If you've earned it, you deserve it: ultimatums, with Lego

Abstract The ultimatum and dictator games were developed to help identify the fundamental motivators of human behavior, typically by asking participants to share windfall endowments with other persons. In the ultimatum game, a common observation is that proposers offer, and responders refuse to accept, a much larger share of the endowment than is predicted by rational choice theory. However, in the real world, windfalls are rare: money is usually earned. I report here a small study aimed at testing how participants react to an ultimatum game after they have earned their endowments by either building a Lego model or spending some time sorting out screws by their length. I find that the shares that proposers offer and responders accept are significantly lower than that typically observed with windfall money, an observation that is intensified when the task undertaken to earn the endowment is generally less enjoyable and thus perhaps more effortful (i.e., screw sorting compared to Lego building). I suggest, therefore, that considerations of effort-based desert are often important drivers behind individual decision-making, and that laboratory experiments, if intended to inform public policy design and implementation, ought to mirror the broad characteristics of the realities that people face.