S. Nageeb Ali

Waiting to Settle: Multilateral Bargaining with Subjective Biases

We study multilateral bargaining games where agents disagree over their bargaining power. We show that if agents are extremely optimistic, there may be costly delays in an arbitrarily long finite game but if optimism is moderate, all sufficiently long games end in immediate agreement. We show that the game with extreme optimism is highly unstable in the finite-horizon, and we examine the ramifications of this instability on the infinite-horizon problem. Finally, we consider other voting rules, and show that the majority-rule may be more efficient than the unanimity rule when agents are optimistic.

A Theory of Momentum in Sequential Voting

This paper develops a rational theory of momentum in elections with sequential voting. We analyze a two-candidate election in which some voters are uncertain about the realization of a state variable that can affect their preferences between the candidates. Voters receive private signals about the state and vote in an exogenously fixed sequence, observing the history of votes at each point. We show that there is a strict equilibrium with Posterior-Based Voting: each voter votes for the candidate she believes to be better at the time of casting her vote, taking into account the information revealed in prior votes. In this equilibrium, herding can occur on a candidate with positive probability, and occurs with probability approaching one in large voting games. Our results help understand and have implications for sequential voting mechanisms such as presidential primaries and roll-call voting.

Recognition for sale

I examine the consequences of letting players compete for bargaining power in a multilateral bargaining game. In each period, the right to propose an offer is sold to the highest bidder, and all players pay their bids. If players vote according to any rule in which no player has veto power, then the first proposer captures the entire surplus. If a full consensus is needed for an offer to be accepted, then the first proposer shares the surplus with at most one other player, and as the period length between offers vanishes, one player may capture virtually the entire surplus. In settings with a stochastic or an endogenous surplus, players are unwilling to efficiently delay agreement or invest in the surplus.

Herding with costly information

This paper incorporates costly information into a model of observational learning. Individuals would like to avoid the cost of buying information and free-ride on the public history. The paper characterizes when learning is nevertheless complete. Necessary and sufficient conditions for complete learning follow from an elementary principle: a player purchases information only if it can influence her action. With a “coarse” action space, learning is complete if and only if for every cost c>0, a positive measure of types can acquire, at cost less than c, an experiment that can overturn the public history. With a “rich” action space, learning is complete if and only if for every cost c>0, a positive measure of types can acquire any informative signal at cost weakly less than c. The results are applied to financial markets to evaluate when markets are informationally efficient despite information being costly.