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Ralf Goertz

Publications and source records attributed to Ralf Goertz.

3 recordsLinked to original sources

Do children with developmental dyslexia show a selective visual attention deficit?

The authors investigated the performance of children with developmental dyslexia on a number of visual tasks requiring selective visual attention. Dyslexic children did not show the overestimation of the left visual field (pseudo-neglect) characteristic of normal adult vision. The performance of dyslexic children in texture segmentation and feature search tasks was identical to that of control children matched for age, gender and intelligence. However, when tested on conjunction tasks for orientation and form, dyslexic children showed shorter reaction times and a dramatically increased number of errors. Differences between the two groups decreased with increasing age. These results suggest that children with developmental dyslexia present selective deficits in visual attention.

Adolescent↗

Children with developmental dyslexia show a left visual "minineglect".

We investigated the performance of children with developmental dyslexia on a visual line bisection task. Dyslexic children did not show the overestimation of the left visual field (pseudoneglect) characteristic of normal adult vision. These results suggest that children with developmental dyslexia present selective deficits in visual attention, probably involving neural structures located in the right posterior parietal cortex.

Adult↗

Hemispheric differences in the recognition of possible and impossible objects.

Three experiments using a visual half-field technique were conducted to address the question of lateralised processing of three-dimensional aspects of visual stimuli. We used drawings of "possible" and "impossible" triangles and quadrilaterals. In one condition subjects had to decide whether these stimuli were possible (i.e., the depicted figures could exist in the three-dimensional world) whereas in the second condition the task was to distinguish between triangular and quadrangular shapes. All experiments revealed an interaction of task and visual field on discrimination indices (d') suggesting a dissociation of the processing of two- and three-dimensional aspects of visual stimuli. These results are discussed with respect to known perceptual differences between the cerebral hemispheres.

Adult↗