vection in virtual environments: psychological and psychophysiological mechanisms

The self-motion illusion (‘vection’) refers to a subjective phenomenon where a stationary observer experiences a compelling sense of illusory self-motion when she/he is exposed to large moving patterns of optic flow. As a part of vestibular dysfunction the self-motion illusion is accompanied by the complex of negative symptoms: vertigo, nausea, vomiting and headache. In recent years the phenomenon of vection has attracted the attention of researchers due to the development of virtual reality systems. In such systems stationary subjects are exposed to the large moving optic flow which leads to the appearance of vection. Despite the wide range of approaches and methods of its assessing there is no generally accepted view about the psychological and psychophysiological mechanisms of its appearance. This review considers various approaches to the study of the vection illusion, methods of its evaluation and various factors affecting its severity. Special attention is paid to the mechanisms of the brain activity underlying the vection perception, which was registered using the neuroimaging technique. This work contains also the analysis of the main factors influencing the vection perception such as technical features of virtual reality systems, individual characteristics of observers, cognitive rules of sensory information processing. A detailed description of psychological and psychophysiological methods allowing evaluating the vection strength is given. At the present understanding the process of the vection perception is an actual problem of theoretical and practical psychology. The experimental results may allow psychologists to solve the binding problem concerning the processes of sensory integration. As to practical application the results would help to develop new methods of counteracting the self-motion sickness for astronautics, pilots and sportsmen.