Incidental learning,attention, and curiosity in squirrel monkeys calorie deprived as infants

The long-term effects of infantile malnutrition on information processing were studied in squirrel monkeys. From 2 through 8 weeks of age, four low-calorie infants were fed reduced amounts of a high protein diet, limiting their mean body weight gain to 23% of that of four well-fed controls, with all of this gain occurring during the first 2 weeks on the low-calorie diet. Thereafter, both groups received the standard diet ad libitum. At 68 weeks of age, incidental learning was tested by introducing shape cues that were redundant to the solution of a previously learned, two-choice, color discrimination. Removal of the color cues showed that the low-calorie monkeys had learned significantly less about the shape cues than had the controls. The basis for this incidental learning failure was then examined with an embedded-figures dicrimination, to measure attentional ability, and a novel stimulus substitution task, to measure curiosity. The groups did not differ in detecting embedded figures, but the low-calorie monkeys were significantly less likely than controls to select or handle novel stimuli that had been substituted for previously learned discriminative cues. It was concluded that undernutrition in infancy may induce a long-term strategy of only learning information which leads to an immediate reward, while suppressing the acquisition of information due to intrinsic curiosity.     

Environmental control and the perception of control

The perception of control may be established if an individual is provided with an opportunity to choose and if the outcome of the choice is moderately uncertain. In turn, perceived control has been shown to enhance motivation and performance. In the present experiment, the effects of uncertainty about environmental control were examined by measuring the speed with which choices were made. When control was implicitly provided, decision latencies were shorter than when control was either explicitly available or not available at all. Paradoxically, providing information about control may reduce uncertainty and thereby diminish the perception of control. The contribution of control and choice to the development of perceived control is discussed.This research is based on a thesis by the first author submitted in partial fulfillment of the master of science degree at Virginia Polytechnic Institute and State University and was supported by a grant from the U.S. Army Research Office to the second author.     

Duplex perception with musical stimuli

Duplex perception, a phenomenon previously demonstrated for speech stimuli, is demonstrated here for musical stimuli. In the first experiment, major and minor chords are produced by dichotic fusion of two simultaneous piano notes presented to one ear (perfect fifth) with a “natural” or “flat” single note presented to the opposite ear. Musically trained subjects perceive simultaneously both the single tone and a fused (major or minor) chord. The chords are labeled more consistently than the single notes, even though the fused chords differ solely in terms of the contralateral notes. In a second experiment, using pure tones in place of piano notes, other musically trained subjects individually exhibited categorical perception for either the fused chord or the single tones, but never for both types of stimuli. The duplex phenomenon is discussed in terms of its implications for its specific component modes of perception.     

The construction and validation of a juror bias scale

A questionnaire was constructed to measure individual differences in pretrial bias among jurors. The final Likert scale, called the Juror Bias Scale (JBS), contains 17 items—8 that reflect pretrial expectancies that defendants, in general, commit the crimes with which they are charged and 9 that reflect the value attached to conviction and punishment. The scale is internally consistent and test-retest reliable. Scores are uncorrelated with social desirability, moderately correlated with I-E control and belief in a just world, and more highly correlated with authoritarianism. In one validation experiment, student jurors were exposed to three trial presentations in a laboratory setting. Overall, subjects classified as prosecution biased were more conviction prone and adopted a less stringent standard of reasonable doubt. In a second study, community jurors watched one of two videotaped mock trials in a courtroom. Prosecution-biased subjects asserted a higher probability that the defendent committed the crime and rendered a higher percentage of guilty verdicts than defense-biased subjects for one of the two trials. JBS scores were unrelated to all demographic variables, but were significantly correlated with political views. The potential uses and limitations of the JBS are discussed.     

A microcomputer-based system for evoked-potential augmenting/reducing measurements

Evoked-potential measurements can readily be implemented on a microcomputer. We present as an example a system for obtaining an evoked-potential augmenting/reducing measure using the Apple II microcomputer. Specialized features of the PASCAL program and peripheral equipment are described.     

Does control of the environment enhance the perception of control?

It has been proposed that control over the environment increases the perception of control, thereby enhancing motivation. Revesman and Perlmuter (1981) found that when subjects were permitted to choose response terms to be learned on a paired-associate task, decision latencies were faster if the announcement of the desired option caused the screen upon which materials were printed to go blank. On the basis of the results of the present experiment, it was concluded that control of the environment does result in faster decision latencies, but that this effect occurs despite a decrease in the perception of control.     

Selective delayed alternation deficits in dominantly inherited olivopontocerebellar atrophy

In order to characterize more completely the nature of the frontal lobe-type cognitive changes in patients with dominantly inherited olivopontocerebellar atrophy (OPCA) we administered two tasks sensitive to frontal system dysfunction, delayed alternation (DA) and delayed response (DR), to 12 patients from one OPCA family. Affected members from this family have previously been shown to have a marked and widespread cerebral (including frontal) cortical cholinergic reduction as severe as that observed in Alzheimer's disease. Performance on DA, but not on DR, was significantly impaired in the OPCA patients compared to that in the controls. We suggest that the DA deficits in OPCA could be a consequence of a loss of cholinergic innervation to orbitofrontal or possibly temporal cortical areas and/or damage to the integrity of the cerebello-frontal neuronal connections.     

Life change and the sensation seeking motive

College undergraduates were administered the Life Experiences Survey, the Discomfort scale of the Psychological Screening Inventory, and the most recent version of the Sensation Seeking Scale. The findings did not replicate Smith et al.'s results concerning the role that sensation seeking plays in the relationship between negative life change and psychological distress. However, the data suggest that the sensation seeking motive is a causal variable that is predictive of recent life events that college students have experienced, and that future life-stress research should examine the occurence of controllable life events as a function of subjects' personality traits.     

Toward understanding sex differences in pay allocation: Agency,communion, and reward distribution behavior

This research examined the extent to which the personality characteristics of agency and communion are sex linked, and the extent to which differences in these orientations can account for sex differences in reward distribution behavior. In two studies, the agency and communion level of large samples of male and female undergraduates were assessed. As expected, males were more agentic and females were more communal. Moreover, when subjects who scored high or low on agency and high or low on communion were asked to allocate rewards between themselves and a co-worker, these personality differences were related to their allocation decisions. These results were used as the basis for discussing the role that sex-linked personality differences might play in distributive justice judgments.This article is an adaptation of a colloquium presentation at the meeting of the American Psychological Association, Los Angeles, August 1981. The research reported here was supported by NIMH grant MH29987-1, Goals, Motives, and Norms of Reward Distribution, and by NIMH Biomedical Research Support Grant from the College of Social Science, Michigan State University. The authors wish to thank Andrea Doughty for her valuable advice, and to gratefully acknowledge the help of Mark Teicher, Julie B. Klein, Sue Schnelbach, Pat Loepp, Barb Allen, Gavin Goodrich, Bob O'Hara, Kelly Bowen, Rod Hollenstein, Steve Schultz, and Mary Hurst.