Abstract
Thibaut and Dupont (1997) replicated a dissociation between
categorization and similarity obtained by Rips (1989). In his
experiment, Rips found that a stimulus half-way between a pizza and a
quarter was categorized as a pizza but was rated as more similar to a
quarter. In their experiment, Thibaut and Dupont (1997) presented
unknown stimuli composed of a non salient necessary feature combined
with a salient characteristic feature. Participants categorized the
stimuli on the basis of the necessary feature and made their
similarity judgments on the basis of the characteristic
feature. However, Thibaut and Dupont failed to obtain this
dissociation in one of their experimental conditions. They
hypothesized that the origin of this failure was to be found in the
fact that subject did not notice the association between the
characteristic feature and the corresponding category. In the present
paper, by introducing a free sorting task, subjects produced the
dissociation in the condition in which they did not produce it in
Thibaut and Dupont. The results are discussed in terms of the role of
necessary and characteristic features. I also propose a distinction
between categorization and similarity judgments, and an interpretation
of the dissociation in terms of the feature space.
Jean-Pierre Thibaut