Is the Whole the Sum of its Parts? Neural Computation of Consumer Bundle Valuation in Humans

Humans are often tasked with making decisions about bundles of multiple items and very little is known about how the human brain aggregates, computes, and represents value in such cases. We investigated how the brain evaluates consumer items, both individually and in bundles, and how this activity relates to choice behavior. Human participants (<i>N</i> = 14; 7 female, 7 male) completed a deep-functional MRI protocol while we elicited behavioral valuations for single and bundled items. Behaviorally, we find that bundle values are sub-additively discounted compared to the sum of individual item values. Neurally, we find that the same distributed network in prefrontal cortex computes the value of a bundle and its constituent individual items, but the value representation undergoes a normalization that actively rescales across bundle and single item contexts. These findings suggest that generalized value regions contextually adapt within a valuation hierarchy, as opposed to utilizing an absolute value code.