Support for a Deliberative Failure Account of Base-Rate Neglect: Prompting Deliberation Increases Base-Rate Use

People often base judgments on stereotypes, even when contradictory base-rate information is provided. It has been suggested this occurs because people fail to engage or complete deliberative reasoning needed to process numerical base-rate information, and instead rely on intuitive reasoning. However, recent research indicates people have some access to this base-rate information even when they make stereotype judgments. Here we tested several hypotheses regarding these phenomena: A) People may believe stereotype information is more diagnostic; B) People may find stereotype information more salient; C) People have some intuitive access to baserate information, but must engage in deliberation to make full use of it. Aligning with account C, and counter to account A, we found inducing deliberation generally increased the use of base-rate information. Counter to account B, inducing deliberation about stereotype information decreased use of stereotype information. Additionally, more numerate participants were more likely to make use of base-rate information.