| | |
Summary: In the study of category learning, it is often desirable to
design tasks in which participants use a particular type of
decision strategy. This goal is typically pursued by sim-
ply instructing participants to use a specific strategy (see,
e.g., Allen & Brooks, 1991) rather than constraining the
design of the categorization task. We propose that specify-
ing the amount of overlap between contrasting categories
may provide a simple method to constrain decision strat-
egy. Category overlap historically has been manipulated
to control task difficulty, and was not thought to affect the
qualitative nature of the decision strategy used by partici-
pants.This article presents the results of three experiments
that challenge this widely held view.
Category learning has been investigated using tasks that
vary considerably with regard to stimulus materials, cate-
gory structures, and procedure. For example, in some tasks,
the entire stimulus set comprises just nine exemplars (e.g.,
Medin & Schaffer, 1978), whereas in other tasks, a single
category comprises hundreds of exemplars (e.g., Ashby &
Gott, 1988). Despite this variability, in the majority of tasks,
|
