Testing four explanations for the better/worse-than-average effect: Single- and multi-item entities as comparison targets and referents

In six experiments, we tested four explanations for the better/worse-than-average effect (B/WTA) by manipulating the number of items comprising the target or referent of direct comparison. A single-item target tended to be rated more extremely than a single-item or a multi-item referent (Experiments 1-3). No B/WTA was obtained, however, when a multi-item target was compared with either a single- or multi-item referent (Experiments 4 and 5). A bias favoring a multi-item target was found only if cohesiveness among the items was increased through instructions (Experiment 6). The Unique-Attributes Hypothesis generally provided the best explanation the findings; the focalism explanation also demonstrated some empirical viability. The results suggest that important preferential decision-making outcomes can be affected by both the number of items and whether items are strategically manipulated to serve as targets or referents of comparison.