The Reconstruction of Choice Value in the Brain: A Look into the Size of Consideration Sets and Their Affective Consequences Hye-young Kim, Yeonsoon Shin, and Sanghoon Han Abstract ■ It has been proposed that choice utility exhibits an inverted U-shape as a function of the number of options in the choice set. However, most researchers have so far only focused on the “physically extant” number of options in the set while disregard- ing the more important psychological factor, the “subjective” number of options worth considering to choose—that is, the size of the consideration set. To explore this previously ignored aspect, we examined how variations in the size of a consider- ation set can produce different affective consequences after making choices and investigated the underlying neural mecha- nism using fMRI. After rating their preferences for art posters, participants made a choice from a presented set and then re- ported on their level of satisfaction with their choice and the level of difficulty experienced in choosing it. Our behavioral results demonstrated that enlarged assortment set can lead to greater choice satisfaction only when increases in both consid- eration set size and preference contrast are involved. Moreover, choice difficulty is determined based on the size of an individ- ualʼs consideration set rather than on the size of the assortment set, and it decreases linearly as a function of the level of contrast among alternatives. The neuroimaging analysis of choice-making revealed that subjective consideration set size was encoded in the striatum, the dACC, and the insula. In addition, the striatum also represented variations in choice satisfaction resulting from alterations in the size of consideration sets, whereas a common neural specificity for choice difficulty and consideration set size was shown in the dACC. These results have theoretical and prac- tical importance in that it is one of the first studies investigating the influence of the psychological attributes of choice sets on the value-based decision-making process. ■ INTRODUCTION We face a great number of choices in our daily lives. In the contemporary world, there are a stunning number of options, sometimes seeming almost infinite, to choose from in any single area; for example, from selecting vaca- tion destinations to opting for particular insurance plans. Although classical economics and psychology had consen- sus that higher number of choice options is always better (Zuckerman, Porac, Lathin, Smith, & Deci, 1978; Langer & Rodin, 1976), recent empirical findings suggest a counter- view: Having many options may not always leave indi- viduals better off (Scheibehenne, Greifeneder, & Todd, 2010; Schwartz, 2004; Iyengar & Lepper, 2000). This ad- verse phenomenon has been shown in multiple ways, including decreases in choice satisfaction, choice motiva- tion, and consumption rates in field study (Chernev, 2003a, 2003b; Iyengar & Lepper, 2000). On the basis of these previous studies, it has been proposed that positive affect arising from choice (i.e., choice satisfaction) draws an inverted U-shaped function as the number of alterna- tives increases because “benefits satiate and costs escalate” concomitantly with an increase in set size (Reutskaja & Hogarth, 2009; Coombs & Avrunin, 1977). This is primarily because an excessive number of alternatives produces cog- nitive overload resulted from excessive information search- ing cost and consequently increases choice difficulty. In this article, we label this phenomenon the “set size effect.” Taking a closer look at the set size effect, we can note that there are three components that are affected by any change in the size of an assortment set, and in effect, each of them might stimulate a positive change in affect: (1) set size: the physically extant number of options that one can choose from, (2) consideration set size: the psy- chologically perceived number of options that one would consider choosing from, (3) contrast: the relative distinc- tiveness of the chosen option compared with the other unchosen alternatives. Generally, enlarging the size of the assortment set leads to an increase in the size of the consideration set, but this is not always true (Scheibehenne et al., 2010; Hauser & Wernerfelt, 1990). For instance, if a larger set accompanies a larger consideration set, the con- trast would expand only by a little, if at all. On the other hand, if there are no additional options attractive enough to be included in oneʼs decision pool, the size of the con- sideration set will remain the same, but the contrast will be magnified to a greater extent. As explained above, these subfactors of the set size can alter and consequently affect Yonsei University, Seoul, Korea © 2014 Massachusetts Institute of Technology Journal of Cognitive Neuroscience 26:4, pp. 810–824 doi:10.1162/jocn_a_00507