Plans and the Structure of Behavior

Plans and the Structure of Behavior was the founding document of what would later be called cognitive psychology's hierarchical turn. Co-authored by George Miller, Eugene Galanter, and Karl Pribram, the book proposed that all human behavior — from reaching for a glass of water to designing a cathedral — is organized by hierarchical structures called TOTE units: Test-Operate-Test-Exit. Before acting, the mind tests the current state of the world against a desired state. If there is a mismatch, it operates — performs some action to reduce the discrepancy. It then tests again. If the mismatch persists, it operates again. If the mismatch is resolved, it exits to the next unit in the hierarchy. A plan is a nested structure of TOTE units, arranged from the most abstract goal to the most concrete action, with each level of the hierarchy decomposing a single goal into sub-goals. The book was dense, technical, wildly ambitious — and, in retrospect, the