Assessing Attention in Category Learning by Animals

Appreciating that varied stimuli belong to different categories requires that attention be differentially allocated to relevant and irrelevant features of those stimuli. Such selective attention ought to be definable and measurable in both humans and nonhuman animals. We first discuss the definition of attention and methods of assessing it in animals. We then introduce new experimental and computational tools for assessing attention in pigeons both during and after category learning. Deploying these tools, we have found that, as do humans, pigeons attend more to relevant than to irrelevant stimulus features during category learning. Nonetheless, postacquisition assessment reveals that, compared with human adults, pigeons less selectively attend to deterministic features in preference to probabilistic features of category members, which indicates that pigeons' attention is more distributed. Fresh opportunities now exist for more effectively understanding the evolution and mechanisms of categorical cognition.