Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, UK.
Department of Experimental Psychology, University of Oxford, South Parks Road, Oxford OX1 3UD, UK.
Neuron. 2017 Feb 8;93(3):705-714.e4. doi: 10.1016/j.neuron.2016.12.038.
Humans and other animals accumulate resources, or wealth, by making successive risky decisions. If and how risk attitudes vary with wealth remains an open question. Here humans accumulated reward by accepting or rejecting successive monetary gambles within arbitrarily defined temporal contexts. Risk preferences changed substantially toward risk aversion as reward accumulated within a context, and blood oxygen level dependent (BOLD) signals in the ventromedial prefrontal cortex (PFC) tracked the latent growth of cumulative economic outcomes. Risky behavior was captured by a computational model in which reward prompts an adaptive update to the function that links utilities to choices. These findings can be understood if humans have evolved economic decision policies that fail to maximize overall expected value but reduce variance in cumulative outcomes, thereby ensuring that resources remain above a critical survival threshold.
人类和其他动物通过连续做出有风险的决策来积累资源或财富。风险态度如何随财富变化仍然是一个悬而未决的问题。在这里，人类通过在任意定义的时间背景下接受或拒绝连续的货币赌博来积累奖励。随着奖励在一个背景下的积累，风险偏好会朝着风险规避发生显著变化，并且腹内侧前额叶皮层（PFC）中的血氧水平依赖（BOLD）信号会跟踪累积经济结果的潜在增长。风险行为可以通过一个计算模型来捕捉，该模型认为奖励促使对将效用与选择联系起来的函数进行自适应更新。如果人类已经进化出经济决策策略，这些发现是可以理解的，这些策略不能使总体预期价值最大化，但可以减少累积结果的方差，从而确保资源保持在关键生存阈值之上。
