Observation of object lifting allows updating of internal object representations for object weight, in turn enabling accurate scaling of fingertip forces when lifting the same object. Here, we investigated whether lift observation also enables updating of internal representations for an object's weight distribution. We asked participants to lift an inverted T-shaped manipulandum, of which the weight distribution could be changed, in turns with an actor. Participants were required to minimize object roll (i.e. 'lift performance') during lifting and were allowed to place their fingertips at self-chosen locations. The center of mass changed unpredictably every third to sixth trial performed by the actor and participants were informed that they would always lift the same weight distribution as the actor. Participants observed either erroneous (i.e. object rolling towards its heavy side) or skilled (i.e. minimized object roll) lifts. Lifting performance after observation was compared to lifts without prior observation and to lifts after active lifting, which provided haptic feedback about the weight distribution. Our results show that observing both skilled and erroneous lifts convey an object's weight distribution similar to active lifting, resulting in altered digit positioning strategies. However, minimizing object roll on novel weight distributions was only improved after observing error lifts and not after observing skilled lifts. In sum, these findings suggest that although observing motor errors and skilled motor performance enables updating of digit positioning strategy, only observing error lifts enables changes in predictive motor control when lifting objects with unexpected weight distributions.

中文翻译：

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提升观察传达物体重量分布，但部分增强了预测性提升计划

对物体提升的观察允许更新物体重量的内部物体表示，从而在提升同一物体时能够准确缩放指尖力。在这里，我们调查了提升观察是否也能够更新对象权重分布的内部表示。我们要求参与者与演员轮流举起一个倒置的 T 形操作器，其重量分布可以改变。参与者被要求在提升过程中尽量减少物体滚动（即“提升性能”），并允许将他们的指尖放在自己选择的位置。演员每进行三次到第六次试验，重心就会发生不可预测的变化，参与者被告知他们将始终举起与演员相同的重量分布。参与者观察到错误的（即物体向其沉重的一侧滚动）或熟练的（即最小的物体滚动）提升。将观察后的举重性能与没有事先观察的举重和主动举重后的举重进行比较，这提供了关于重量分布的触觉反馈。我们的结果表明，观察熟练和错误的举重传递类似于主动举重的物体的重量分布，导致数字定位策略的改变。然而，在新的重量分布上最小化物体滚动只有在观察到错误提升后才能得到改善，而不是在观察到熟练的提升后。总之，这些发现表明，虽然观察运动错误和熟练的运动表现能够更新手指定位策略，