CONCEPT
Knowledge in the World vs. in the Head
Norman's foundational distinction — between knowledge embedded in the environment (available without memorization) and knowledge carried in memory (requiring learning and recall) — and the observation that AI systems place nearly all relevant knowledge in the head.
Norman's knowledge distinction is one of his most practically useful. Knowledge in the world is built into the environment: the stove whose spatial arrangement of knobs maps to its burners puts the mapping in the world, where it is available without memorization. Knowledge in the head must be learned and remembered: the stove whose mapping is arbitrary requires the user to memorize which knob controls which burner. Good design puts as much knowledge as possible in the world, reducing the user's cognitive burden. Chapter 8 of the Norman volume observes that AI systems, by this criterion, are catastrophically badly designed: what the system can do, how to prompt it effectively, when to trust and when to verify, what kinds of errors it is prone to — all of this must be learned by the user through experience, trial and error, or external documentation. None of it is in the world of the interaction.
