ABSTRACT
In 1960 Peter Wason published a short paper reporting a single study investigating people’s inductive reasoning and concept learning with his newly developed ‘2-4-6 task’. Wason’s primary interest in developing this task was to ascertain whether people could discover that a concept is necessary rather than merely sufficient. In this task the experimenter explains to the participant that he has in mind a rule with regard to number triples made up of three integers. The rule is that these integers must be in ascending order of magnitude, but, crucially, the participant doesn’t know what this rule is and therefore has to try to discover it. As a starting point the participant is given an example triple, ‘2-4-6’, which she is told conforms to the rule. The participant is then requested to generate her own triples, with feedback being given in each case as to whether the triple conforms to the experimenter’s rule. In Wason’s (1960) study participants could write down each triple along with their reasons for their choice of numbers and the feedback received. Participants were also reminded that their task was not simply to find numbers that conformed to the rule but to discover the rule itself. Only when they were highly confident that they had discovered the rule were they asked to tell the experimenter what it was. If participants announced an incorrect rule (which was commonplace), they were invited to continue with more testing and could make further announcements. The experiment continued until correct rule announcement or the session reached 45 minutes (or the participants gave up).
