Illusion of Explanatory Depth

Rozenblit and Keil's finding that people believe they understand complex systems and mechanisms FAR more deeply than they actually do—and that this illusion is specific to explanatory knowledge (how things work) rather than factual knowledge (what things are). People rate their understanding of toilets, zippers, and economic policies as high—until asked to actually EXPLAIN the mechanism step by step, at which point their confidence collapses. The illusion persists because we confuse familiarity with understanding: we interact with these systems daily, so we FEEL like we understand them. Explanatory knowledge is the most systematically overestimated type of knowledge.

When to use it

When confident understanding hasn't been tested through step-by-step explanation; when decisions require genuine mechanistic understanding rather than surface familiarity; when team claims of understanding need to be verified; when the quality of understanding matters for prediction and planning.

How it can help

Test your understanding by EXPLAINING, not by rating it. The practice: before claiming to understand something, try to explain the mechanism step by step to someone else (or write it out). The gaps in your understanding will become immediately apparent. For organizations: when teams claim to understand a process, market, or technology, ask them to explain the causal mechanism step by step. The illusion of depth is shattered by the demand for step-by-step explanation. For decision-making: if you can't explain HOW something works, you don't understand it well enough to predict its behavior under new conditions.