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Biomedical subjects

J C Dill

Publications and source records attributed to J C Dill.

7 recordsLinked to original sources
PubMed1998

Social evaluation influence on cardiovascular response to a fixed behavioral challenge: effects across a range of difficulty levels.

Participants performed five memory tasks--ranging in difficulty from very low to very high--under public or private conditions. The publicity and difficulty variables interacted to determine systolic pressure and heart rate responses during performance. Where performance was public, responsiveness on the parameters increased with difficulty to a point and then dropped; where performance was private, responsiveness was relatively low at all difficulty levels. Diastolic pressure responses were configured similarly, although in that case the interaction was not reliable. Findings corroborate and extend results from a previous study, argue against some explanations of those results, and strengthen the case for a recent active coping analysis of cardiovascular audience effects. Findings also strengthen the case for a broader model of effort and cardiovascular response, which has potential for advancing our understanding of a range of phenomena and processes related to behavior and health.

Adult↗
PubMed1994

Behavioral and characterological attributional styles as predictors of depression and loneliness: review, refinement, and test.

The literature on self-blame and depression reveals two interrelated problems. First, although R. Janoff-Bulman's (1979) conceptualizations of self-blame are clear, empirical operationalization is difficult and has resulted in approaches that do not capture the richness of the constructs. Second, past research has produced inconsistent findings. A comprehensive literature review revealed that the inconsistencies are related to the method of assessing attributions. A correlational study designed to more accurately represent the self-blame conceptualization revealed that both behavioral and characterological self-blame contribute uniquely to depression and loneliness. Supplementary results regarding circumstantial attributions and regarding attributional styles for success were presented. Empirical issues regarding possible methodological refinements and effect size, as well as the value of categorical approaches to the study of attributional style were discussed.

Character↗
PubMed1993

Blood pressure responses and incentive appraisals as a function of perceived ability and objective task demand.

This experiment examined the role perceptions of ability may play in determining the impact of task demand on cardiovascular responses indicative of active coping. Subjects first performed a scanning task and received feedback indicating that they had either low or high scanning ability. They then were presented with the opportunity to earn one of two incentives by attaining either an objectively low or objectively high standard of performance on a second scanning task. Immediately prior to and during the 1-min performance period, systolic and diastolic blood pressure responses were greater in the difficult standard condition than in the easy standard condition for those who received high-ability feedback but were somewhat diminished in the difficult standard condition as compared with the easy standard condition for those who received low-ability feedback. Whereas high-ability subjects tended to have less pronounced pressor responses than did low-ability subjects when the second task was objectively easy, they had more pronounced pressor responses than low-ability subjects when the second task was objectively difficult. Analysis of goal attractiveness ratings obtained just prior to task performance showed a general correspondence between subjects' anticipatory blood pressure responses and their appraisals of the incentives. Implications for several lines of investigation are discussed.

Adaptation, Psychological↗
PubMed1992

Interactive effects of difficulty and instrumentality of avoidant behavior on cardiovascular reactivity.

College-aged subjects performed 35 trials of an easy or difficult digit-recognition task. Half were told that a good performance would ensure a high chance of avoiding a blast of noise, and half were told that a good performance would ensure a low chance of avoiding the noise. Results indicated that heart rate and systolic blood pressure reactivity were higher in the difficult condition than in the easy condition only when the probability of avoiding the noise (given success) was high. When the probability of avoiding the noise (given success) was low, heart rate and systolic responsivity were low regardless of task difficulty. It also was found that (1) performance quality was poorer overall among difficult subjects than among easy subjects, and (2) that the difference in performance quality between the easy and difficult groups was somewhat (not significantly) greater in the low-probability conditions than in the high-probability conditions. Major findings are considered in terms of Obrist's reasoning regarding the psychophysiological consequences of active coping and a motivational model by Brehm, which specifies conditions under which individuals will be more and less task engaged.

Adaptation, Psychological↗
PubMed1969

Fundamental properties of intensity, form, and motion perception in the visual nervous systems of Calliphora phaenicia and Musca domestica.

Several classes of interneurons in the optic lobes and brain of the insects, Musca domestica and Calliphora phaenicia, have been studied in detail. Visual stimuli have been categorized on the basis of the properties of intensity, form, and motion. Response characteristics of the classes of neural units are described with respect to these three classes of visual stimuli. While those units that detect motion in select directions have a tonic response, form detection units have a phasic response only. Through correlation of the responses of these classes with visual stimuli, it is shown that these units integrate the responses of other units which have very small visual fields. The small-field units are presumed to integrate the output of a small group of adjacent retinula cells and to respond differentially to intensity, form, and motion. It is shown that the response of both form and motion detection units is independent of the direction of pattern intensity gradation. As a consequence of this independence, it is further shown that failure to detect motion properly must start at a spatial wavelength four times the effective sampling station spacing rather than twice as has been predicted previously.

Animals↗