Fairley Kim, Vyrastekova Jana, Weitzel Utz, Sanfey Alan G
Institute of Tax Law and Economics, Department of Economics, Leiden University, Leiden, Netherlands.
Donders Institute for Brain, Cognition and Behavior, Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, Netherlands.
Front Neurosci. 2019 Jun 26;13:660. doi: 10.3389/fnins.2019.00660. eCollection 2019.
There is overwhelming evidence that the evaluation of both reward decisions and their associated outcomes are closely linked with bilateral activation of the ventral striatum, with these insights stemming from tasks such as the monetary incentive delay task for lotteries and multiround Trust Games for social settings. The essential element in these tasks is an externally provided cue associated with specific gains/trustworthy partners and losses/non-trustworthy partners. However, in reality people typically use their own beliefs to guide their decision-making and assess the likelihood of positive or and negative outcomes. As when participants assess the relationship between cues and rewards, individuals should anticipate rewards in correspondence to their beliefs, i.e., the higher the belief of obtaining a reward in the future, the higher the anticipation of reward. In this study, we use decision-makers' own, naturally occurring, beliefs about both social and non-social contexts to examine the subsequent outcome of their choices. We hypothesize that mechanisms of belief-mediated reward processing are mediated by neural activation in the ventral striatum. An essential feature of our design is the elicitation of individuals' beliefs prior to the decision-making task itself. Furthermore, our incentivized, non-deceptive, decision-making task distinguishes between social - implemented by a Trust Game - and non-social sources, as well as risk and ambiguity as underlying types of uncertainty. Our main result shows that individual beliefs regarding reciprocity likelihoods in both the Trust Game and the lottery influence the amount invested. Subsequently, only the investment amount in the Trust Game parametrically modulates anticipatory reward and outcome evaluation in the ventral striatum. This study demonstrates a first approach at using participants' subjective sets of beliefs to examine reward processing. We discuss its potential promise, outline some limitations, and propose follow-up studies to extend the current approach.
有压倒性的证据表明，奖励决策及其相关结果的评估与腹侧纹状体的双侧激活密切相关，这些见解源于诸如彩票的金钱激励延迟任务和社交环境中的多轮信任游戏等任务。这些任务的关键要素是与特定收益/可信赖伙伴以及损失/不可信赖伙伴相关的外部提供的线索。然而，在现实中，人们通常使用自己的信念来指导决策并评估积极或消极结果的可能性。就像参与者评估线索与奖励之间的关系时一样，个体应该根据自己的信念来预期奖励，即未来获得奖励的信念越高，对奖励的预期就越高。在本研究中，我们使用决策者对社会和非社会环境的自然形成的信念来检验他们选择的后续结果。我们假设信念介导的奖励处理机制是由腹侧纹状体中的神经激活介导的。我们设计的一个重要特征是在决策任务本身之前引出个体的信念。此外，我们的激励性、非欺骗性决策任务区分了社会（通过信任游戏实施）和非社会来源，以及作为潜在不确定性类型的风险和模糊性。我们的主要结果表明，在信任游戏和彩票中关于互惠可能性的个体信念会影响投资金额。随后，只有信任游戏中的投资金额会参数性地调节腹侧纹状体中的预期奖励和结果评估。本研究展示了一种利用参与者主观信念集来检验奖励处理的初步方法。我们讨论了其潜在前景，概述了一些局限性，并提出了后续研究以扩展当前方法。
