Communicating with Anecdotes

TL;DR

The paper develops a Bayesian sender–receiver model where the sender communicates a single anecdote drawn from a panel of signals about an underlying state $ heta$. The sender’s desire to persuade creates a tension between informative signaling and biased reporting, yielding translation-invariant equilibria in which the sender uses targeting schemes with offset $r$ and the receiver debiases by shifting actions, with the key condition $eta(r)-r= ext{Delta}$. Polarization and informational homophily arise as misalignment $ ext{Delta}=M_R-M_S$ grows, and polarization intensifies with the number of anecdotes, especially under non-Gaussian tails; heavy tails can cause a curse of informedness where non-experts become more credible, while commitment can restore welfare by limiting persuasion. The work links to cheap talk, verifiable disclosure, and memory-based interpretations, and it provides precise existence theorems and welfare comparisons across foresight/no-foresight, tail regimes, and commitment scenarios. Overall, it advances understanding of how the feedback between informativeness, bias, and audience structure shapes real-world anecdotes-driven communication.

Abstract

We study a communication game between a sender and a receiver. The sender chooses one of her signals about the state of the world (i.e., anecdotes) and communicates to the receiver who takes an action affecting both players. The sender and the receiver both care about the state of the world but are also influenced by personal preferences, so their ideal actions can differ. We characterize perfect Bayesian equilibria. The sender faces a temptation to persuade: she wants to select a biased anecdote to influence the receiver's action. Anecdotes are still informative to the receiver (who will debias at equilibrium) but the attempt to persuade comes at a cost to precision. This gives rise to informational homophily where the receiver prefers to listen to like-minded senders because they provide higher-precision signals. Communication becomes polarized when the sender is an expert with access to many signals, with the sender choosing extreme outlier anecdotes at equilibrium (unless preferences are perfectly aligned). This polarization dissipates all gains from communication with an increasingly well-informed sender when the anecdote distribution is heavy-tailed. Experts can therefore face a curse of informedness: receivers will prefer to listen to less-informed senders who cannot pick biased signals as easily.

Figures (18)

• Figure 1: Illustration of translation invariant equilibrium
• Figure 2: Timing of communication game
• Figure 3: Examples of translation invariant communication schemes
• Figure 4: Examples of most informative offset $r^*$ under foresight
• Figure 5: $F\sim N(0,1)$

Theorems & Definitions (100)

• Definition 1
• Definition 2
• Definition 3
• Definition 4
• Theorem 2.1
• Theorem 2.2
• Proposition 1
• Proposition 2
• Theorem 3.1
• Lemma 3.1