Monkeys Quickly Learn and Generalize Visual Categories without Lateral Prefrontal Cortex

SummaryCategorization is a basic mental process that helps individuals distinguish among groups of negative and positive objects, e.g., poisons and nutrients, or predators and prey. Monkey experiments have suggested that lateral prefrontal cortex (LPFC) participates in learning and processing visual categories. However, in humans category specific visual agnosia follows inferior temporal cortex but not LPFC damage. Here, we use a new behavioral approach to show that both normal monkeys and those with bilateral removal of LPFC learn and generalize perceptual categories of related visual stimuli rapidly without explicit instruction. These results strongly indicate that visual categorization occurs at some earlier stage of feed-forward processing, presumably in temporal cortex, without top-down information from LPFC.

► Monkeys learned to categorize cats and dogs in a day without explicit instruction
► Bilateral LPFC ablations did not affect new visual categorization learning
► Monkeys with LPFC ablations learn to generalize visual categorization