The Time-Course of the Use of Background Knowledge in Perceptual Categorization

We examined the time-course of the utilization of background knowledge in perceptual categorization by manipulating the meaningfulness of labels associated with categories and by manipulating the amount of time given to subjects to make a categorization decision. Extending a paradigm originally reported by Wisniewski and Medin (1994), subjects learned two categories of children's drawings that either were given standard labels (drawing by children from group 1 or group 2) or were given theory-based labels (drawings by creative or noncreative children); meaningfulness of the label had a profound effect on how new drawings were categorized. Half of the subjects were given unlimited time to respond, the other half of the subjects were given a quick response deadline; speeded response conditions had a relatively large effect on categorization decisions by subjects given the standard labels but had a relatively small effect on categorization decisions by subjects given the theory-based labels. These results suggest that background knowledge may have its influence at relatively early stages in the time-course of a categorization decision.