Department of Neuroscience, University of Parma, Parma, Italy.
PLoS One. 2012;7(5):e36390. doi: 10.1371/journal.pone.0036390. Epub 2012 May 31.
One of the most important faculties of humans is to understand the behaviour of other conspecifics. The present study aimed at determining whether, in a social context, request gesture and gaze direction of an individual are enough to infer his/her intention to communicate, by searching for their effects on the kinematics of another individual's arm action. In four experiments participants reached, grasped and lifted a bottle filled of orange juice in presence of an empty glass. In experiment 1, the further presence of a conspecific not producing any request with a hand and gaze did not modify the kinematics of the sequence. Conversely, experiments 2 and 3 showed that the presence of a conspecific producing only a request of pouring by holding the glass with his/her right hand, or only a request of comunicating with the conspecific, by using his/her gaze, affected lifting and grasping of the sequence, respectively. Experiment 4 showed that hand gesture and eye contact simultaneously produced affected the entire sequence. The results suggest that the presence of both request gesture and direct gaze produced by an individual changes the control of a motor sequence executed by another individual. We propose that a social request activates a social affordance that interferes with the control of whatever sequence and that the gaze of the potential receiver who held the glass with her hand modulates the effectiveness of the manual gesture. This paradigm if applied to individuals affected by autism disorder can give new insight on the nature of their impairment in social interaction and communication.
人类最重要的能力之一是理解同类的行为。本研究旨在确定在社交情境中，个体的请求手势和注视方向是否足以推断其交流意图，方法是通过搜索它们对另一个体手臂动作的运动学的影响。在四个实验中，参与者在一个空杯子的存在下伸手、抓住并提起装满橙汁的瓶子。在实验 1 中，另一个没有用手和目光发出任何请求的同类的进一步存在并没有改变序列的运动学。相反，实验 2 和 3 表明，只有一个拿着玻璃杯用右手请求倒果汁，或者只用目光请求与同伴交流的同类的存在，分别影响了提起和抓住序列。实验 4 表明，手势和眼神同时出现会影响整个序列。结果表明，个体发出的请求手势和直接注视的存在改变了另一个体执行的运动序列的控制。我们提出，社会请求激活了一种社会可供性，它会干扰任何序列的控制，而用手拿着杯子的潜在接收者的注视会调节手动手势的有效性。如果将这种范式应用于受自闭症障碍影响的个体，可以深入了解他们在社交互动和沟通方面的障碍性质。
