Hemisphere specialisation and categorical spatial relations representations

Hemisphere specialisation in two- and three-dimensional categorical spatial relations tasks was investigated using normal adult subjects. In Experiment 1, subjects were asked to indicate the rightmost (or leftmost) card in stimuli consisting of three overlapping cards as quickly and as accurately as possible. The results showed no significant visual field difference in either response times or error rates. In Experiment 2, stimuli identical to those of Experiment 1 were used and subjects were asked to indicate the card most to the front or the one most to the back. The error rates showed a strong tendency towards a left visual field advantage in accuracy while no visual field difference was shown in response times. Based on these findings, relations between the hemisphere specialisation and categorical spatial relations encoding subsystems in Kosslyn's (1987) model of visual information processing are discussed.