Do decisions shape preference? Evidence from blind choice.

Psychologists have long asserted that making a choice changes a person's preferences. Recently, critics of this view have argued that choosing simply reveals preexisting preferences, and that all studies claiming that choice shapes preferences suffer from a fundamental methodological flaw. Here we address this question directly by dissociating preexisting preferences from decision making. We studied participants who rated different vacation destinations both before and after making a blind choice that could not be guided by preexisting preferences. As an additional control, we elicited ratings in a condition in which a computer made the decision for the participants. We found that preferences were altered after participants made a blind choice, but not after a computer dictated the decision. The results suggest that just as preferences form choices, choices shape preferences.