Data from: Visuomotor adaptation: how forgetting keeps us conservative

Even when provided with feedback after every movement, adaptation levels off before biases are completely removed. Incomplete adaptation has recently been attributed to forgetting: the adaptation is already partially forgotten by the time the next movement is made. Here we test whether this idea is correct. If so, the final level of adaptation is determined by a balance between learning and forgetting. Because we learn from perceived errors, scaling these errors by a magnification factor has the same effect as subjects increasing the amount by which they learn from each error. In contrast, there is no reason to expect scaling the errors to affect forgetting. The magnification factor should therefore influence the balance between learning and forgetting, and thereby the final level of adaptation. We found that adaptation was indeed more complete for larger magnification factors. This supports the idea that incomplete adaptation is caused by part of what has been learnt quickly being forgotten.即便每次动作后均可获得反馈，适应性调整也会在偏差被完全消除前趋于平台期。近期有研究将不完全适应性归因于遗忘现象：当下一次动作启动时，已形成的适应性调整已出现部分遗忘。本研究旨在验证该假说是否成立。若该假说成立，则适应性调整的最终水平由学习与遗忘之间的动态平衡所决定。由于人类会从感知到的误差中进行学习，将误差按放大因子（magnification factor）缩放，其效果等价于被试提升了从单次误差中获得的学习量。与之相对，尚无合理依据表明误差缩放会对遗忘过程产生影响。因此，放大因子理应通过影响学习与遗忘间的平衡，进而改变适应性调整的最终水平。本研究发现，当放大因子取值更大时，适应性调整的完成度确实更高。该结果佐证了“不完全适应性源于已习得的调整内容被快速遗忘”这一假说。