Tasks That Prime Deliberative Processes Boost Base Rate Use

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

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 informatio

Adults Are Sensitive to Variance When Making Likelihood Judgments

People have shown sensitivity to variance in studies in which variance has been provided separately from other statistical information, but not in other studies in which variance must be derived from raw data. However, such studies typically test people’s sensitivity to variance via probability judgments: participants are asked to make judgments based on how confident they are that sample means are representative of a population. In this study, we instead investigate whether people are able to use variability when making likelihood judgments: participants determined from which of two possible populations a sample was more likely to have been drawn. Choices were influenced by variance, even when controlling for sample size, base rate, and the absolute difference between sample means and population µs

Prompting deliberation increases base-rate use

People often base judgments on stereotypes, even when contradictory base-rate information is provided. In a sample of 438 students from two state universities, we tested several hypotheses regarding why people would prefer stereotype information over base-rates when making judgments: A) People believe stereotype information is more diagnostic than base-rate information, B) people find stereotype information more salient than base-rate information, or C) even though people have some intuitive access to base-rate information, they may need to engage in deliberation before they can make full use of it, and often fail to do so. In line with the deliberative failure account, and counter to the diagnosticity account, we found that inducing deliberation by having people evaluate statements supporting the use of base-rates increased the use of base-rate information. Moreover, counter to the salience and diagnosticity accounts, asking people to evaluate statements supporting the use of stereotypes decreased reliance on stereotype information. Additionally, more numerate subjects were more likely to make use of base-rate information