Transformation - Learning and performance
The research of the group is guided by practical problems in minimally-invasive surgery. This applied perspective suggests the study of a certain kind of transformations. In endoscopic surgery the tip of the instrument moves in the direction opposite to that of the hand – this is the "fulcrum effect". In addition there is a variable gain, that is, the ratio of the amplitudes of the tip and of the hand varies; the gain is the larger the further the instrument is pushed through the opening in the skin. Adjustments to a continuously varying visuo-motor gain have not yet been studied. The analysis of movements with a lever, which can be rotated and shifted, suggests a number of additional questions. For example, which kind of reference system is used for motor control? This question is suggested because the lever can be seen as the physical implementation of a polar coordinate system, with the pole in the pivot (rather than in the start location of a movement or at some point between shoulder and eye of the moving person).
The applied perspective suggests the study of a second class of transformations which have received only little attention thus far. The pictures of a movement of a tool, which are shown on a monitor (e. g. the movement of a tip of a surgical instrument), can be taken from different perspectives. This results in distortions, that is, nonlinear transformations. According to unpublished results learned nonlinear transformations are labile and tend to regress toward linear transformations.