Gary Charness

Understanding Social Preferences with Simple Tests

Departures from self-interest in economic experiments have recently inspired models of “social preferences”. We design a range of simple experimental games that test these theories more directly than existing experiments. Our experiments show that subjects are more concerned with increasing social welfare—sacrificing to increase the payoffs for all recipients, especially low-payoff recipients—than with reducing differences in payoffs (as supposed in recent models). Subjects are also motivated by reciprocity: They withdraw willingness to sacrifice to achieve a fair outcome when others are themselves unwilling to sacrifice, and sometimes punish unfair behavior.

Responsibility and Effort in an Experimental Labor Market

Previous indirect evidence suggests that impulses towards pro-social behavior are diminished when an external authority is responsible for an outcome. The responsibility-alleviation effect states that a shift of responsibility to an external authority dampens internal impulses toward honesty, loyalty, or generosity. In a gift-exchange experiment, we find that subjects respond with more generosity (higher effort) when wages are determined by a random process than when assigned by a third party, indicating that even a slight shift in perceived responsibility for the final payoffs can change behavior. Responsibility-alleviation can be a factor in economic environments featuring substantial personal interaction.

Relative payoffs and happiness: an experimental study

Some current utility models presume that people are concerned with their relative standing in a reference group. If this is true, do certain types care more about this than others? Using simple binary decisions and self-reported happiness, we investigate both the prevalence of “difference aversion” and whether happiness levels influence the taste for social comparisons. Our decision tasks distinguish between a person’s desire to achieving the social optimum, equality or advantageous relative standing. Most people appear to disregard relative payoffs, instead typically making choices resulting in higher social payoffs. While we do not find a strong general correlation between happiness and concern for relative payoffs, we do observe that a willingness to lower another person’s payoff below one’s own (competitive preferences) seems correlated with unhappiness.

When Optimal Choices Feel Wrong: A Laboratory Study of Bayesian Updating, Complexity, and Affect

We examine decision-making under risk and uncertainty in a laboratory experiment. The heart of our design examines how one’s propensity to use Bayes’ rule is affected by whether this rule is aligned with reinforcement or clashes with it. In some cases, we create environments where Bayesian updating after a successful outcome should lead a decision-maker to make a change, while no change should be made after observing an unsuccessful outcome. We observe striking patterns: When payoff reinforcement and Bayesian updating are aligned, nearly all people respond as expected. However, when these forces clash, around 50% of all decisions are inconsistent with Bayesian updating. While people tend to make costly initial choices that eliminate complexity in a subsequent decision, we find that complexity alone cannot explain our results. Finally, when a draw provides only information (and no payment), switching errors occur much less frequently, suggesting that the ‘emotional reinforcement’ (affect) induced by payments is a critical factor in deviations from Bayesian updating. There is considerable behavioral heterogeneity; we identify different types in the population and find that people who make ‘switching errors’ are more likely to have cross-period ‘reinforcement’ tendencies.

How Robust is Laboratory Gift Exchange

The gift-exchange game is a form of sequential prisoners dilemma, developed by Fehr et al. (1993), and popularized in a series of papers by Ernst Fehr and co-authors. While the European studies typically feature a high degree of gift exchange, the few U.S. studies provide some conflicting results. We find that the degree of gift exchange is surprisingly sensitive to an apparently innocuous change—whether or not a comprehensive payoff table is provided in the instructions. We also find significant and substantial time trends in responder behavior.

PORTFOLIO CHOICE AND RISK ATTITUDES: AN EXPERIMENT

We study the following basic intuition: when faced with a decision how to split their investment between a risky lottery and an asset with a fixed return, people increase the proportion invested in the risky option the more they like the lottery. We find counter-examples to this, and in fact we find no simple relation between preferences between lotteries and the fraction invested in them. We use three well-documented biases (ambiguity aversion, the illusion of control and myopic loss aversion) to show this. First we replicate the previous results in a laboratory experiment with financial incentives, and then test whether participants are willing to explicitly pay a small sum of money in line with the bias (pay for less ambiguity, more perceived control, or more frequent information about portfolio performance). We then study how portfolio choice depends on these biases. With the parameters chosen, the illusion of control was eliminated when participants were asked to pay to gain more control, and the bias did not affect investment behavior (i.e., participants invested in a risky option the same fraction when faced with more or less control). In the ambiguity treatment, people were willing to pay for less ambiguity, but again the level of ambiguity did not influence investment. Finally, in the myopic loss aversion treatment participants were willing to pay money to have more freedom to choose, even though (in line with the documented bias) they invested less when having more freedom to change their investment.

Does Pay Inequality Affect Worker Effort? Experimental Evidence

We study worker behavior in an efficiency‐wage environment in which coworkers’ wages can influence a worker’s effort. Theoretically, we show that an increase in workers’ responsiveness to coworkers’ wages should lead profit‐maximizing firms to compress wages. Our laboratory experiments, by contrast, show that while workers’ effort choices are highly sensitive to their own wages, effort is not affected by coworkers’ wages. This casts doubt on the notion that workers’ concerns with equity might explain pay policies such as wage compression or wage secrecy.

The Dark Side of Competition for Status

Unethical behavior within organizations is not rare. We investigate experimentally the role of status-seeking behavior in sabotage and cheating activities aiming at improving one’s performance ranking in a flat-wage environment. We find that average effort is higher when individuals are informed about their relative performance. However, ranking feedback also favors disreputable behavior. Some individuals do not hesitate to incur a cost to improve their rank by sabotaging others’ work or by increasing artificially their own performance. Introducing sabotage opportunities has a strong detrimental effect on performance. Therefore, ranking incentives should be used with care. Inducing group identity discourages sabotage among peers but increases in-group rivalry. (This abstract was borrowed from another version of this item.)

Intention and Stochastic Outcomes: An Experimental Study

Do people care about intentions - even when good intentions do not produce good results? In our experiments we find that rates of punishment and reward react strongly to intentions (the wage a firm decides to pay) and more modestly to distributional outcomes (the higher or lower wage actually received including the stochastic component). For example, workers who end up receiving medium wages respond much more positively when this resulted from the firm offering a high wage but bad luck lowered the workers pay than when this resulted from the firm offering a low wage and good luck raised the pay. Copyright 2007 The Author(s). Journal compilation Royal Economic Society 2007.

Cooperation and Competition in Intergenerational Experiments in the Field and the Laboratory

There is economic pressure towards the postponement of the retirement age, but employers are still reluctant to employ older workers. We investigate the comparative behavior of juniors and seniors in experiments conducted both onsite with the employees of two large firms and in a conventional laboratory environment with students and retirees. We show that seniors are no more risk averse than juniors and are typically more cooperative ; both juniors and working seniors respond strongly to competition. The implication is that it may be beneficial to define additional incentives near the end of the career to motivate and retain older workers.