结构知识错误而非奖励敏感性不足解释了衰老过程中的元控制减弱

Structural knowledge error,rather than reward insensitivity,explains the reduced metacontrol in aging

人们根据成本-效益权衡原则灵活地调整无模型(习惯性)和基于模型(目标导向)策略的权重,这种能力被称为元控制。最近的研究表明:老年人的元控制灵活性减弱。然而,老年人的元控制缺陷究竟源于认知因素还是动机因素仍然存在争议。本研究结合瞳孔测量记录和具有不同任务结构及奖励水平的序列决策任务对这一问题进行了研究。研究结果复现了之前的研究发现,即老年人采用了更少的基于模型策略,并且在奖励水平改变时元控制灵活性不足。然而,瞳孔分析表明了老年人对奖励水平的敏感性。口头报告分析揭示了老年人的任务结构知识存在个体差异,结构知识较好的亚组与年轻人表现出相似的模式。计算仿真证明结构知识不准确会妨碍元控制。以上结果表明,老年人元控制的灵活性不足并非由于缺乏动机,而是结构知识不准确。

Humans flexibly adjust their reliance on model-free(habitual)and model-based(goal-directed)strategies according to cost‒benefit trade-offs,the ability of which is known as metacontrol.Recent studies have suggested that older adults show reduced flexibility in metacontrol.However,whether the metacontrol deficit in aging is due to cognitive or motivational factors remains ambiguous.The present study investigated this issue using pupillometry recording and a sequential decision-making task with varied task structures and reward stakes.Our results revealed that older adults performed less model-based control and less flexibility when the reward stake level changed,consistent with previous studies.However,pupillometry analysis indicated that older adults showed comparable sensitivity to the reward stake.Older adults varied in task structure knowledge according to their oral reports,and the subgroup with good structural knowledge exerted a similar pattern to younger adults.Computational simulation verified that poor structure knowledge representation impaired metacontrol.These results suggest that the inflexible metacontrol in the elderly population might not be due to motivational factors but rather poor structure knowledge.