In two experiments, people repeatedly judged individual options with respect to both overall value and attribute values. When required to choose between two snacks, each differing in two attributes (pleasure and nutrition), people’s assessments of value shifted from pre- to post-choice in the direction that spread the alternatives further apart so as to favor the winner, thereby increasing confidence in the choice. This shift was observed not only for ratings of overall value, but also for each of the two individual attributes. The magnitude of the coherence shift increased with choice difficulty as measured by the difference in initial ratings of overall value for the two options, as well as with a measure of attribute disparity (the degree to which individual attributes "disagree" with one another as to which option is superior). In Experiment 2, a task requiring comparison of value similarity generated the same qualitative pattern of value and confidence changes, even though the similarity judgments entirely preceded the actual choice task. These findings support the hypothesis that active comparison of values is the core component of the decision process during which perceived values are shifted so as to more sharply distinguish the items being compared.
bioRxiv Subject Collection: Neuroscience