Obrecht and Chesney (2016) contend that deliberation supports greater base rate use. In line with this, they found that prompting deliberation by evaluating arguments about the usefulness of base rate and/or stereotype data increased subsequent use of base rates in judgment tasks. However, an alternative account of these results is that the intervention increased base rate use merely by increasing the salience of base rate information, rather than by increasing deliberation. Here we examine these accounts in two experiments. Experiment 1 showed that participants prompted to deliberate by evaluating arguments used base rates more in subsequent judgements, compared to participants who were merely reminded of relevant information. Experiment 2 showed that participants prompted to deliberate by completing math problems prior to the judgment task also increased their base rate use. Taken together, these results support the theory that tasks that prompt deliberative processes increase normative use of base rates.

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