One decision, thought through once

Koriat, Lichtenstein & Fischhoff (1980), Reasons for confidence, Journal of Experimental Psychology: Human Learning and Memory 6(2), 107–118: when participants listed reasons that contradicted the answer they had chosen, their confidence became better calibrated to how often they were actually right. Listing supporting reasons gave no such improvement. The studies concerned general-knowledge questions, not personal life decisions, so the session builds on the principle and has not been tested itself. The thought experiment of a failure in hindsight is a common decision method without its own effect study here.