Research

Experiments are used to examine the effects of social comparisons in ultimatum bargaining. We inform responders about the average offer before they decide whether to accept or reject their specific offer. This significantly increases offers and offer-specific rejection probabilities. For comparison, we consider another change in informational conditions: telling responders the total pie is \$30—ex ante it was either \$15 or \$30—affects offers and rejection probabilities roughly as much. Our results are consistent with people’s dislike for deviations from the norm of equity but inconsistent with fairness theories, where people dislike income disparity between themselves and their referents.

Using experiments, we examine whether the decision to trust a stranger in a one-shot interaction is equivalent to taking a risky bet, or if a trust decision entails an additional risk premium to balance the costs of trust betrayal. We compare a binary-choice Trust game with a structurally identical, binary-choice Risky Dictator game with good or bad outcomes. We elicit individuals' minimum acceptable probabilities (MAPs) of getting the good outcome such that they would prefer the chance to the sure payoff. First movers state higher {MAPs} in the Trust game than in situations where nature determines the outcome.

Most contracts, whether between voters and politicians or between house owners and contractors, are incomplete. "More law", it typically is assumed, increases the likelihood of contract performance by increasing the probability of enforcement and/or the cost of breach. This paper studies a contractual relationship where the first mover has to decide whether she wants to enter a contract without knowing whether the second mover will perform. We analyze how contract enforceability affects individual performance for exogenous preferences. Then we apply a dynamic model of preference adaptation and find that economic incentives have a non-monotonic impact on behavior. Individuals perform a contract when enforcement is strong or weak but not with medium enforcement probabilities. Trustworthiness is "crowded in" with weak and "crowded out" with medium enforcement. In a laboratory experiment we test our model's implications and find support for the crowding prediction. Our finding is in line with the recent work on the role of contract enforcement and trust in formerly Communist countries.

Communication increases contributions to public goods. Our experimental results indicate that communication is not always required. Silent identification suffices to raise solidarity in prisoner's dilemma and dictator games. Increases in solidarity are not only due to expectations of reciprocity. While mutual identification induces individuals to converge to the social norm, the spread of the distribution of choices increases with one-way identification and with communication. As others are no longer faceless entities, one-way identification decreases social distance, inducing interaction-specific solutions. Communication allows more information to be transferred and, therefore, more scope for abandoning the norms.

The price system is generally thought to be the epitome of efficiency. In some cases, however, lotteries are preferred to the market as a social decision-making system for reasons of fairness. As recent research has shown, neither procedure is always well accepted among the general population. We analyze the social acceptability of both mechanisms and apply our framework to the allocation of social burdens, namely the siting of nuclear waste facilities. Lotteries are only acceptable if they are applied to a set of efficient options. The market is accepted if the production of fairness precedes the use of prices.