Abstract

Which criteria underlay the way objects are grouped together to give rise to categories? In this paper, the three main answers provided by recent research will be reviewed: a) "rules" drive the categorization process; b) "theories" about world help shaping categories; c) "similarity" is the glue linking entities into categories. However, none of these answers by itself can explain the experimental evidence on categorization. It is precisely the fundamental variability of categories that requires more sophisticated interpretations like those provided by mixed models that will be discussed as well.