The children of Mexican-American migrant workers: A population at risk?

The present study assessed intellectual, academic, and emotional strengths and weaknesses for a group of Mexican-American children of migrant farm workers. In order to test the vulnerability hypothesis, the test profiles of these children were contrasted with those of two groups of black children with similar demographic makeup. The children of one group (Clinical Black) had been referred previously for a psychological consultation while the children of the other (Nonreferred Black) had not. Across dependent measures, between-groups contrasts tended to describe the scores of the Migrant children as similar to those of the Clinical Black children and significantly below those of the Nonreferred Black children. The findings suggested specific intellectual, academic, and emotional vulnerabilities of the Migrant children and demonstrated the need to develop ameliorative programs for these children.The authors wish to thank the staff of C & Y, University of Virginia Hospital, especially Ms. Deborah Johnson and Ms. Suzanne Canale, whose cooperation and assistance made this project possible.     

A test of the self-perception explanation of the effects of rewards on intrinsic interest

An experiment was conducted to test the proposition that rewards undermine or enhance intrinsic interest in a task to the extent that individuals interpret their behavior as being motivated by the reward. It was predicted that when subjects were denied the opportunity to develop and confirm this attribution, rewards would not produce an undermining effect, but rather would enhance dispositions and behavior. Subjects were recruited to evaluate a new sugar-free soft drink. Two levels of incentives (reward-no reward), two levels of examination (opportunity-no opportunity), and three levels of outcome (good-neutral-poor) were employed. The results support the prediction that an incentive's effect depends on the examination opportunity. In the examination condition, rewarded subjects attributed their behavior more to external factors than did unrewarded subjects, but gave more negative product evaluations only after tasting it. In the no examination condition, there were no differences in the attributions made by rewarded and unrewarded subjects, and rewarded subjects were more positively disposed toward the product both before and after tasting it. These results are explained as a consequence of two properties of rewards, enhancement through reinforcement and undermining through discounting, and of hypothesis-testing processes.     

Interaction of genetics and separation in canine hyperkinesis and in differential responses to amphetamine

A model of childhood hyperkinesis, using the Telomian-beagle hybrid dog, is described, demonstrating the interactions of genetics and separation in the development of this syndrome and in the favorable responses of some of these dogs to amphetamine. This work represents the collaboration of three laboratories, utilizing chiefly methods of inhibitory training. Inducing separation distress enhanced the resistance to inhibitory training and the favorable responses to amphetamine.     

Loudness and loudness discrimination

A model is developed which holds that pure-tone intensity discrimination and suprathreshold loudness judgments are based on the same sensory representation. In this model, loudness is a power function of sound intensity. When two tones are presented sequentially, each gives rise to a loudness value along the sensory continuum. In intensity-discrimination experiments, threshold is reached when the loudness difference between the tones exceeds a criterial value. For suprathreshold presentations of tone pairs, judgments of loudness differences are based on the loudness difference between the two tones. The model is shown to accord well with data from both classes of experiments.     

The role of proprioception in the perception and control of human movement: Toward a theoretical reassessment

The theoretical role of proprioception in the perception and control of human movement is elusive because of the obvious inability to manipulate experimentally the various receptive systems. Individuals who have had the metacarpophalangeal joint and joint capsule removed and replaced with silastic inserts afford a unique opportunity to evaluate a principal source of proprioception, namely, slowly adapting joint afferents. In a set of experiments, we show that such individuals show no deficits in finger localization following joint replacement. We take this and other complementary findings as a preliminary basis for proposing a dynamic rather than kinematic account of movement production. In addition, we provide a reconceptualization of the function of proprioceptive information in the CNS. Our arguments focus on proprioceptive inputs as tuning or modulating interneuronal pools rather than providing dimension-pecific information to the brain, as is commonly assumed.     

An investigation of the arousal model of interpersonal intimacy

In a study designed to test Patterson's arousal model of nonverbal intimacy, the heartrate, gaze, smiles, body orientation, and body lean of each of 40 female subjects who interacted with an accomplice were measured. Within a factorial design, subjects were induced to view more or less favorably the accomplice, who subsequently increased or maintained the same level of nonverbal immediacy as she did in an earlier session. It was hypothesized that (1) an increase in the accomplice's immediacy would effect an increase in subjects' arousal (heartrate) which, in turn, (2) would lead to either reciprocal or compensatory nonverbal adjustments by subjects, depending on whether they viewed the accomplice more or less favorably, respectively. The results supported the first but not the second hypothesis. However, interpretation of the results suggests, nevertheless, that they may be consistent with the arousal model.     

Effects of sentential stress and word class upon comprehension in Broca's aphasics

The roles which word class (open/closed) and sentential stress play in the sentence comprehension processes of both agrammatic (Broca's) aphasics and normal listeners were examined with a word monitoring task. Overall, normal listeners responded more quickly to stressed than to unstressed items, but showed no effect of word class. Aphasics also responded more quickly to stressed than to unstressed materials, but, unlike the normals, responded faster to open than to closed class words regardless of their stress. The results are interpreted as support for the theory that Broca's aphasics lack the functional underlying open/closed class word distinction used in word recognition by normal listeners.