Wason’s 1960 paper explores how individuals test hypotheses using a simple card-based logic task and consistently fail to adopt a falsification strategy, instead favoring confirmatory evidence. The research provided one of the earliest empirical demonstrations of confirmation bias, showing that participants often select evidence that aligns with their assumptions rather than seeking disconfirming information. This cognitive tendency was framed within the psychology of reasoning and has had enduring influence on how we understand human logic, judgment, and scientific thinking. The study laid important groundwork for future explorations of heuristics, cognitive limitations, and decision-making processes.
From University of Florida, Quarterly Journal of Experimental Psychology, and Internet Archive