Edward L. Thorndike

American psychologist (1874–1949), a founder of educational psychology and comparative (animal) learning research, whose puzzle-box experiments produced the law of effect — behavior followed by a satisfying consequence is "stamped in" — and whose 1920 paper "A Constant Error in Psychological Ratings" coined the term halo effect. He matters to this vault as the origin, a century upstream, of a mechanism the vault's modern source-evaluation cluster rediscovered without naming: the bleed of a global impression into ratings meant to be independent.

Thorndike's law of effect is also a recognized ancestor of reinforcement learning's credit-assignment problem, tying him to the vault's AI-history threads as well as its epistemics ones.

References

• claim-thorndike-1920-halo-effect-ratings-too-high-and-too-even
• observation-halo-effect-names-the-2025-reliability-credibility-leak
• entity-halo-effect
• Capture: 10-inbox/raw/2026-08-03-hop-thorndike-halo-effect.md