DISTINCT INFORMATION SEARCH AND VALUE COMPUTATION IN WITHIN- AND ACROSS-DOMAIN CHOICES

Decisions can be made within domains, where options share similar attributes, and across domains, where options differ fundamentally. Current theories of value-based decisions, particularly the common-currency theory, posit that the brain translates the various attributes of different options into a common value, enabling a standardized value-comparison mechanism. We challenge this assumption by proposing that the need to compute integrated values depends on the type of decisions. First, we assume that overt information gathering relies on distinct search strategies in within- compared to across-domain decisions (specifically, the frequency of attribute-wise comparisons is higher in the former). Furthermore, we hypothesize that integrated values in the value-dependent area (ventromedial prefrontal cortex (vmPFC)) are represented differently in within- and across-domain choices. To test this hypothesis, we developed a value-based, multi-attribute decision-making task that included both types of choices. N = 50 healthy participants were instructed to complete the task while their fMRI signals and gaze data were recorded. As predicted, participants showed more attribute-wise searches (Figure 1A) in within-domain choices and more option-wise searches in across-domain choices (Figure 1B). However, overall behavioral performance did not differ between decision types (Figure 1C). We demonstrated that vmPFC reflects the subjective value difference between options only in within-domain choices and to a significantly higher extent than across-domain choices (Figure 1D). Together, these findings suggest that people employ distinct search and choice strategies depending on the decision type, and that an integrated subjective value representation of each option may not be necessary for all types of decisions.