Egocentric references and human spatial orientation in microgravity. I. Perception of complex tactile stimuli.

This paper is devoted to the results of the "tactile matrix" experiment performed during the second French-Soviet spaceflight (project Aragatz). The perception of the orientation of complex tactile stimuli (letters and digits) applied to different skin areas under varied conditions was studied. The task of interpretation of complex tactile stimuli was not affected by the absence of the gravitational vertical, although this task is closely associated with mechanisms for the perception of body configuration, as well as the spatial orientation of different body parts. The number of errors made under conditions of weightlessness was often even less than on Earth. The results confirm the high stability of the egocentric reference system and provide evidence that this system is based on a body scheme which cannot be easily modified by changing external conditions.