On the equivalence of superordinate concepts.

Psychological studies of superordinates have generally treated them as equivalent. However, many languages distinguish mass superordinates (e.g., clothing) from count superordinates (e.g., vehicle). In the present paper, experimental evidence is presented which suggests that the two types of superordinates are conceptually distinct as well. One study showed that the members of mass superordinates more often co-occur. A second study showed that people more often interact with the members of mass superordinates in temporal proximity whereas people primarily interact with single members of count superordinates on a specific occasion. Also, properties that characterize an individual are a more salient aspect of count superordinates. These findings imply that mass superordinates refer to unindividuated groups of objects, united by spatial and functional contiguity. Two other studies supported this hypothesis by showing that the class inclusion relation between a single object and a category is stronger for count superordinates. Taken together, the findings suggest that mass superordinates are not true taxonomic categories. We relate the findings to previous views of superordinates and to the count/mass distinction in general.