Unleashing the BEAST: a brief measure of human social information use

Social information enables individuals to reduce uncertainty and increase decision accuracy across a broad range of domains. Intriguingly, individuals and populations consistently differ in social information use. Understanding the underlying causes of this variation has proven challenging due to the lack of a standardized paradigm to quantify social information use. Here we introduce the BEAST (Berlin Estimate AdjuStment Task); a brief (∼5-min), simple, and incentive-compatible behavioural task to quantify individuals' propensities to use social information. In the task, participants observe an image with a number of animals and estimate the total number. Next, they receive another person's estimate, after which they provide a second estimate. An individual's average adjustment quantifies their propensity to use social information. We found that individuals' propensity to use social information is consistent within the task, has considerable test–retest reliability over 9 months, generalizes to other social learning tasks, and correlates with established self-reported measures of social conformity and social proximity. The BEAST thus reliably captures individual variation in social information use. We conclude by highlighting the BEAST's potential to serve as a flexible framework to assess the determinants of human social information use.