COMPARATIVE-ASSESSMENT OF DISTANCE PROCESSING AND HEMISPHERIC-SPECIALIZATION IN HUMANS AND BABOONS (PAPIO-PAPIO)

This comparative study explored the ability to process distance and it s lateralization in humans and baboons. Using a conditional matching-t o-sample procedure in a divided-held format, subjects had to decide wh ether or not the distance between a line and a dot belonged to a short - or a long-distance category. Experiments 1, 2, and 4 demonstrated th e ability of baboons to process and categorize distances. Moreover, hu mans showed better distance processing for right visual field/left hem isphere presentations than for left visual field/right hemisphere (LVF -RH) displays (Experiments 1-2). The same bias was found in baboons (E xperiment 1), but in a weaker way. In Experiment 3, naive human indivi duals were tested and the difficulty of the discrimination was enhance d. There was a LVF-RH advantage which vanished with practice. Results are discussed by referring to theories (i.e., Kosslyn, 1987) of visuos patial processing for coordinate and categorical judgments. (C) 1998 A cademic Press.