Are All Dictator Game Results Artifacts?

You walk into a laboratory, and you read a set of instructions that tell you that your task is to decide how much of a $10 pie you want to give to an anonymous other person who signed up for the experimental session.

This describes, more or less, the Dictator Game, a staple of behavioral economics with a history dating back more than a quarter of a century. The Dictator Game (DG) might not be the drosophila melanogaster of behavioral economics – the Prisoner’s Dilemma can lay plausible claim to that prized analogy – but it could reasonably aspire to an only slightly more modest title, perhaps the e. coli of the discipline. Since the original work, more than 20,000 observations in the DG have been reported.

The first thing to be careful to mark about the DG is that running such a game does not, of course, in itself, constitute an experiment. The Dictator Game, in isolation, is better understood as a measuring tool. It measures, in some sense, generosity. If you like to think that people have “(pro-)social preferences,” – that people are happy when others are happy (as I am) – then measuring how much money a person gives to another individual in the carefully controlled setting of the DG is one way to assess the strength of this preference.

The DG can be, and has been, used as a control condition. So, for instance, early work used the DG as a control condition for the Ultimatum Game (UG), which is like the Dictator Game except that the first player’s proposed split can be rejected by the second player, in which case both get nothing. Comparing the DG and UG, so the logic went, allows the experimenter to measure how much more people propose in the UG because of the fear of the offer being rejected as opposed to, loosely, simply being generous. The DG, in this sense, controls for pro-social preferences as an explanation in the UG.

All but one implementation of the Dictator Game, as far as I know, until recently, have had something potentially important in common: the people playing the game know that they were in an experiment. This circumstance, of course, is very difficult to avoid, and obviously this claim can be made of the vast array of methods used across the experimental social science literature. To be sure, conducting experiments on subjects without them being aware of the fact that they are in an experiment is difficult, not to mention potentially unethical. Still, some of us have wondered for some time if there is something special about this fact when it comes to the Dictator Game. After all, we each are in Dictator Games every time we walk into the world with money in our pockets. We could, if we wished, split the cash we’re carrying with a stranger in the street. My casual observation of my own behavior suggests that if my pro-social preferences were measured this way, I would come across as stingy indeed or, as economists would have it, “rational.”

Further, there is something pragmatically odd about the “game.” (Even Wittgenstein might have balked at calling the Dictator Game a “game,” and he famously cast the net for this term broadly indeed.) Subjects in this experiment are faced with one decision, one lever to press, or not press, as it were. Subjects who give nothing are in the peculiar position of coming to a lab, reading instructions, and then, roughly, doing nothing at all and collecting their loot. It’s easy to imagine that subjects think there’s all something funny about this, and feel some urge to push on the single lever the experimenter has given them to play with, if only a little bit.

This raises the question: How much would participants in a Dictator Game give to the other person if they did not know they were in a Dictator Game study? Simply following me around during the day and recording how much cash I dispense won’t answer this question because in the DG, the money is provided by the experimenter. So, to build a parallel design, the method used must move money to subjects as a windfall so that we can observe how much of this “house money” they choose to give away.

And that is what Winking and Mizer did in a paper now in press and available online (paywall) in Evolution and Human Behavior, using participants, fittingly enough, in Las Vegas. Here’s what they did. Two confederates were needed. The first, destined to become the “recipient,” was occupied on a phone call near a bus stop in Vegas. The second confederate approached lone individuals at the bus stop, indicated that they were late for a ride to the airport, and asked the subject if they wanted the $20 in casino chips still in the confederate’s possession, scamming people into, rather than out of money, in sharp contradiction of the deep traditions of Las Vegas. The question was how many chips the fortunate subject transferred to the nearby confederate.

Figure 1 from Winking & Mizer, in press.

Figure 1 from Winking & Mizer, in press.

And the authors didn’t choose Las Vegas because they thought it would be a nice place to take a few trips to conduct field research. You couldn’t run the experiment easily just anywhere, with dollars, because the cover story wouldn’t work – dollars travel too well. The nice thing about Vegas is that casino chips might plausibly be given away in this fashion because the chips have value only in Vegas. (Probably a dedicated person could figure out a way to exchange the chips for cash through eBay or some such – or save them for a subsequent visit – but giving away forgotten chips when one is leaving Vegas is plausible enough.)

In a second condition, the confederate with the chips added a comment to the effect that the subject could “split it with that guy however you want,” indicating the first confederate. This condition brings the study a bit closer, but not much closer, to lab conditions, In a third condition, subjects were asked if they wanted to participate in a study, and then did so along the lines of the usual DG, making the treatment considerably closer to traditional lab-based conditions.

The difference between the first two treatments and the third treatments is interesting, but, as I said at the beginning, the DG should be thought of as a measuring tool. Figure 1 shows how many chips people give away in the DG in the three treatments. In conditions 1 and 2, the number of people (out of 60) who gave at least one chip to the second confederate was… zero. To the extent you think that this method answers the question, how much Dictator Game giving is due to people knowing they’re in an experiment, the answer is, “all of it.”

Of course this is one study one population and it would be hasty to made too much out of it. Still, if the results of this study in the West is telling us what people think they should do when they find themselves in a study on altruism, then it could be that the cross-cultural data using the DG are telling us what people across cultures think they should do when they find themselves in a study on altruism.


Winking, J., & Mizer, N. (in press). Natural-field dictator game shows no altruistic giving. Evolution and Human Behavior

22. May 2013 by kurzbanepblog
Categories: Blog | 28 comments

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