Biomedical subjects

J O Adams

Publications and source records attributed to J O Adams.

3 recordsLinked to original sources

PubMed1987

Dichaptic-visual form matching in adults.

Although previous visuo-dichaptic matching studies report hemispheric asymmetries in spatial-form perception, more recent studies have failed to support these findings. Three cross-modal matching experiments examined hemispheric asymmetries in adult spatial-form matching. In the first experiment, subjects simultaneously felt two eight-point or 12-point tactile shapes patterned after Vanderplas and Garvin (1959) for four seconds and were then required to identify both shapes from a visual response array. Results showed subjects were significantly better identifying eight point shapes. A marginally significant feeling hand by pointing hand interaction indicated that recognition accuracy was higher when shape ipsilateral to the pointing hand was identified. In the second experiment, only one of the two tactile shapes had to be identified from the visual array. Results showed a significant interaction between complexity and feeling hand, where the left and right feeling hands were respectively better at identifying 12-point and eight-point shapes. The third experiment was an attempt to more directly examine the Witelson (1976) experiment using her spatial-form stimuli. Results showed no significant laterality nor stimulus-response compatibility effects. These findings are discussed in terms of cerebral asymmetry and stimulus-response compatibility models.

Adult↗

PubMed1987

Hemispheric asymmetries for complex visual patterns.

Three tachistoscopic studies examined the laterality of spatial-form perception in normal adults using randomly generated eight-point and 12-point patterns (Vanderplas & Garvin, 1959) as the lateralized stimuli. In the first study of recognition accuracy, 36 subjects were tested in a partial replication of Fontenot. No laterality effects were found, and over-all recognition was better for the more complex 12-point patterns. In a second similar study with 20 subjects, the lateralized stimulus was followed by a central masking pattern. A left-hemisphere superiority for recognition and better over-all recognition for more complex patterns was obtained. These data do not support Fontenot's report of right-hemisphere superiority in complex visuospatial processing. Given these diverse findings, a reaction time study using mental rotation was conducted using the same patterns to determine whether latency would reflect accuracy of recognition. Twenty-six subjects judged whether a rotated lateralized test pattern was the same or different from a central target pattern. Measures of both latency and accuracy were separately assessed. No main effect of visual field was obtained on either measure. These studies suggest that the nature of hemispheric involvement in spatial form perception is far from resolved.

Adult↗

PubMed1986

Laterality of cross-modal spatial processing.

This study examined the laterality of spatial-form perception in normal adults using a cross-modal matching paradigm involving visual and tactile processing. Randomly generated eight-point and 12-point Vanderplas and Garvin (1959) patterns were used as the stimuli. In a visual-to-tactile task, a lateralized visual pattern was followed immediately by a haptic task requiring subjects to discriminate which of two simultaneously felt shapes matched the visual pattern. In a tactile-to-visual task, subjects decided which of two simultaneously felt shapes matched a lateralized visual pattern presented after haptic manipulation. There were no main effects for laterality or for sex differences. Matching accuracy was better in the visual-to-tactile task and for less complex stimuli. A visual field by feeling hand interaction showed best recognition accuracy when visual-feeling hand combinations on the same side of the body were used in the two matching tasks. These data reflect a stimulus-response compatibility explanation of spatial-form perception that is consistent with a behavioral and not a cerebral asymmetry model.

Adult↗