CLASSIFICATION IN CATEGORY CONJUNCTION: THE LOGIC OF OVEREXTENSION
Fintan Costello · International Journal of Artificial Intelligence Tools · 2005
Traditional approaches to semantics give a set-theoretic account of category conjunction, in which an item will be a member of a conjunction A&B only if it is a member of the single category A and a member of the single category B. However, a number of studies have found that people do not follow this set-theoretic account when classifying items in certain natural-language conjunctions. For example, Hampton1 found that while people tend to classify 'toucans' as non-members of the single category 'pet', they classify 'toucans' as members of the conjunction 'pet bird'. This paper describes a general approach to category conjunction that gives a logically consistent explanation for the occurrence of overextension in these conjunctions. The paper also describes a computational model implementing this approach, and an experiment using conjunctions of controlled, laboratory-learned categories to test this model. This computational model gave a good fit to both classification and overextension results in the experiment. The approach to conjunction implemented in this model may provide a useful tool for AI models of classification, allowing them to reason about category conjunction in a way that reflects human reasoning.