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 and methods of assessing attention 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, like humans, pigeons attend more to relevant than to irrelevant stimulus features during category learning. Nonetheless, unlike humans, post-acquisition assessment reveals that pigeons less selectively attend to deterministic than to probabilistic features of category members, indicating that pigeons' attention is more distributed. Fresh opportunities now exist for more effectively understanding the evolution and mechanisms of categorical cognition.