Orientation discrimination in WS 2
Abstract
The visuo-spatial perceptual abilities of individuals with Williams syndrome
(WS) were investigated in two experiments. Experiment 1 measured the ability of
participants to discriminate between oblique and between nonoblique orientations.
Individuals with WS showed a smaller effect of obliqueness in response time, when
compared to controls matched for non-verbal mental age. Experiment 2 investigated
the possibility that this deviant pattern of orientation discrimination accounts for the
poor ability to perform mental rotation in WS (Farran et al., 2001). A size
transformation task was employed, which shares the image transformation
requirements of mental rotation, but not the orientation discrimination demands.
Individuals with WS performed at the same level as controls. The results suggest a
deviance at the perceptual level in WS, in processing orientation, which fractionates
from the ability to mentally transform images.