People preferentially seek confirming evidence and avoid testing their own hypotheses.
Evidence
The results were shocking. Out of twenty-nine very intelligent subjects, only six of them proposed the correct rule without any previous incorrect guesses. Thirteen proposed one incorrect rule and nine proposed two or more incorrect rules. One subject was unable to propose any rule at all. What happened? As Wason reports, the subjects who failed at the task seemed unwilling to propose any set of numbers that tested the accuracy of their hypothesized rule and instead proposed only those that would confirm it. … Rather than use their chance to see whether their intuitive rule of “increase by intervals of two” was incorrect, they continued to propose only confirming instances. When these subjects announced their rule they were shocked to learn that it was incorrect, even though they had never tested it with any disconfirming instances. — Lee McIntyre, Post-Truth, 93
Categorization
- DEFINE: Concrete experimental demonstration of confirmation bias, showing the mechanism rather than just the concept.
- XREF: The 2-4-6 task parallels later work on hypothesis testing and falsification like Klayman and Ha. — connects to: People often resist or reverse belief updating rather than tracking evidence — Sander van der Linden, Foolproof: Why Misinformation Infects…, 104; People deploy selective perception and motivated reasoning routinely when faced with evidence — Sander van der Linden, Foolproof: Why Misinformation Infects…, 144; Directionally motivated reasoning makes people reject disconfirming evidence and seek explanations for it. — Sander van der Linden, Foolproof: Why Misinformation Infects…, 166 (+13 more)
- SEED: The 2-4-6 task is a vivid pedagogical demonstration of why disconfirmation is hard — usable in any essay on how to test beliefs.
Broader Connections
- Lay theorists avoid seeking disconfirming evidence rather than falsifying hypotheses
#corroborates(0.95) - Confirmation-seeking bias appears across many domains, not just artificial laboratory tasks.
#expands(0.88) — Diego Gambetta, Trust - Making and Breaking Cooperative…, 634 - Even disconfirmation evidence often fails to break a person’s confirmation bias
#expands(0.86) — Lee McIntyre, Post-Truth, 94 - People unconsciously avoid confronting evidence that contradicts their sense of safety
#corroborates(0.85) — Julien Gracq, Balcony in the Forest, 229 - People resist updating beliefs even at the cost of accuracy
#expands(0.82) - Selective evidence use lets people maintain the illusion of being objective while holding prejudice
#expands(0.80) — , Rudman, Laurie A - On the Nature of…, 2095 - People often distort evidence to fit preexisting worldviews rather than updating beliefs
#expands(0.80) — Sander van der Linden, Foolproof, 108 - Disconfirming evidence can strengthen rather than weaken committed beliefs.
#complicates(0.75) — Philip Mirowski, Never Let a Serious Crisis Go to Waste, 97 - Gruesome evidence can backfire because people avoid thinking about it
#qualifies(0.72) — Bob Altemeyer, The Authoritarian Specter, 3221 - Non-Christians may resist evidence contradicting their beliefs
#exemplifies(0.72) — Bob Altemeyer, The Authoritarian Specter, 4168