Implicit and explicit processing on base rate neglect problems

Base rate reasoning as assessed on Base rate neglect (BRN) Tasks has been studied extensively, with a sizable body of findings indicating that both logical (base rate) and belief-based (case description) processing contribute to responses on the task. Various task conditions have been found to influence which type of processing controls responding. The present study compares two instructional sets, one which requires responding in terms of the base rate information and one which requires responding in accordance with the case description. This manipulation allows for a distinction between explicit processing (set-consistent) and implicit processing (set-inconsistent and potentially interfering). We also manipulated the extremity of the base rates employed in the task and the extremity of the stereotypes contained in the case description. We argue that extremity effects should be present in implicit, but not explicit, processing, suggesting that these effects are the result of limitations in the control of set-inconsistent processing. The results generally supported the predictions. In addition, a proclivity for analytical thinking, as measured by actively open-minded thinking (AOT), was associated with less interference of belief-based processing on logical responding, but greater interference of logical processing on belief-based responding.