Generalization of Dexterous Manipulation Is Sensitive to the Frame of Reference in Which It Is Learned.
Generalization of Dexterous Manipulation Is Sensitive to the Frame of Reference in Which It Is Learned.
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DOI：
10.1371/journal.pone.0138258
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Gordon AM
中科院分区：
文献类型：
--
作者：
Marneweck M;Knelange E;Lee-Miller T;Santello M;Gordon AM
研究表明，在特定方位内产生的对具有不对称质量分布的物体的操纵的内部表征不能推广到新的方位，即，受试者在物体旋转180°后，在他们第一次抓取-举起物体的尝试中未能阻止物体滚动。这表明，这些操作的表示是特定于它们形成的参照系的。然而，由于将对象旋转180°会修改对象与身体以及对象与手之间关系，因此尚不清楚该参考系是特定于手、身体还是两者。对于上述未能概括学习的操作的另一种未经检验的解释是，无论学习操作的参考系是保持还是修改，任何旋转都会扰乱抓取性能。我们考察了旋转(1)保持和(2)修改物体和物体之间的关系，以及物体和手之间的关系，对学习的具有不对称质量分布的物体的两位数操纵的概括性的影响。在保持物体和身体以及物体和手之间的关系的旋转之后(例如，将物体和受试者旋转180°)，受试者继续使用适当的手指位置和负载力分布，从而产生足够的补偿力矩来最大限度地减少物体滚动。相反，在改变了(1)物体和手之间的关系(例如，将手旋转到相反的物体一侧)、(2)物体和身体(例如，旋转对象和手180°)或(3)两者(例如，将对象旋转180°)之间的关系之后，受试者使用与旋转前相同但不适当的手指位置和负载力分布。因此，补偿性力矩不足以防止大型物体滚动。这些发现表明，对具有不对称质量分布的物体的习得操纵的表征是特定于学习它们的身体和手参考系的。
Studies have shown that internal representations of manipulations of objects with asymmetric mass distributions that are generated within a specific orientation are not generalizable to novel orientations, i.e., subjects fail to prevent object roll on their first grasp-lift attempt of the object following 180° object rotation. This suggests that representations of these manipulations are specific to the reference frame in which they are formed. However, it is unknown whether that reference frame is specific to the hand, the body, or both, because rotating the object 180° modifies the relation between object and body as well as object and hand. An alternative, untested explanation for the above failure to generalize learned manipulations is that any rotation will disrupt grasp performance, regardless if the reference frame in which the manipulation was learned is maintained or modified. We examined the effect of rotations that (1) maintain and (2) modify relations between object and body, and object and hand, on the generalizability of learned two-digit manipulation of an object with an asymmetric mass distribution. Following rotations that maintained the relation between object and body and object and hand (e.g., rotating the object and subject 180°), subjects continued to use appropriate digit placement and load force distributions, thus generating sufficient compensatory moments to minimize object roll. In contrast, following rotations that modified the relation between (1) object and hand (e.g. rotating the hand around to the opposite object side), (2) object and body (e.g. rotating subject and hand 180°), or (3) both (e.g. rotating the subject 180°), subjects used the same, yet inappropriate digit placement and load force distribution, as those used prior to the rotation. Consequently, the compensatory moments were insufficient to prevent large object rolls. These findings suggest that representations of learned manipulation of objects with asymmetric mass distributions are specific to the body- and hand-reference frames in which they were learned.