Testing vs. Believing Hypotheses: Magical Ideation in the Judgement of Contingencies.

This paper examines the idea that an important dimension of human cognition is the amount of objective evidence required for perception of meaningful patterns. At the clinical extreme of this dimension are patients with hallucinations and delusions who experience perception with no external evidence and see connections between objectively unrelated events. Also, normal individuals exhibit considerable variation along this continuum. The theory proposed here predicts that normal subjects with low evidential criteria will be more likely to accept causal explanations, not only for everyday ''paranormal'' coincidences, but also for random contingencies in a laboratory experiment. This prediction was confirmed when 40 students completed a differential reinforcement of low rates (DRL) task designed to induce superstitious behaviour and were then questioned about their hypotheses concerning the contingencies for successful performance. Participants scoring high on the Magical Ideation scale (indicating greater belief in paranormal phenomena) tested fewer hypotheses during the task, and they ended up believing in more hypotheses regarding illusory contingencies than did their low-scoring peers. We proposed that a continuum of hypothesis-testing behaviour underlies the schizotypy continuum, with ''positive'' schizotypal traits reflecting a Type I error bias and ''negative'' traits a Type II error bias. Differential activation patterns within frontal-limbic networks are tentatively suggested as a physiological correlate of the behavioural continuum.