Heuristic bias in children's reasoning in the personal domain

Human reasoning is often biased by heuristic thinking, but the nature of heuristic bias is yet to be exactly explained. As the focus of most relevant experiments on heuristic bias in reasoning has been exclusively on adults, we conducted a study with children aged between 7 and 16 years (N = 129). Our aim was to identify which element in the reasoning process fails and thus underlies the heuristic bias in children’s reasoning in the personal domain. We explored the probability of judging violation among this group of children in reasoning tasks involving personal domain rules and by measuring their lexical decision times. The results showed that the heuristic bias in children’s reasoning in the personal domain was caused by monitoring failure among those who were of junior school age and by inhibition failure among those who were of middle school age. As most of the children of senior school age were able to complete the inhibition process, they had less heuristic bias.