Preference reversals: Violations of unidimensional procedure invariance.
Peep F. M. Stalmeier, Peter P. Wakker, Thom G. G. Bezembinder · Journal of Experimental Psychology Human Perception & Performance · 1997
Preference reversals have usually been explained by weighted additive models, in which different tasks give rise to different importance weights for the stimulus attributes, resulting in contradictory trade-offs.This article presents a preference reversal of a more extreme nature.Let (10, 5 Migr) denote living 10 years with a migraine for 5 days per week.Many participants preferred (10, 5 Migr) to (20, 5 Migr).However, when asked to equate these two options with a shorter period of good health, they usually demanded more healthy life years for (20, 5 Migr) than for (10, 5 Migr).This preference reversal within a single dimension cannot be explained by different importance weights and suggests irrationalities at a more fundamental level.Most participants did not change their responses after being confronted with their inconsistencies.One of the most frustrating findings in the classical view of preferences is the preference reversal phenomenon, originally discovered by Lichtenstein & Slovic (1971) and Lindman (1971) and subsequently confirmed (see Slovic and Lichtenstein, 1983, for a review).In an example of the basic phenomenon, ($x, yY) denotes a delayed payment in which one receives $x in y years from now.Many people, when asked to choose between the delayed payments ($1,600, 1.5Y) and ($3,550, 10Y), prefer the first.However, when people are asked to state the instantaneous monetary value of these delayed payments, the majority assign a higher value to the second one (Tversky, Slovic, & Kahneman, 1990).Even when confronted with these seemingly contradictory actions, some people do not change their choices or evaluations but prefer to adhere to them and accept these paradoxical actions (Lichtenstein & Slovic, 1971).Several explanations have been offered for these findings.At first, preference reversals were mostly explained as violations of transitivity.