On the role of reduced auditory feedback and kinesic self-stimulation during Stroop Color-Word performance1

Feedback from one's own voice provides important vocal–motor cues for effective cognitive processing. Reduction of such feedback is known to disturb such functioning. Work in our laboratory has shown that kinesic self-stimulation also plays an important role in cognition, and appears to regulate the focusing of attention under conditions of distraction. The present study investigated the effects of both auditory feedback and kinesic self-stimulation in the regulation of cognitive interference during performance of the Stroop Color-Word Task. Twelve subjects were tested on the Stroop task under conditions of normal and occluded hearing. Kinesic self-stimulation and response errors during color-word performance were recorded on video tape. The findings indicated that not only did self-stimulation increase when voice feedback was reduced, but that this increase was associated with a reduction in specific types of color-word performance errors. Individual differences revealed that high kinesic responders made significantly fewer errors in task performance than did low kinesic responders. Results were interpreted as revealing a kinesic feedback mechanism which has adaptive significance in regard to self-editing when auditory feedback is reduced.     

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.     

On the statistics of vision: The Julesz conjecture

This paper describes a class of random patterns which have the same first-, second-, and third-order statistics as coin tossing, but are visually different. The patterns are counterexamples to a conjecture of Julesz that all the eye can discriminate is first- and second-order statistics.     

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.