Biomedical subjects

W A Hershberger

Publications and source records attributed to W A Hershberger.

13 recordsLinked to original sources

PubMed1999

Haptic estimates of discordant visual-haptic size vary developmentally.

In two size-conflict experiments, children viewed various squares through a reducing (1/2) lens while manually grasping them through a hand-concealing cloth. Then, using either vision or touch, they selected a match from a set of comparison squares. Forty 6-, 9-, and 12-year-olds participated in Experiment 1. Vision dominated the visual estimates of all three age groups; however, for the haptic estimates, the dominant modality varied developmentally: Vision dominated the 6-year-olds' haptic estimates, whereas neither modality dominated the 9-year-olds' haptic estimates, and touch dominated the 12-year-olds' haptic estimates. In Experiment 2, 24 six-year-olds were tested, as in Experiment 1; however, half of them were shown the size-distorting effects of the lens just prior to testing. Although this reduced the visual dominance of their haptic estimates, the effect was weak and short-lived. The haptic dominance seen in the data of the 12-year-olds was conspicuously absent.

Analysis of Variance↗

PubMed1998

Visualizing the perisaccadic shift of spatiotopic coordinates.

A point light source flickering on and off during a horizontal saccade projects a horizontal array onto the retina. The apparent visual direction of the tail end of the perceived (phantom) array reflects the amount of perisaccadic shift of spatiotopic coordinates that has been completed by the end of the saccade. Four men, saccading 8 degrees to the right across a flashing light, judged the horizontal visual direction of the left (tail) end of the phantom array relative to the left end of a standard 8 degrees array that had projected an image onto the retina before the saccade began. On average, the left ends appeared to be aligned when the last flash in the phantom array was imaged on the retina 7.4 degrees to the right of the image of the left end of the standard array. This result implies that the shift of spatiotopic coordinates is virtually complete by the end of the saccade.

Adult↗

PubMed1996

Touch dominates haptic estimates of discordant visual-haptic size.

Observers (72 college students) estimated the size of plastic squares that they held in their fingers and simultaneously viewed through a reducing lens that halved the squares' visual size. The squares were grasped from below through a cloth that prevented direct sight of the hand. Each estimate was a match selected later, either haptically or visually, from a set of comparison squares. Vision dominated the visual estimates and touch dominated the haptic estimates, whether or not the observers knew in advance which type of estimate they would be asked to make. Neither modality inherently dominates perceived size.

Adult↗

PubMed1994

Timing the shift in retinal local signs that accompanies a saccadic eye movement.

The phantom array was used to probe the time course of the shift in retinal local signs that accompanies a saccadic eye movement. The phantom array materializes when one saccades in the dark across a point light source blinking 120 times per second. One sees a stationary array of flashes--the first materializes discretely near the intended endpoint of the saccade, and subsequent flashes materialize progressively closer to the actual position of the blinking light. Four trained observers indicated the perceived location, relative to the phantom array, of a 1-msec marker flash (M) produced by two LEDs (light-emitting diodes) that vertically bracketed the blinking light. The marker was seen as spatially coincident with the first flash when it flashed 80 to 0 msec before the saccade, and was seen as spatially coincident with either the first flash or the actual position of the blinking light when it flashed more than 80 msec before the saccade, indicating, respectively, that the shift is presaccadic and rather abrupt.

Adult↗

PubMed1989

Development of visual attention: a stereoscopic view.

Five-year-olds, 8-year-olds, and adults (20 each) tachistoscopically viewed random-dot stereograms containing either uniform depth or an elevated disk whose perimeter fell 1.5 degrees, 2.5 degrees, or 4 degrees beyond fixation. When subjects were forewarned as to the size of the disk to look for (precued trials), signal detection improved (d' increased) for all three groups, and 5-year-olds improved the most. Without forewarning (self-cued trials), the 5-year-olds performed more poorly than the other two groups, which performed alike. Although young children are able to allocate their visual attention selectively, they do not appear to deploy it as quickly or as effectively as their elders when the focus of attention is theirs to choose.

Adult↗

PubMed1988

Effects of impaired hearing and favorable vs. unfavorable personal feedback on negative emotional reactions.

Eighty college females listened to one of four taped conversations, which they were led to believe were personality evaluations of themselves. The content of the evaluations varied in feedback, which described either strengths or weaknesses in adjustment, and in form, in that each recording was either completely intelligible or partially unintelligible to simulate normal and impaired hearing, respectively. The emotional reactivity of the subjects was assessed with several psychometric instruments once before and again immediately after they listened to the tapes; the pre/post difference scores reflected the negative emotions elicited by the experimental manipulations. Factorial analyses of variance yielded significant main effects for each variable, hearing and feedback, but no interaction. Anxiety, depression, negative attribution, and paranoid reactions were increased by both impaired hearing and unfavorable feedback, and their adverse effects were independent and additive.

Adaptation, Psychological↗

PubMed1976

The influence of early auditory experience on later auditory and tactual variation seeking in the rat.

Albino rats were raised under 1 of 4 conditions of auditory stimulation from 22-35 days of age. At 40 days, preferences for auditory and tactual variation were assessed in separate runway tests. Results were analyzed in a split-plot design for each of 2 measures of variation seeking. Subjects experiencing more-variable early stimulation scored higher than subjects receiving less-variable stimulation on 1 measure of variation-seeking and lower on the 2nd measure. The effect was intermodal since these results were obtained for tactual as well as auditory variation seeking.

Acoustic Stimulation↗

PubMed1976

Conflicting motion perspective simulating sinultaneous clockwise and counterclockwise rotation in depth.

Motion projections (pictures) simulating a horizontal array of vertical lines rotating in depth about its central vertical line were observed by 24 college students who rotated a crank handle in the direction of apparent rotation. All displays incorporated contradictory motion perspective: Whereas the perspective transformation in the vertical (y) dimension stimulated one direction of rotation, the transformation in the horizontal (x) dimension simulated the opposite direction. The amount of perspective in each dimension was varied independently of the other by varying the projection ratio used for each dimension. We used the same five ratios for each dimension, combining them factorially to generate the 25 displays. Analysis of variance of the duration of crank turning which agreed with y-axis information yielded main effects of both x and y projection ratios but no interaction, revealing that x- and y-axis motion perspectives mediate kinetic depth effects which are functionally independent.

Depth Perception↗

PubMed1974