Key Laboratory of Behavioral Science, Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.
PLoS One. 2012;7(7):e41048. doi: 10.1371/journal.pone.0041048. Epub 2012 Jul 17.
How people make decisions under risk remains an as-yet-unresolved but fundamental question. Mainstream theories about risky decision making assume that the core processes involved in reaching a risky decision include weighting each payoff or reward magnitude by its probability and then summing the outcomes. However, recently developed theories question whether payoffs are necessarily weighted by probability when making a risky choice. Using functional connectivity analysis, we aimed to provide neural evidence to answer whether this key assumption of computing expectations holds when making a risky choice. We contrasted a trade-off instruction choice that required participants to integrate probability and payoff information with a preferential choice that did not. Based on the functional connectivity patterns between regions in which activity was detected during both of the decision-making tasks, we classified the regions into two networks. One network includes primarily the left and right lateral prefrontal cortices and posterior parietal cortices, which were found to be related to probability in previous reports, and the other network is composed of the bilateral basal ganglia, which have been implicated in payoff. We also found that connectivity between the payoff network and some regions in the probability network (including the left lateral prefrontal cortices and bilateral inferior parietal lobes) were stronger during the trade-off instruction choice task than during the preferential choice task. This indicates that the functional integration between the probability and payoff networks during preferential choice was not as strong as the integration during trade-off instruction choice. Our results provide neural evidence that the weighting process uniformly predicted by the mainstream theory is unnecessary during preferential choice. Thus, our functional integration findings can provide a new direction for the investigation of the principles of risky decision making.
人们如何在风险下做出决策仍然是一个尚未解决但至关重要的问题。关于风险决策的主流理论假设，涉及做出风险决策的核心过程包括根据概率对每个收益或奖励幅度进行加权，然后对结果进行求和。然而，最近发展的理论质疑在做出风险选择时是否必然根据概率对收益进行加权。使用功能连接分析，我们旨在提供神经证据来回答在做出风险选择时，计算期望的这个关键假设是否成立。我们对比了需要参与者整合概率和收益信息的权衡指令选择与不需要的偏好选择。基于在这两个决策任务期间检测到活动的区域之间的功能连接模式，我们将区域分类为两个网络。一个网络主要包括左右外侧前额皮质和后顶叶皮质，这些区域在之前的报告中与概率有关，另一个网络由双侧基底节组成，这些区域与收益有关。我们还发现，在权衡指令选择任务期间，收益网络与概率网络中的一些区域（包括左侧前额皮质和双侧下顶叶）之间的连接比在偏好选择任务期间更强。这表明，在偏好选择期间，概率和收益网络之间的功能整合不如权衡指令选择期间的整合强。我们的结果提供了神经证据，表明主流理论统一预测的加权过程在偏好选择期间是不必要的。因此，我们的功能整合发现可以为风险决策原则的研究提供新的方向。
