People had little trouble generating new hypotheses about the rule, sometimes quite complex ones. But what they hardly ever did was to test their hypotheses by offering triplets that did not conform to their hypothesis. For example, proposing 2–4–5 (yes) and 2–4–3 (no) would have helped people zero in on the actual rule: any series of ascending numbers. Wason called this phenomenon the confirmation bias, the tendency to seek out and interpret new evidence in ways that confirm what you already think. People are quite good at challenging statements made by other people, but if it’s your belief,
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