The Black Swan: The Impact of the Highly Improbable · chapter 3 · id the-black-swan-c3-06-confirmation-bias-leads-people

“Confirmation bias leads people to seek information that supports their existing beliefs while ignoring contradictory evidence. Wason's 2-4-6 task (1960) demonstrated that subjects overwhelmingly test confirming rather than disconfirming examples.”

holdsconfidence: high⚠ extracted by pipeline, re-audit pending

Receipts

Wason (1960), 'On the Failure to Eliminate Hypotheses in a Conceptual Task', QJEPpaywalled — manual check queued
In the 2-4-6 task, subjects were asked to discover a rule governing number triples. The vast majority tested only confirming instances (e.g., 8-10-12 if they hypothesized 'increasing by 2') rather than attempting to falsify their hypothesis.
Copernican Revolution: Confirmation Bias and Wason's Tasksource alive
Confirmation bias occurs in everyday reasoning and scientific contexts. In Wason's experiment, subjects failed to test alternative hypotheses even when explicitly encouraged to find counterexamples.
Explorable: Confirmation Bias and the Wason Rule Discovery Testsource alive
The actual rule was simply 'any ascending sequence,' but subjects who hypothesized more specific rules (like 'consecutive even numbers') overwhelmingly tested only confirmatory triples, often announcing their wrong rule with high confidence.

This claim is a stable, citable object. If you can falsify a verdict, tell us — corrections are loud here.