Cross Logan, Webb Ryan, O'Doherty John P
Stanford University.
University of Toronto.
bioRxiv. 2025 May 1:2025.04.28.650827. doi: 10.1101/2025.04.28.650827.
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 human brain evaluates consumer items, both individually and in bundles, and how this activity relates to choice behavior. Participants underwent a deep-fMRI scanning 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 pre-frontal cortex computes the value of a bundle and its constituent individual items, but the value representation undergoes a normalization that actively re-scales 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.
人类常常面临对多个物品组合进行决策的任务，而对于在这种情况下人类大脑如何聚合、计算和表征价值却知之甚少。我们研究了人类大脑如何评估消费品，包括单个物品和物品组合，以及这种活动与选择行为之间的关系。在我们引出对单个和组合物品的行为估值时，参与者接受了深度功能磁共振成像扫描方案。在行为上，我们发现与单个物品价值的总和相比，组合物品的价值被次相加性地折扣了。在神经层面，我们发现前额叶皮层中相同的分布式网络计算组合物品及其组成单个物品的价值，但价值表征会经历一种归一化过程，该过程会在组合物品和单个物品的情境中积极地重新缩放。这些发现表明，广义价值区域在估值层次结构中会根据上下文进行调整，而不是使用绝对值编码。
