Testing Interval Independence Versus Configural Weighting Using Judgments of Strength of Preference

Judges made choices and raced strengths of preference between gambles composed of 50-50 chances to receive either of 2 monetary outcomes (x, y). Others judged how much they would pay to play their chosen gamble rather than the other gamble. Judged strengths of preference violated interval independence, because they depended on the value of a common outcome. For example, judges offered to pay an average of $44 to play ($74, $100) instead of ($8, $100) but offered to pay only $24 to play ($6, $74) instead of ($6, $8). Results violated the theory that utility of gambles is a nonconfigural average of the values of the outcomes and that strengths of preference are monotonically related to utility differences. Results can be explained by a configural weight model in which the lowest outcome receives greater weight.