Young children usually make similarity-based attribution concerning properties of living things, i.e., attributing human properties to the target object according to its similarity to people. They do this because they are very familiar with human beings while they are novices in most other domains. This similarity-based attribution tends to shift toward a category-based one with age. However, the age at which this shift occurs varies with the type of target property. For anatomical/physiological properties (e.g., bones) which are explicitly dealt with in school biology, the shift occurs early. For mental properties (e.g., feeling), which are not directly taught in school, the shift occurs late if at all. Even adults in part rely on similarity-based attribution for mental properties. Implications of these ideas for studies of animism are discussed.