We investigate the determinants of giving in a lab-in-the-field experiment with large stakes. Study participants in urban Mozambique play dictator games where their counterpart is the closest person to them outside their household. When given the option, dictators do a large fraction of giving...

The "Hawthorne effect," a concept familiar to all students of social science, has had a profound influence both on the direction and design of research over the past 75 years. The Hawthorne effect is named after a landmark set of studies conducted at the Hawthorne plant in the 1920s. The first...

Several recent laboratory experiments have shown that the use of explicit incentives--such as conditional rewards and punishment--entail considerable "hidden" costs. The costs are hidden in the sense that they escape our attention if our reasoning is based on the assumption that people are...

An important dialogue between theorists and experimentalists over the past few decades has raised the study of the interaction of psychological and economic incentives from academic curiosity to a bona fide academic field. One recent area of study within this genre that has sparked interest and...

We present evidence from a natural field experiment involving nearly 100,000 individuals on the effects of offering economic incentives for blood donations. Subjects who were offered economic rewards to donate blood were more likely to donate, and more so the higher the value of the rewards....

Recent discoveries in behavioral economics have led to important new insights concerning what can happen in markets. Such gains in knowledge have come primarily via laboratory experiments--a missing piece of the puzzle in many cases is parallel evidence drawn from naturally-occurring field...

Using a high-stakes field experiment conducted with a financial brokerage, we implement a novel design to separately identify two channels of social influence in financial decisions, both widely studied theoretically. When someone purchases an asset, his peers may also want to purchase it, both...

In many low- and middle-income countries blood donations per capita are substantially lower than in advanced economies. In these countries blood supply is mostly collected through donations by relatives and friends of individuals needing transfusions or to replace blood used in emergencies. The...

Policymakers are increasingly using norm-based messages to influence individual decision-making. We partner with a metropolitan water utility to implement a natural field experiment examining the effect of such messages on residential water demand. The data, drawn from more than 100,000...

Recent evidence suggests that the default options implicit in economic choices (e.g., 401(k) savings by white-collar workers) have extraordinarily large effects on decision-making. This study presents a field experiment that evaluates the effect of defaults on savings among a highly...