Wellcome Trust Centre for Neuroimaging, University College London, London, United Kingdom ; Centre for Functional MRI of the Brain (FMRIB), University of Oxford, Oxford, United Kingdom.
PLoS Comput Biol. 2013;9(9):e1003225. doi: 10.1371/journal.pcbi.1003225. Epub 2013 Sep 12.
A central question in cognitive neuroscience regards the means by which options are compared and decisions are resolved during value-guided choice. It is clear that several component processes are needed; these include identifying options, a value-based comparison, and implementation of actions to execute the decision. What is less clear is the temporal precedence and functional organisation of these component processes in the brain. Competing models of decision making have proposed that value comparison may occur in the space of alternative actions, or in the space of abstract goods. We hypothesized that the signals observed might in fact depend upon the framing of the decision. We recorded magnetoencephalographic data from humans performing value-guided choices in which two closely related trial types were interleaved. In the first trial type, each option was revealed separately, potentially causing subjects to estimate each action's value as it was revealed and perform comparison in action-space. In the second trial type, both options were presented simultaneously, potentially leading to comparison in abstract goods-space prior to commitment to a specific action. Distinct activity patterns (in distinct brain regions) on the two trial types demonstrated that the observed frame of reference used for decision making indeed differed, despite the information presented being formally identical, between the two trial types. This provides a potential reconciliation of conflicting accounts of value-guided choice.
认知神经科学中的一个核心问题是，在价值导向的选择中，选项是如何被比较以及决策是如何被做出的。很明显，需要几个组成过程；这些过程包括识别选项、基于价值的比较，以及执行决策的行动。不太清楚的是这些组成过程在大脑中的时间优先顺序和功能组织。有竞争关系的决策模型提出，价值比较可能发生在替代行动的空间中，或者在抽象商品的空间中。我们假设，观察到的信号实际上可能取决于决策的框架。我们从执行价值导向选择的人类中记录了脑磁图数据，其中两种密切相关的试验类型被交错进行。在第一种试验类型中，每个选项都单独显示，这可能导致受试者在每个动作被揭示时估计每个动作的价值，并在动作空间中进行比较。在第二种试验类型中，两个选项同时呈现，这可能导致在承诺采取特定行动之前在抽象商品空间中进行比较。两种试验类型上明显的活动模式（在不同的大脑区域）表明，尽管两种试验类型中呈现的信息在形式上是相同的，但用于决策的观察参考系确实不同。这为价值导向选择的相互冲突的解释提供了一种潜在的调和。
