Ambiguous Persuasion with Prior Ambiguity

TL;DR

This paper investigates whether ambiguity in communication strategies benefits a sender in persuasion games with prior ambiguity, finding that ambiguity does not provide an advantage in simple binary-state scenarios.

Contribution

It extends Cheng's (2025) no-gain result to environments with prior ambiguity, demonstrating the result holds in binary state and action cases.

Findings

Ambiguity does not benefit the sender in binary state and action persuasion games.

The no-gain result from Cheng (2025) extends to prior ambiguity settings.

Ambiguous communication strategies are not advantageous under MEU preferences.

Abstract

Cheng (2025) establishes that in a persuasion game where both the sender and the receiver have Maxmin Expected Utility (MEU) preferences, the sender never strictly benefits from using ambiguous communication strategies over standard (non-ambiguous) ones. This note extends the analysis to environments with prior ambiguity, i.e., pre-existing ambiguity about the payoff-relevant state, and shows that, in the binary state and binary action case, the same no-gain result continues to hold.