Mental Rotation of Viewpoint-Dependent/Independent Features in Children With Difficulty in Japanese Kanji Writing

This study examined viewpoint-dependent and viewpoint-independent visual cognitive processes in children of normal intelligence (mean age=9.8 years) who have difficulty in Japanese Kanji writing. A mental rotation task in which the stimuli consisted of two ice-cream cones with three differently colored scoops of ice cream was used. Children were asked to judge whether the two stimuli, one upright and one rotated, were the same or different. Ice-cream cones were either identical, mirror images, or non-mirror images. We found that children with difficulty in Kanji writing showed no impairment for identical and non-mirror images and only exhibited lower accuracy scores when stimuli were mirror images. Since children could complete mental rotation in the identical condition and could find the unique features in the non-mirror images condition, their viewpoint-dependent and viewpoint-independent systems may be intact. However, they had deficits in mirror image perception. These may be one of the factors underlying reversal errors in these children.