Explicit and Implicit Contributions to Learning in a Sensorimotor Adaptation Task
Explicit and Implicit Contributions to Learning in a Sensorimotor Adaptation Task
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DOI：
10.1523/jneurosci.3619-13.2014
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发表时间：
2014-02-19
影响因子：
5.3
通讯作者：
Ivry, Richard B.
中科院分区：
文献类型：
--
作者：
Taylor, Jordan A.;Krakauer, John W.;Ivry, Richard B.
视觉自适应被认为是一个隐含的过程，其结果是当使用感官预测误差信号来更新前向模型时。人类能力的一个显著特征是接受口头指令和采用策略解决任务的能力;这种外显过程可以在视觉适应过程中使用。在这里，我们使用了一种新颖的任务设计，使我们能够获得连续的口头报告的目标方向，而参与者学习了视觉旋转。我们有两个主要假设：外显学习的贡献会受到指令的调节，内隐学习的贡献会受到错误反馈的调节。通过直接测定目标方向，我们可以识别外显成分的时间过程，并通过减法，分离出内隐成分的学习。外显和内隐对学习贡献的时间进程存在显著差异。由目标误差驱动的外显学习是通过最初对偏向正确解的目标方向进行较大然后较小的探索来实现的。相比之下，内隐学习，由感官预测错误驱动，是缓慢和单调的。连续错误反馈降低了外显学习的幅度，增加了内隐学习的贡献。指令的存在稍微增加了初始学习的速度，只对内隐学习产生了微妙的影响。我们的结论是，视觉适应，即使在没有指令的情况下，从目标错误驱动的外显学习和预测错误驱动的前向模型的内隐学习之间的相互作用的结果。
Visuomotor adaptation has been thought to be an implicit process that results when a sensory-prediction error signal is used to update a forward model. A striking feature of human competence is the ability to receive verbal instructions and employ strategies to solve tasks; such explicit processes could be used during visuomotor adaptation. Here, we used a novel task design that allowed us to obtain continuous verbal reports of aiming direction while participants learned a visuomotor rotation. We had two main hypotheses: the contribution of explicit learning would be modulated by instruction and the contribution of implicit learning would be modulated by the form of error feedback. By directly assaying aiming direction, we could identify the time course of the explicit component and, via subtraction, isolate the implicit component of learning. There were marked differences in the time courses of explicit and implicit contributions to learning. Explicit learning, driven by target error, was achieved by initially large then smaller explorations of aiming direction biased toward the correct solution. In contrast, implicit learning, driven by a sensory-prediction error, was slow and monotonic. Continuous error feedback reduced the amplitude of explicit learning and increased the contribution of implicit learning. The presence of instruction slightly increased the rate of initial learning and only had a subtle effect on implicit learning. We conclude that visuomotor adaptation, even in the absence of instruction, results from the interplay between explicit learning driven by target error and implicit learning of a forward model driven by prediction error.