Modes of persuasion toward unanimous consent

Abstract

A fully committed sender seeks to sway a collective adoption decision through designing experiments. Voters have correlated payoff states and heterogeneous thresholds of doubt. We characterize the sender-optimal policy under unanimity rule for two persuasion modes. Under general persuasion, evidence presented to each voter depends on all voters' states. The sender makes the most demanding voters indifferent between decisions, while the more lenient voters strictly benefit from persuasion. Under individual persuasion, evidence presented to each voter depends only on her state. The sender designates a subgroup of rubber-stampers, another of fully informed voters, and a third of partially informed voters. The most demanding voters are strategically accorded high-quality information. A tremendous share of decision-making in economic and political realms is made within collective schemes. We explore a setting in which a sender seeks to get the unanimous approval of a group for a project he promotes. Group members care about different aspects of the project and might disagree on whether the project should be implemented. They might also vary in the loss they incur if the project is of low quality in their respective aspects. The sender designs experiments to persuade the members to approve. When deciding as part of a group, individuals understand the informational and payoff interdependencies among their decisions. Previous literature has focused mostly on the aggregation and acquisition of (costly) information from exogenous sources in collective decision-making. In contrast, our focus is on optimal persuasion of a heterogeneous group by a biased sender who is able to