Everybody Will Win, and All Must Be Hired: Comparing Additivity Neglect with the Nonselective Superiority Bias

Abstract

Two streams of research looking at referent-dependent judgments from slightly different angles are subadditivity research and research on the nonselective superiority bias. Both biases violate basic formal constraints: the probabilities of a set of exclusive events cannot add up to more than 100%, and a set of attractive candidates cannot all be rated as superior to the group mean. We examine in three experiments how these two biases are related, by asking the same participants to perform both kinds of tasks on the same material. Both biases appear to be widespread, even for sets where all alternatives are presented together, but they differ in the way they are affected by response format and experimental setup. Thus, presenting participants with an unbiased set of ratings will reduce but not normalize their probability estimates of the same alternatives; while presenting them with an unbiased (additive) set of probabilities will make most alternatives appear inferior to the group mean, inverting the superiority bias. Self-reports reveal that additivity neglect and the nonselective superiority bias can be based on two main response-strategies: (i) considering each alternative independently or (ii) comparing alternatives, while neglecting their complementarity. In both cases, assessments will be the outcome of a compromise between the perceived "absolute" merits of each alternative, its standing relative to referents, and properties of the response scale.

On the robustness of the brand positivity effect: Is impulsivity a moderator of overly favorable judgments and choices of focal options?

“…Unwarranted favorability toward focal options is not limited to brands narrowly defined, but instead has been observed in myriad judgments and choices in a wide variety of contexts including consumer choice, investing, and managerial judgment and has broad implications for public policy makers, managers, as well as individual consumers (e.g., Posavac et al, 2006Posavac et al, , 2012. Moreover, this bias is widespread, and results either from evaluating one option from a set independently or neglecting the complementary nature of available options (Riege & Teigen, 2017). Research on similar phenomena such as focalism (Wilson et al, 2000;Windschitl et al, 2003), the nonselective superiority bias (Klar, 2002), reference group neglect (Camerer & Lovallo, 1999), subadditivity (Fox & Levav, 2000), and myopia (Fiedler, 2012) is predicated on these processes.…”

The boundary effect: Perceived post hoc accuracy of prediction intervals

“…For instance, verbal phrases are vague in terms of the probabilities they convey (Budescu & Wallsten, 1995), but unequivocal in selectively directing the listener's attention towards the occurrence or non-occurrence of the target event, in other words they are "directional" and can be classified as either positive or negative (Honda & Yamagishi, 2017;Teigen & Brun, 1995). Numeric probabilities are of-ten overestimated (Moore & Healy, 2008;Riege & Teigen, 2017), whereas uncertainty intervals are typically too narrow (Moore, Tenney & Haran, 2016;Teigen & Jørgensen, 2005). Much less is known about how forecasts are evaluated after the actual outcomes have occurred.…”