2007 年 25 巻 2 号 p. 281-282
Two experiments investigated the visual processing of hierarchical stimuli by chimpanzees. Using a delayed matching-to-sample (DMTS) task, five chimpanzees were tested for their perceptual dominance of global or local information in hierarchically designed figures which consisted of global configurations and local elements. The results of the first experiment displayed individual differences in global-local processing of the figures. Two of the chimpanzees exhibited a advantage for local level processing and the others exhibited an advantage for processing global shape. The results of the second experiment revealed that manipulation of the density of local elements affected the performance of the three chimpanzees who had global precedence but did not affect the performance of the other two chimpanzees who had local precedence. These results suggest that a precedence for global or local visual processing in chimpanzees is not determined a priori but depends on strategies which are learned individually to solve a given task.