Centre for Neuroscience Studies, Queen’s University Kingston, Ontario, Canada.
J Neurophysiol. 2012 Sep;108(5):1262-9. doi: 10.1152/jn.00263.2012. Epub 2012 Jun 13.
Skilled object lifting requires the prediction of object weight. When lifting new objects, such prediction is based on well-learned size-weight and material-density correlations, or priors. However, if the prediction is erroneous, people quickly learn the weight of the particular object and can use this knowledge, referred to as sensorimotor memory, when lifting the object again. In the present study, we explored how sensorimotor memory, gained when lifting a given object, interacts with well-learned material-density priors when predicting the weight of a larger but otherwise similar-looking object. Different groups of participants 1st lifted 1 of 4 small objects 10 times. These included a pair of wood-filled objects and a pair of brass-filled objects where 1 of each pair was covered in a wood veneer and the other was covered in a brass veneer. All groups then lifted a larger, brass-filled object with the same covering as the small object they had lifted. For each lift, we determined the initial peak rate of change of vertical load-force rate and the load-phase duration, which provide estimates of predicted object weight. Analysis of the 10th lift of the small cube revealed no effects of surface material, indicating participants learned the appropriate forces required to lift the small cube regardless of object appearance. However, both surface material and core material of the small cube affected the 1st lift of the large block. We conclude that sensorimotor memory related to object density can contribute to weight prediction when lifting novel objects but also that long-term priors related to material properties can influence the prediction.
熟练的物体提升需要预测物体的重量。当提起新物体时，这种预测基于经过良好学习的大小-重量和材料密度相关性或先验知识。然而，如果预测错误，人们会很快了解到特定物体的重量，并可以在再次提起该物体时利用这种称为感觉运动记忆的知识。在本研究中，我们探讨了当预测更大但外观相似的物体的重量时，通过提起给定物体获得的感觉运动记忆如何与经过良好学习的材料密度先验知识相互作用。不同组别的参与者首先提起 4 个小物体中的 1 个 10 次。这些物体包括一对填充木材的物体和一对填充黄铜的物体，每对中的 1 个物体覆盖有木贴面，另 1 个物体覆盖有黄铜贴面。然后，所有组都提起了一个较大的、填充黄铜的物体，其覆盖物与他们提起的小物体相同。对于每次提起，我们确定了垂直负载力率的初始峰值变化率和负载相持续时间，这提供了预测物体重量的估计。对小方块的第 10 次提起的分析表明，表面材料没有影响，表明参与者无论物体外观如何，都学会了提起小方块所需的适当力量。然而，小方块的表面材料和核心材料都影响了大方块的第 1 次提起。我们得出结论，与物体密度相关的感觉运动记忆可以有助于提起新物体时的重量预测，但与材料特性相关的长期先验知识也可能影响预测。
