Pm. Vishton et al., Comparing effects of the horizontal-vertical illusion on grip scaling and judgment: Relative versus absolute, not perception versus action, J EXP PSY P, 25(6), 1999, pp. 1659-1672
Citations number
46
Categorie Soggetti
Psycology
Journal title
JOURNAL OF EXPERIMENTAL PSYCHOLOGY-HUMAN PERCEPTION AND PERFORMANCE
The discovery that the prehension component of an open-loop, two-fingered r
each is largely immune to certain salient pictorial illusions has been used
to suggest that humans possess 2 distinct visual systems, 1 that subserves
perceptual judgment and 1 that mediates visually controlled action. In thi
s article, the authors present evidence that suggests that the critical dis
tinction is not that of reaching and judgment but of relative and absolute
perception. Experiment 1 extends the findings of S. Aglioti, J. F. X. DeSou
za, and M. A. Goodale (1995) and suggests that the manual prehension compon
ent of open-loop reaching is affected by the horizontal-vertical illusion t
o a much smaller degree than perceptual size judgments. In Experiments 2 an
d 3, however, when perceptual size judgment is directed at a single element
of the display, this difference vanishes. Experiment 4 demonstrates that g
rip scaling is strongly affected by the illusion when a single reach is sca
led to both the horizontal and vertical components of a triangular figure.