The evaluability hypothesis: An explanation for preference reversals between joint and separate evaluations of alternatives

This research investigates a particular type of preference reversal (PR), existing between joint evaluation, where two stimulus options are evaluated side by side simultaneously, and separate evaluation, where these options are evaluated separately. I first examine how this PR differs from other types of PRs and review studies demonstrating this PR. I then propose an explanation, called the evaluability hypothesis, and report experiments that tested this hypothesis. According to this hypothesis, PRs between joint and separate evaluations occur because one of the attributes involved in the options is hard to evaluate independently and another attri bute is relatively easy to evaluate independently. I conclude by discussing prescriptive implications of this research. (C) 1996 Academic Press, Inc.