Effects of the Ebbinghaus illusion on children's perception and grasping.
We investigated the development of the Ebbinghaus illusion in children's perception and grasping. A previous study (Hanisch et al. 2001) had reported negative illusion effects on 5- to 12-year-olds' grasping as compared to their perception. We attempted to replicate this finding and to test different hypotheses based on a direct influence of the context elements on the trajectories of the fingers which could explain this reversal of the illusion effects. For 5- to 7- and 9- to 11-year-olds we observed the classical illusion effects in perception. Illusion effects were perfectly similar for perception and grasping in 9- to 11-year-olds, while there was a non-significant trend toward smaller illusion effects in grasping for the 5- to 7-year-olds. This could be due to a slightly different effect of the illusion on younger children's grasping. However, it seems clear that there are no qualitative changes, as a reversal of the illusion effects in grasping of younger children. Finally, we show that our grasping data conform well to the motor literature for children's grasping, thereby strengthening our conclusions.
Justus-Liebig-Universität Giessen, FB06 psychologie und Sportwissenschaften, Otto-Behaghel-Strasse 10 F, 35394, Giessen, Germany. thomas.duemmler@psychol.uni-giessen.de
Thomas
T
Duemmler
Volker H
VH
Franz
Bianca
B
Jovanovic
Gudrun
G
Schwarzer
D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D005260:Female; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D009903:Optical Illusions / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods*; D014796:Visual Perception / Q000502:physiology*