Nilanjan Roy

How cheap talk enhances efficiency in threshold public goods games

This paper uses a Bayesian mechanism design approach to investigate the effects of communication in a threshold public goods game. Individuals have private information about contribution costs. Individuals can each make a discrete contribution. If the number of contributors is at least equal to the threshold, a public benefit accrues to all members of the group. We experimentally implement three different communication structures prior to the decision move: (a) simultaneous exchange of binary messages, (b) larger finite numerical message space and (c) unrestricted text chat. We obtain theoretical bounds on the efficiency gains that are obtainable under these different communication structures. In an experiment with three person groups and a threshold of two, we observe significant efficiency gains only with the richest of these communication structures, where participants engage in unrestricted text chatting. In that case, the efficiency bounds implied by mechanism design theory are achieved.

It's Your Turn: Experiments with Three-Player Public Good Games

We report results from experiments designed to investigate the prevalence of turn-taking in three-person finitely repeated threshold public good games without communication. Individuals can each make a discrete contribution. If the number of contributors is at least equal to the threshold, a public benefit accrues to all group members. Players take turns to provide the public good each round when the endowments are homogeneous. When the turn-taking path is at odds with efficiency or under private information of endowments, players seldom engage in taking turns. An endogenous-move protocol limits the frequency of mis-coordinated outcomes every round.

Price Dynamics and Consumption Smoothing in Experimental Asset Markets

We report the results of an experiment designed to study the determinants of asset price movement and consumption smoothing behavior across asset markets populated with varying proportion of traders with and without having induced motive to smooth consumption. Although the asset is over-priced compared to the risk-neutral fundamental value in all sessions, the extent of over-pricing and magnitude of price movement is significantly higher when traders with no induced motive to trade are present. We also find that the price of the asset co-moves with the dividend state, with price predictability being higher in the presence of traders with induced motive to smooth consumption. Participants motivated to minimize consumption fluctuations are able to do so with the inclination being more for those having lower initial endowment. With fixed prices, traders are able to smooth consumption not only over periods but also over the dividend states.