Children's judgements of gambles: a disordinal violation of utility

Violations of utility are often attributed to people's differential reactions to risk versus certainty or uncertainty, or more generally to the way that people perceive outcomes and consequences. However, a core feature of utility is additivity, and violations may also occur because of averaging effects. Averaging is pervasive in intuitive riskless judgement throughout many domains, as shown with Anderson's Information Integration approach. The present study extends these findings to judgement under risk. Five- to 10-year old children showed a disordinal violation of utility because they averaged the part worths of duplex gambles rather than add them, as adults do, and as normatively prescribed. Thus adults realized that two prizes are better than one, but children preferred a high chance to win one prize to the same gamble plus an additional small chance to win a second prize. This result suggests that an additive operator may not be a natural component of the intuitive psychological concept of expected value that emerges in childhood. The implications of a developmental perspective for the study of judgement and decision are discussed.