Own and others' confidence in social information use.

The behavior of friends, colleagues, television hosts, and social media feeds affects what we buy, how we dress, and who we vote for. The confidence with which those opinions are expressed shapes how much weight individuals give them. Yet little is known about how one's own confidence and others' confidence jointly determine social information use. We present results of two incentivized decision-making tasks (N = 203 and N = 213, samples from the U.S.A.) where participants could adjust their initial judgments upon observing judgments of peers and their confidence. Adjustments were most sensitive to the confidence of others when participants' own confidence was low. Confidence also affected heuristic strategies: confident others prompted participants to compromise and copy social information more often, rather than to stick with their initial estimates. We discuss how following confident others when uncertain can improve decision-making, but also leaves people vulnerable to sources of misinformation.