Seminar

How much do people (additionally) believe a news story because it’s been shared by a friend? How much should they believe it for that reason, if at all? To answer these questions I conduct a series of lab & field experiments in India with ~800 pairs of real-life friends. I collect information on how individuals (sharers) decide which stories to share, and how their friends (receivers) update their beliefs in response. I find receivers over-interpret sharing as a sign of a story’s veracity and the sharer’s faith in it, while discounting other reasons/motivations for sharing. As a result, receivers’ trust in shared stories increases irrespective of the sharers’ belief in them, with false stories accruing greater additional trust. To understand why, I measure how the same receivers update if they (i) could observe the sharer’s _beliefs_ about these stories instead of sharing decisions; and (ii) observe computer-generated signals of fixed accuracy instead of subjective signals from their friend. I find several mechanisms contribute to receivers’ biased inference: receivers overestimate how well sharers’ beliefs predict a story’s veracity; miscalculate the relevance of sharers’ beliefs to sharing decisions; and exhibit base-rate neglect, updating the most on stories they least trusted originally.