Can Scientists Rationally Assess Conditional Inferences?

Recent studies by Mahoney and Kimper, and by Kern, Mirels and Hinshaw, suggest that scientists do very poorly on a standard psychological task involving inferences about `If... then...' conditionals. More recently, Yachanin found that the nature of the task instructions greatly affected performance on such tasks. In the present study, results obtained from twenty research scientists using Yachanin's modified task are reported. Scientists performed at a very high level, in contrast to non-scientist subjects, displaying understanding of the power of disconfirmatory data in assessing conditionals, and of the possible error of affirming the consequent when only confirmatory data are sought. The results disconfirm the earlier claim that scientists are no more able to use such heuristics than are undergraduates.