Test understanding by generating three examples from different domains — vocabulary is not comprehension
Before claiming to understand a complex topic, generate at least three concrete examples from different domains that instantiate the concept, and if you cannot produce varied examples, treat this as evidence that you have acquired vocabulary without understanding.
Why This Is a Rule
Vocabulary acquisition masquerades as understanding. You read about "cognitive load" and can use the term in sentences — but can you generate three concrete examples from different domains that instantiate the concept? Software engineering (too many state variables in a function exceed working memory), cooking (following a complex recipe while managing multiple timers and temperatures), and driving (navigating an unfamiliar city while talking on the phone). If you can produce varied, non-obvious examples, you understand the concept's structure, not just its label.
The three-domain requirement is the critical test. One example could be the textbook example you memorized. Two could both come from your primary domain. Three from different domains proves you've grasped the underlying structure that the examples share — which is understanding, not vocabulary.
Rozenblit and Keil's "illusion of explanatory depth" research (2002) showed that people consistently overestimate their understanding of concepts they can name. The multi-domain example test is the fastest way to puncture this illusion and reveal the actual depth of understanding.
When This Fires
- Before teaching, presenting, or explaining a concept to others
- After reading about a new concept and wanting to verify genuine understanding
- When someone asks "do you understand X?" and you're about to say yes
- During any learning process where you want a quick comprehension check
Common Failure Mode
Generating three examples from the same domain: three software engineering examples of cognitive load. Same-domain examples test familiarity, not understanding. The concept must transfer across domains — that's what understanding means. If you can't produce examples outside your primary domain, you know how the concept applies in your field but don't grasp its general structure.
The Protocol
When you believe you understand a concept: (1) Generate three concrete examples from three different domains (e.g., engineering, relationships, cooking — whatever domains you know). (2) For each example, verify: does it genuinely instantiate the concept's core mechanism, not just share surface vocabulary? (3) If you produce three varied examples → understanding is genuine. Proceed with confidence. (4) If you stall at one or two → you have vocabulary without understanding. Study the concept's structure further before claiming comprehension.