In the second task, normal control subjects didn't have a problem correctly evaluating the situation. The two patients, on the other hand, had great difficulties. They were notably poorer than the control subjects in determining whether the person in the video had guessed correctly the weight of the box correctly, or had been deceived.
Finally, in a further experiment the scientists inverted the task. They asked the patients themselves to lift boxes and filmed them while they did so. During the recording, in some cases, the patients were deceived about the weight of the box before they lifted it. Then, healthy control subjects had to judge, after they saw the video, whether the patient had expected the correct or the false weight. In this task, the control subjects failed, because the sequence of motion of the patient, in the case of the false expectations, did not show the characteristic discrepancy between the preparation for the movement and its carrying out. This means that the patients, because of their lack of self-perception, were unable to adjust their movements to their expectations of the weight of the box. In other words, the patients did not have the option to attune themselves to the weight of the box before trying to pick it up. For the same reason, they were not able to judge other people's expectations based on their movement.
Models of movement, which are activated in the brain when we observe the actions of another person, hold information and knowledge about the way our own body functions. The possibilities and limitations of movement of our own body are the reference from which we process and interpret the actions of another person. In other words, we understand in others that which we can do ourselves, and what we cannot do ourselves, we cannot also understand in othe
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Contact: Dr. Simone Bosbach
bosbach@cbs.mpg.de
44-20-76-79-11-54
Max-Planck-Gesellschaft
5-Oct-2005