The temporal dynamics of base rate neglect: People may not be intuitive statisticians after all


According to a classic view of reasoning, intuition is fast and effortless but fallible, while reflection is slow and effortful, but reliable. Biases, therefore, emerge when a reasoner’s intuitions are systematically wrong and they fail to recognise the need to reflect on them. Recent evidence, however, suggests that people are to some degree aware when their intuitions are wrong, leading to slower responses, and reduced confidence. A possible explanation for this is that our intuitions actually cue multiple conflicting responses, including the correct one, but the wrong one dictates our behaviour unless we consciously detect and resolve this conflict. Here, we tested this explanation using base rate neglect problems, commonly used to assess conflict in reasoning, and recording participants’ mouse cursor movements as they chose between possible answers to the problems under time pressure. Descriptions affected both participants’ early mouse movements and ultimate responses, and interfered with their use of the base rates, while base rates rarely interfered with participants’ use of descriptions, and when they did their influence was at a later point in time. Thus, despite suggestive findings elsewhere, our results support the classic of view reasoning about these problems.

Proceedings of the Cognitive Science Society