The most socially-informative discrimination ever discovered.
Kling on the topic (from 2007).
ADDED: ‘Don’t! The secret of self-control’, by Jonah Lehrer in The New Yorker (2009):
Starting in 1981, Mischel sent out a questionnaire to all the reachable parents, teachers, and academic advisers of the six hundred and fifty-three subjects who had participated in the marshmallow task, who were by then in high school. He asked about every trait he could think of, from their capacity to plan and think ahead to their ability to “cope well with problems” and get along with their peers. He also requested their S.A.T. scores.
Once Mischel began analyzing the results, he noticed that low delayers, the children who rang the bell quickly, seemed more likely to have behavioral problems, both in school and at home. They got lower S.A.T. scores. They struggled in stressful situations, often had trouble paying attention, and found it difficult to maintain friendships. The child who could wait fifteen minutes had an S.A.T. score that was, on average, two hundred and ten points higher than that of the kid who could wait only thirty seconds.