Title: On Categories, Pictures, and the Goals of Comparative Psychology.
Abstract: The ability to categorize objects and events has long been an object of an intense interest and rigorous research in both humans and nonhuman animals (see Lazareva & Wasserman, 2008; Mareschal, Quinn, & Lea, 2010, for reviews). Until the seminal Herrnstein and Loveland’s study (1964), most of the comparative research used simple and well-defined stimuli (e.g., 1000-Hz tone or a 450 nm light) as discriminanda. Although easily controllable, such stimuli have little relationship to the tasks faced by animals in their natural environments: After all, discriminating a hawk from a conspecific is unlikely to be based on the difference in a single wavelength or pure tone.