A behavioral link between the oculomotor and cardiovascular systems

Although the eyes and the heart serve very different purposes, each receives autonomic innervation. Capitalizing on recent theoretical and technological innovations in the understanding and assessment of oculomotor and cardiovascular behavior, three experiments measured behavioral covariation between the oculomotor and cardiovascular systems. Measures of dark focus and dark vergence indexed oculomotor tone, and the spectral decomposition of variations in heart rate indexed cardiovascular control mechanisms. In Experiment 1, individual differences in cardiovascular parameters could predict individuals’ dark vergence (R²=.806) but not their dark focus (R²=.404). In Experiment 2, the same parameters were measured from subjects who experience either panic attacks (n=11) or blood phobia (n=9). Heart rate was positively correlated with dark vergence and the two subject groups were separable based on both oculomotor and cardiovascular variables. Using a within-subjects approach, Experiment 3 found that both dark vergence and dark focus tended to be nearer during sympathetic dominance of the heart than during parasympathetic dominance, within-subjects variations in cardiovascular parameters could predict dark focus, and between-subjects variations in interbeat intervals could predict dark vergence. Shared patterns of autonomic activation may be responsible for this eye-heart link.     

Measuring and predicting the effects of alcohol consumption on contrast sensitivity for stationary and moving gratings

Contrast sensitivity was measured for 12 healthy young males while sober, after ingestion of an alcohol placebo, and after ingestion of alcohol (95% grain alcohol; mean estimated blood alcohol level = .088%). Observations were made for both stationary gratings and gratings that traveled through a circular path and required pursuit eye movements. The significant alcohol-related reduction in contrast sensitivity was 2.6 times greater for moving (.29-log-unit reduction) than for stationary gratings (.11-log-unit reduction). The loss in contrast sensitivity for the moving gratings of high spatial frequency (12 cpd) was particularly severe (.37 log unit). Estimated blood alcohol level was correlated with the loss in contrast sensitivity for moving gratings (r = .61), but not with the loss for stationary gratings. Estimated blood alcohol level was strongly correlated with the difference between the loss in contrast sensitivity to moving and stationary gratings (r = .75). These results are consistent with reports that alcohol consumption degrades the ability to make pursuit eye movements. Subjects’ perceived intoxication level was not a reliable predictor of any index of visual performance.     

Practice effects for visual resolution in the periphery

Resolution thresholds at 0° (fovea), 20°, 40°, and 60° along the horizontal meridian of the temporal visual field revealed a characteristic degradation in visual resolution with increasing stimulus eccentricity. However, substantial individual differences were found, particularly at 40° and 60° of eccentricity. Dramatic improvements in peripheral visual resolution occurred over a period of 11 practice sessions, with the time course of practice effects increasing for greater visual field eccentricities. Improvements with practice reduced, but did not eliminate, individual differences. The present visual resolution findings are compared to previous studies of peripheral motion detection and increment thresholds.     

Practice,refractive error,and feedback as factors influencing peripheral motion thresholds

Motion thresholds were determined in the fovea and in the horizontal peripheral meridian under conditions of practice, correction of refractive error, and feedback. While foveal determinations did not change significantly, peripheral motion thresholds were lowered for all conditions. Both practice and practice with feedback produced significantly better motion discrimination, these effects showing a longevity of several months. However, the largest improvement resulted from correction of peripheral refractive error, which also reduced individual differences. This suggests that peripheral sensitivity to movement is ordinarily limited primarily by dioptric rather than neural factors. Implications for perceptual learning and peripheral vision research are discussed.     

Dissertation research in school psychology: 1967–73

Reports the results of a categorical analysis designed to ascertain the kinds of dissertation research completed for the doctoral degree in school psychology during the years 1967–1973. Major areas of research emphasis were delineated although trend analysis revealed no significant trends over the seven-year period.     

Factors affecting the magnitude of the Ponzo perspective illusion among the Baganda

The magnitude of the Ponzo perspective illusion, utilizing stimuli with varying amounts of context, was determined for a population of Ugandan villagers. The subjects were classified as two-dimensional, three-dimensional, or mixed perceivers based upon their verbal responses to photographs portraying symbolic depth cues. The illusion magnitude among those subjects classified as three-dimensional was similar to that of college observers who demonstrate an increase in illusion magnitude with increasing background context. The two-dimensional observers’ responses were similar to those of villagers tested previously, showing no significant increase for the same conditions. The role of two-dimensional flatness cues was eliminated on the basis of a control experiment. The data are interpreted as reflecting the operation of a. cognitive factor determining responsiveness to symbolic depth cues in two-dimensional reproductions.     

Exploring numerical proportions in a unique context: The group support systems meeting environment

This paper reports the results of a study examining issues of group gender composition in a meeting setting employing group support systems (GSS). Research examining the effects of numerical proportions on group behavior has traditionally been conducted in settings where use of technology by groups is minimal. This research, however, examines the impact of varying group gender composition on brainstorming, social interaction patterns, and attitudes when technology is employed to facilitate and structure group process. In this setting, we find no gender-related differences in computer-based brainstorming. In the accompanying oral discussions, however, males display a higher proportion of task-related answers than females and uniform groups express more maintenance behavior than groups consisting of mixed genders. Our findings also show that uniform gender groups perceive greater participation in the decision process than skewed groups. Despite these gender-related differences, we found relatively little support for Kanter's Numerical Proportions Model in a GSS setting, given the range of measures explored in this study.