Self-serving, altruistic and spiteful lying in the schoolyard

Subjects 5 to 17 years old participate in two rounds of a lying game. In each round, each participant reports one outcome for themselves and one outcome for another random, anonymous person of the same age. We observe frequent but not omnipresent over-reports for oneself (self-serving lying). We also observe small aggregate levels of under-reports for others and a strong positive correlation across rounds in the reports for others, which might be explained by a coexistence of altruistic liars and spiteful liars in our population. Behavior is similar across ages, except for middle schoolers who exhibit a slightly higher inclination towards self-serving and spiteful lying. A focused analysis of choice in middle school reveals some differences by academic performance and socioeconomic status.