Opitz Bertram, Ferdinand Nicola K, Mecklinger Axel
Experimental Neuropsychology Unit, Saarland University Saarbrücken, Germany.
Front Hum Neurosci. 2011 Feb 1;5:8. doi: 10.3389/fnhum.2011.00008. eCollection 2011.
In the present experiment, we used event-related potentials (ERP) to investigate the role of immediate and delayed feedback in an artificial grammar learning (AGL) task. Two groups of participants were engaged in classifying non-word strings according to an underlying rule system, not known to the participants. Visual feedback was provided after each classification either immediately or with a short delay of 1 s. Both groups were able to learn the artificial grammar system as indicated by an increase in classification performance. However, the gain in performance was significantly larger for the group receiving immediate feedback as compared to the group receiving delayed feedback. Learning was accompanied by an increase in P300 activity in the ERP for delayed as compared to immediate feedback. Irrespective of feedback delay, both groups exhibited learning related decreases in the feedback-related positivity (FRP) elicited by positive feedback only. The feedback-related negativity (FRN), however, remained constant over the course of learning. These results suggest, first, that delayed feedback is less effective for AGL as task requirements are very demanding, and second, that the FRP elicited by positive prediction errors decreases with learning while the FRN to negative prediction errors is elicited in an all-or-none fashion by negative feedback throughout the entire experiment.
在本实验中，我们使用事件相关电位（ERP）来研究即时反馈和延迟反馈在人工语法学习（AGL）任务中的作用。两组参与者根据一个他们不知道的潜在规则系统对非单词字符串进行分类。每次分类后，立即或延迟1秒提供视觉反馈。两组都能够学习人工语法系统，分类表现的提高表明了这一点。然而，与接受延迟反馈的组相比，接受即时反馈的组在表现上的提升显著更大。与即时反馈相比，学习过程中延迟反馈的ERP中P300活动增加。无论反馈延迟如何，两组仅在由正反馈引发的反馈相关正波（FRP）方面都表现出与学习相关的下降。然而，反馈相关负波（FRN）在学习过程中保持不变。这些结果表明，首先，由于任务要求非常苛刻，延迟反馈对AGL的效果较差；其次，由正预测误差引发的FRP随着学习而降低，而在整个实验中，由负反馈以全或无的方式引发对负预测误差的FRN。
