How confirmation bias makes persuaders more honest

We study a Bayesian persuasion game in which a decision maker (DM) incurs psychological costs from belief-disconfirming information and chooses whether to engage with the sender’s experiment. We model preference-based confirmation bias as psychological discomfort from exposure to signals that conflict with the DM’s prior beliefs. Whenever persuasion is feasible, the sender must commit to a strictly more informative experiment than in the Kamenica–Gentzkow (2011) benchmark. This increases the DM’s “actual” welfare, defined as material welfare excluding the psychological cost term, when confirmation bias is moderate, while persuasion fails when the bias exceeds a threshold and the DM disengages. We then introduce processing-based confirmation bias, modeled as systematic misperception of signals. In isolation, it does not change equilibrium behavior or the DM’s “actual” welfare, but when combined with preference-based bias it strengthens the disciplining effect for the DM. A dynamic extension shows that future engagement concerns further increase the sender’s incentive to provide informative signals.