Center for the Study of Aging and Human Development & Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA.
Department of Psychology, Yale University, New Haven, CT 06520, USA.
Soc Cogn Affect Neurosci. 2018 May 1;13(5):449-459. doi: 10.1093/scan/nsy021.
Every day, humans make countless decisions that require the integration of information about potential benefits (i.e. rewards) with other decision features (i.e. effort required, probability of an outcome or time delays). Here, we examine the overlap and dissociation of behavioral preferences and neural representations of subjective value in the context of three different decision features (physical effort, probability and time delays) in a healthy adult life span sample. While undergoing functional neuroimaging, participants (N = 75) made incentive compatible choices between a smaller monetary reward with lower physical effort, higher probability, or a shorter time delay versus a larger monetary reward with higher physical effort, lower probability, or a longer time delay. Behavioral preferences were estimated from observed choices, and subjective values were computed using individual hyperbolic discount functions. We found that discount rates were uncorrelated across tasks. Despite this apparent behavioral dissociation between preferences, we found overlapping subjective value-related activity in the medial prefrontal cortex across all three tasks. We found no consistent evidence for age differences in either preferences or the neural representations of subjective value across adulthood. These results suggest that while the tolerance of decision features is behaviorally dissociable, subjective value signals share a common representation across adulthood.
每天，人类都会做出无数需要整合潜在收益（即奖励）信息与其他决策特征（即所需努力、结果概率或时间延迟）的决策。在这里，我们在一个健康成年人的样本中，考察了在三种不同决策特征（体力消耗、概率和时间延迟）的背景下，行为偏好和主观价值的神经表示的重叠和分离。在进行功能神经影像学检查时，参与者（N=75）在较小的金钱奖励与较低的体力消耗、较高的概率或较短的时间延迟与较大的金钱奖励与较高的体力消耗、较低的概率或较长的时间延迟之间做出了激励相容的选择。行为偏好是根据观察到的选择来估计的，主观价值是通过个体双曲线折扣函数来计算的。我们发现，折扣率在不同任务之间没有相关性。尽管在偏好上存在明显的行为分离，但我们发现，在所有三个任务中，内侧前额叶皮层都存在重叠的主观价值相关活动。我们没有发现成年期偏好或主观价值的神经表示在年龄上存在一致差异的证据。这些结果表明，尽管决策特征的容忍度在行为上是可分离的，但主观价值信号在整个成年期都具有共同的表示。
