were exposed gradually to fearful situations, with mothers serving as therapists and reinforcers. Dependent measures were (a) number of approach steps completed, (b) frequency of verbalizations and vocalizations of fear, and (c) overall appearance of fear. Following treatment, the children functioned effectively in previously fearful situations without verbalizations or appearance of fear. Five-month and 1-year follow-up assessments with 1 child showed maintenance of treatment effects.     

Humor appreciation as a function of sexual,aggressive, and sexist content

The purpose of the present investigation was to examine the relationship between the rated sex, aggression, and sexism values of cartoons with their rated funniness values. Multiple regression analyses indicated that for women, only sexism values correlated with cartoon funniness, albeit negatively. For men, however, only sex values correlated (positively) with cartoon funniness. The results were interpreted by Zillmann's social predisposition theory. Women, more likely having been victims of sex discrimination, identified with the cartoon victim and thus found sexist cartoons less funny. Men, because of their social history, made no such identification and were more aware of the sexual aspects of the cartoons. This influenced their funniness ratings of the cartoons, which replicated previous research.     

Hurricane Andrew: Psychological distress among shelter victims

This study examined psychological distress and functioning among Hurricane Andrew victims who lost their homes and were living in shelters. Four and one-half weeks after Hurricane Andrew struck southern Florida, 89 (45 males, 44 females) Blacks, Hispanics, and Whites completed a questionnaire. The questionnaire asked for information about psychological and psychophysiological symptoms, use of mental health services, coping responses, and extent of preparation for the storm. The findings suggest that loss of home and property were related to distress and depression. About one-quarter of the sample were moderately depressed. Over one-third of the sample reported experiencing psychological and psychophysiological distress. Approximately one-half of the subjects did not take the hurricane warnings seriously. White subjects began preparing earlier for the storm, and evacuated their homes more frequently than did Black subjects. Implications of the findings and future research directions are discussed.     

Rehearsal in Spatial Working Memory: Evidence From Neuroimaging

A variety of biological evidence has identified a frontal-parietal circuit underlying spatial working memory for visual stimuli. But the question remains, how do these neural regions accomplish the goal of maintaining location information on-line? We tested the hypothesis that the active rehearsal of spatial information in working memory is accomplished by means of focal shifts of spatial selective attention to memorized locations. Spatial selective attention has been shown to cause changes in the early visual processing of stimuli that appear in attended locations. Thus, the hypothesis of attention-based rehearsal predicts similar modulations of visual processing at memorized locations. We used functional magnetic resonance imaging to observe posterior visual activations during the performance of a spatial working memory task. In line with the hypothesis, spatial rehearsal led to enhanced activation in the early visual areas contralateral to the memorized locations.     

At-Risk Urban High School Students' Commitment to Career Choices

The purpose of this study was to examine the commitment to career choices process for at-risk urban high school students. Data from 189 at-risk urban high school students were sampled. Results indicated that students' level of commitment to their career choices was related to their vocational identity, their need for occupational information, their perceived barriers to occupational goals, and the number of occupations they considered. The tendency to foreclose was related to the adherence to career myths. Implications and limitations for career theory, research, and practice are addressed.     

Distractor selection ratios

A latent variable representation for multiple-choice item and option characteristic curves is presented. Under standard assumptions of conditional independence of item responses and monotonicity of item characteristic curves, a criterion for distractors is proposed based on distractor selection ratios. A connection is made between the proposed criterion and the theory of individual choice behavior, providing new insight. The main results allow for the testing of the criterion from observable data without first specifying a parametric form for the characteristic curves. A series of examples apply the method.     

The effect of temporal and force changes on the patterning of sequential movements

Summary This article examines the programming of relatively long sequences of action with the control of sequential movements being effected through the use of a tapping task involving a sequence of five taps. Subjects were required to tap with their right hand at rates of 150, 200, and 250 ms. There were two conditions, with subjects being required either to increase, in condition 1, or to decrease, in condition 2, the force at one of the five tap positions (all five tap positions were examined), then return to the previous force level. Changes in timing resulting from variations in the force characteristics have previously been discussed in terms of changes in the organizational time required ( Semjen, Garcia-Colera, & Requin, 1984). The current study breaks the intertap interval down into two separate components: the contact interval (finger in contact with the key) and the non-contact interval (interval preceding the tap). Although changes in the non-contact interval could be explained in terms of changes in the organizational time required, changes in the contact interval appeared to be a result of the mechanical changes in force.     

The Construct Validity of Assessment Centre Performance Dimensions

Evidence regarding the construct validity of assessment centre performance dimensions is reviewed. The evidence strongly suggests that variance in ratings tends to reflect exercises more than individual performance dimensions, thus calling into question the construct validity and utility of these dimensions. A number of biases in the assessment centre process, as well as more general rating biases are noted that may be responsible for these pervasive exercise effects. Suggestions are made for enhancing the construct validity of performance dimensions.