The influence of expertise in category-based induction

The purpose of the present research is to examine the influence of expertise in confirmation judgment of category-based induction. In experiment 1, doctoral students who were majoring in biology judged confirmation of category-based induction on the illness of birds. Research such as Osherson, Smith, Wilkie, Lopez, & Shafir (1990) has showed that undergraduates with arts backgrounds judged confirmation according to the coverage principle. But doctoral students in biology judged confirmation according to diversity principle, in both general and specific inductions. In experiment 2, in order to find out whether this result was due to expertise in biology, doctoral students majoring in mathematics/physics/psychology judged confirmation of general induction. Even when graduate school students in the same specialty at the same university made judgments, individual differences were seen in the manner of confirmation judgment of category-based induction. Many subjects judged confirmation according to the diversity principle, but subjects who judged according to the coverage principle were seen, too. Therefore, it is likely that the diversity principle in category-based induction was not due to expertise in biology or natural science, but rather was a heuristic strategy of researchers in general. But further research must be done on the belief or knowledge concerning the conclusive factor to determine whether one conforms to the diversity principle or the coverage principle.