Abstract
Four pigeons were tested in concurrent basic-level (cars, chairs, flowers, or people; four-key forced-choice procedure) and superordinate-level (natural or artificial; two-key forced-choice procedure) categorization tasks. Prior research revealed dissociation between natural and artificial stimuli: the discrimination of cars and chairs was acquired faster at the basic level than at the superordinate level, but the opposite was true for people and flowers. This dissociation between natural and artificial stimuli appeared in later stimulus control tests (e.g., blurring and scrambling). The results presented here are derived from an application of “Bubbles” (Gosselin & Schyns, 2001), a statistical technique used to assess areas of the pictures that contained potent information to categorization. This analysis found specific areas of the stimuli that mediated task performance at both basic- and superordinate-levels of categorization with different types of stimuli.
This research was supported by National Institute of Mental Health Grant MH47313.