Zou Amy R, Muñoz Lopez Daniela E, Johnson Sheri L, Collins Anne G E
Department of Psychology, University of California, Berkeley, Berkeley, CA, United States.
Institute of Human Development, University of California, Berkeley, Berkeley, CA, United States.
Front Psychiatry. 2022 Mar 14;13:800290. doi: 10.3389/fpsyt.2022.800290. eCollection 2022.
Impulsivity is defined as a trait-like tendency to engage in rash actions that are poorly thought out or expressed in an untimely manner. Previous research has found that impulsivity relates to deficits in decision making, in particular when it necessitates executive control or reward outcomes. Reinforcement learning (RL) relies on the ability to integrate reward or punishment outcomes to make good decisions, and has recently been shown to often recruit executive function; as such, it is unsurprising that impulsivity has been studied in the context of RL. However, how impulsivity relates to the mechanisms of RL remains unclear. We aimed to investigate the relationship between impulsivity and learning in a reward-driven learning task with probabilistic feedback and reversal known to recruit executive function. Based on prior literature in clinical populations, we predicted that higher impulsivity would be associated with poorer performance on the task, driven by more frequent switching following unrewarded outcomes. Our results did not support this prediction, but more advanced, trial-history dependent analyses revealed specific effects of impulsivity on switching behavior following consecutive unrewarded trials. Computational modeling captured group-level behavior, but not impulsivity results. Our results support previous findings highlighting the importance of sensitivity to negative outcomes in understanding how impulsivity relates to learning, but indicate that this may stem from more complex strategies than usually considered in computational models of learning. This should be an important target for future research.
冲动性被定义为一种类似特质的倾向，即倾向于做出未经充分思考或时机不当的鲁莽行为。先前的研究发现，冲动性与决策缺陷有关，尤其是在需要执行控制或奖励结果的情况下。强化学习（RL）依赖于整合奖励或惩罚结果以做出明智决策的能力，并且最近已被证明经常需要执行功能；因此，在强化学习的背景下研究冲动性也就不足为奇了。然而，冲动性与强化学习机制之间的关系仍不清楚。我们旨在研究在一个具有概率反馈和反转的奖励驱动学习任务中冲动性与学习之间的关系，已知该任务需要执行功能。基于临床人群的先前文献，我们预测较高的冲动性将与任务表现较差相关，这是由无奖励结果后更频繁的转换所驱动的。我们的结果不支持这一预测，但更先进的、依赖试验历史的分析揭示了冲动性对连续无奖励试验后的转换行为的特定影响。计算模型捕捉到了组水平的行为，但没有捕捉到冲动性结果。我们的结果支持先前的研究发现，强调了对负面结果的敏感性在理解冲动性与学习之间关系中的重要性，但表明这可能源于比学习计算模型中通常考虑的更为复杂的策略。这应该是未来研究的一个重要目标。
