Biomedical subjects

J G Corrigan

Publications and source records attributed to J G Corrigan.

5 recordsLinked to original sources

PubMed1983

Decision-time measures of sequential processing by mentally retarded and nonretarded adolescents and MA-matched children.

To eliminate the operation of organizational factors during crossmodal information processing, we compared mentally retarded adolescents, CA-matched nonretarded adolescents, and MA-matched children in a same-different decision task in which dyadic sequences were presented within and across the visual and auditory modalities. Decision times for correct "different" responses were greater for the CA-matched group than for the EMR and MA-matched groups, with all groups showing longest times for the visual-auditory dyads and shortest times for dyads in which both stimuli were visual. Differences between the auditory-auditory and auditory-visual dyads were negligible, and increments from visual-visual to visual-auditory dyads were significantly greater than from auditory-auditory to auditory-visual dyads in the EMR and MA groups. Results support a concept of greater visual dominance by the retarded and MA-matched groups rather than slower crossmodal attention switching, per se.

Adolescent↗

PubMed1982

Feedback effects on target search and velocity extrapolation by mentally retarded and nonretarded adolescents.

Equal-CA EMR and nonretarded adolescents stylus-tracked an intermittently disappearing rotary pursuit target with no feedback, auditory feedback, and visual feedback. With no feedback both groups demonstrated an approximately equal increase in distance errors during an 18-second period following disappearance of the target. With auditory and visual feedback, the nonretarded group remained closer to the target than with no feedback and closer than the retarded group under all three feedback conditions. Retarded subjects made more distance errors on a static search task requiring the use of auditory or visual feedback to locate a stationary target. Matching subsets of subjects from both groups on the basis of performance during the static search task eliminated differences in tracking performance during feedback. The ability to use feedback during static search predicted the ability to use feedback during rotary pursuit tracking.

Adolescent↗

PubMed1980

Effects of auditory feedback on velocity extrapolation by mentally retarded and nonretarded groups during rotary pursuit tracking.

Retarded adolescents, CA-matched nonretarded adolescents, and MA-matched nonretarded children stylus-tracked an intermittently disappearing rotary pursuit target with and without auditory feedback. Under the no-feedback condition, all groups demonstrated an almost linear increase in deviation errors over five successive 2-second intervals following disappearance of the target, with the retarded group showing a greater increase than did the CA-matched and MA-matched groups. Under the feedback condition, the CA-matched group reached an asymptote of target proximity 4 seconds after the target disappeared, whereas errors for the retarded and MA-matched groups continued to increase throughout the 10-second sample period. Performance of the retarded group with no feedback was interpreted as evidence for deficient velocity extrapolation, and failure of the retarded and MA-matched groups to stabilize proximity under the feedback condition was attributed to delayed response of the feedback.

Adolescent↗

PubMed1980

Self-paced vs. externally paced motor tracking by retarded and nonretarded persons.

An expectancy hypothesis of the psychological refractory period (PRP) was tested as an alternative to an arousal hypothesis to explain retarded persons' longer reaction times. Retarded adolescents, CA-matched nonretarded adolescents, and MA-matched nonretarded children tracked light stimuli presented under self-paced and externally paced conditions. Response latencies under both conditions were longer for the retarded and MA-matched groups, and all groups decreased latencies from the self-paced to externally paced conditions. Neither hypothesis was supported. We suggested that group differences were due to differences in the central delay effect of the PRP.

Adolescent↗

PubMed1979

Early selective visual experience and pattern discrimination in hooded rats.

The early visual experience of hooded rats was restricted to either vertical or horizontal stripes. In a discrimination task pairing a gray surface and stripes of either the same orientation or an orientation orthogonal to that experienced during rearing, the rats made significantly fewer correct choices with the orthogonal orientation. However, the relatively lower overall performance of the vertically reared-horizontally tested animals was a major factor in the main effect of testing condition. We conclude that functional of the rat visual system through early selective visual experience is possible.

Animals↗