Violation of utility theory in unique and repeated gambles.

This article is concerned with a recent debate on the generality of utility theory. It has been argued by Lopes (1981) that decisions regarding preferences between gambles are different for unique and repeated gambles. The present article provides empirical support for the need to distinguish between these two. It is proposed that violations of utility theory obtained under unique conditions (e.g., Kahneman & Tversky, 1979), cannot necessarily be generalized to repeated conditions.