抄録
Categorization is an ability to group individuals into different classes. There are several levels of categorization. At the most concrete level, all members of the category share common physical attributes that differ from other categories. The higher level, the fewer common attributes between members of the group. In humans, categorization is fundamental in language, prediction, inference, decision making. In animals, the ability to categorize has also been proposed. The present experiment tested ability of categorization in long-tailed macaques (Macaca fascicularis). We used facial photos of humans and animals for the stimuli. First, we tested their ability to classify humans and macaques into separate groups. Second, we tested their ability to discriminate their conspecific from other macaques. And the last, we tested whether the subjects were able to discriminate non-human animals from humans. In all of these experiments we found that the subjects showed high performance in categorizing objects, even when we discarded details of visual informations, such as color and local shapes. The results suggested that the subjects could create a more abstract category based on logical relations. Thus, we concluded that M. fascicularis were able to perform multiple levels of categorization.
