Evaluation mode is an important yet under-studied aspect of decision-making. All decisions are made in one of two evaluation modes or some mix of the two. One is joint evaluation (JE), in which different options are presented together and evaluated simultaneously. The other is single evaluation (SE), in which different options are presented separately, and each option is evaluated in isolation.
This article reviews existing literature on how JE and SE can lead to reversed preferences, with one option favored in JE and another option favored in SE, in domains including hiring, consumer choice, moral judgments and healthcare decisions. For example, in JE, a plain-looking but experienced job candidate would be favored over a good-looking but less-experienced job candidate, but in SE, the good-looking but less experienced candidate would be favored. We also review existing research on the “less is better” phenomenon-that in SE (but not in JE), a normatively less valuable option is judged more favorably than its more valuable alternative. For example, in SE (but not in JE), 7 oz. of ice cream served in a 5-oz. cup is valued more favorably than 8 oz. of ice cream served in a 10-oz. cup.
To interpret JE/SE preference reversals and the less-is-better effect, several explanations have been proposed, such as a want/should conflict, a within-category versus between-category comparison, the option as information model, and the dual-process model. The present review focuses on the general evaluability theory (GET), which ascribes JE/SE preference reversals and the less-is-better effect to attribute evaluability. According to GET, the evaluability of an attribute depends conjunctively on three factors: evaluation mode (JE versus SE), knowledge of the decision-maker about the attribute, and the inherent/learned nature of the attribute. Not only can GET explain JE/SE preference reversals and the less-is-better effect, it also explains many other effects, such as scope neglect, differences in risk preference between JE and SE, differences in time preference between JE and SE, misprediction of future hedonic experiences, and so on.
Understanding JE-SE differences and attribute evaluability also offers insight into how to improve decisions in contexts such as fundraising, pricing strategy, public service, and subjective well-being. |||The review suggests that evaluation mode (JE versus SE) is an important independent variable that influences a wide range of decisions in counterintuitive ways and thereby provides opportunities to design choice-architecture-based nudges to improve decisions. Yet despite its importance, evaluation mode has not been well-studied and therefore is a fertile ground for researchers to explore and develop.