Categorization is "Baked" Into the Brain

Categorization, the grouping of similar objects, actions, or events, is fundamental to adaptive behavior. Traditionally, neuroscience assumes it begins with feature detection following to, as a final stage, assigning representations stored in memory. We review converging evidence from neuroanatomy, electrophysiology, brain imaging and cognitive science to suggest a different view: Categorization is not the end stage of perception but occurs throughout signal processing, from the very beginning. It is a core computational strategy of the brain, implemented through predictive feedback signals that organize feedforward processing. Implications for theory, future research, and neuropsychiatric disorders are discussed.