Tatti Fabio, Baud-Bovy Gabriel
Robotics, Brain and Cognitive Sciences Department, Istituto Italiano di Tecnologia, Genoa, Italy.
Faculty of Psychology, Università Vita-Salute San Raffaele, Milan, Italy.
PLoS One. 2018 Feb 23;13(2):e0192754. doi: 10.1371/journal.pone.0192754. eCollection 2018.
When several persons perform a physical task jointly, such as transporting an object together, the interaction force that each person experiences is the sum of the forces applied by all other persons on the same object. Therefore, there is a fundamental ambiguity about the origin of the force that each person experiences. This study investigated the ability of a dyad (two persons) to identify the direction of a small force produced by a haptic device and applied to a jointly held object. In this particular task, the dyad might split the force produced by the haptic device (the external force) in an infinite number of ways, depending on how the two partners interacted physically. A major objective of this study was to understand how the two partners coordinated their action to perceive the direction of the third force that was applied to the jointly held object. This study included a condition where each participant responded independently and another one where the two participants had to agree upon a single negotiated response. The results showed a broad range of behaviors. In general, the external force was not split in a way that would maximize the joint performance. In fact, the external force was often split very unequally, leaving one person without information about the external force. However, the performance was better than expected in this case, which led to the discovery of an unanticipated strategy whereby the person who took all the force transmitted this information to the partner by moving the jointly held object. When the dyad could negotiate the response, we found that the participant with less force information tended to switch his or her response more often.
当几个人共同执行一项体力任务时，比如一起搬运一个物体，每个人所感受到的相互作用力是其他所有人作用于同一物体上的力的总和。因此，对于每个人所感受到的力的来源存在一个基本的模糊性。本研究调查了两人组合识别由触觉设备产生并施加到共同握持物体上的小力方向的能力。在这个特定任务中，根据两个参与者的身体互动方式，两人组合可能以无数种方式分配触觉设备产生的力（外力）。本研究的一个主要目标是了解这两个参与者如何协调他们的行动，以感知施加到共同握持物体上的第三个力的方向。本研究包括一个条件，即每个参与者独立做出反应，以及另一个条件，即两个参与者必须就一个协商好的单一反应达成一致。结果显示了广泛的行为表现。一般来说，外力的分配方式并非能使联合表现最大化。事实上，外力常常分配得非常不均衡，导致其中一人无法获得关于外力的信息。然而，在这种情况下表现比预期更好，这促使发现了一种意想不到的策略，即承担所有力的人通过移动共同握持的物体将此信息传递给伙伴。当两人组合可以协商反应时，我们发现力信息较少的参与者往往更频繁地改变他或她的反应。
