Is the story of the Fourth Cookie true?

Question

This story of a psychology experiment was told as part of a Commencement Address by author Michael Lewis. It has been quoted in a number of places around the web.

They began by grabbing students, as lab rats. Then they broke the students into teams, segregated by sex. Three men, or three women, per team. Then they put these teams of three into a room, and arbitrarily assigned one of the three to act as leader. Then they gave them some complicated moral problem to solve: say what should be done about academic cheating, or how to regulate drinking on campus.

Exactly 30 minutes into the problem-solving the researchers interrupted each group. They entered the room bearing a plate of cookies. Four cookies. The team consisted of three people, but there were these four cookies. Every team member obviously got one cookie, but that left a fourth cookie, just sitting there. It should have been awkward. But it wasn’t. With incredible consistency the person arbitrarily appointed leader of the group grabbed the fourth cookie, and ate it. Not only ate it, but ate it with gusto: lips smacking, mouth open, drool at the corners of their mouths. In the end all that was left of the extra cookie were crumbs on the leader’s shirt.

Is this account of the experiment accurate?

Answer 1

An experiment like the one described happened. How accurate that depiction is of what actually happened is unknown, as no paper was ever published covering the study and now the details are lost to faulty memory. Without the details, we cannot assess the quality of the experiment either.

The best explanation I found is The Cookie-Monster Study: The highly influential memory of a long-lost study. To summarize:

• The first source to mention the experiment (a review paper) was "Power, approach, and inhibition" by Keltner et al. (2003). It cited an unpublished manuscript by Ward and Keltner (1998).
• Ward had all the details of the experiment, but Keltner lost contact with him (apparently in 1996).
• Keltner has said there were 4 cookies sometimes when asked, and 5 at other points.
• A graphic in Keltner et al. (2003) on how many cookies low power and high power men and women each ate shows that high power men ate fewer cookies than low power men. However, this contradicts what Keltner says happened and it even contradicts the description of what happened in the 2003 paper (apparently not being noticed in review).
• The website mentions Legitimacy Crisis? Behavioral Approach and Inhibition When Power Differences are Left Unexplained as another experiment along the same lines as the original experiment, but I couldn't find a way to read it (for free) to verify that. (The set up was not exactly the same.)