The Presence and Absence of Category Knowledge in LSA

How much information about meaning is contained in the statistical structure of the environment? LSA is a theoretical and practical tool that is challenging previous notions about what is contained in the statistical structure of the environment. This paper examines what kind of category knowledge can be obtained from the environment using LSA. In particular, two experiments are conducted with LSA to test what kind of category structure it embodies. LSA ratings about the relatedness of categories to their properties are compared with human judgments regarding the centrality of properties to the categories. LSA is found to capture aspects of property centrality for some object and event categories. However, it is found to only capture those aspects related to typicality: how often do members of the category have that property? LSA fails to capture other aspects of centrality that can be found in human category judgments. Thus, it appears that humans do bring other constraints to bear in shaping their categories.