Psychophysical scaling of circular vection (CV) produced by optokinetic (OKN) motion: individual differences and effects of practice.

Vection (V) refers to the compelling visual illusion of self-motion experienced by stationary individuals when viewing moving visual surrounds. The phenomenon is of theoretical interest because of its relevance for understanding the neural basis of ordinary self-motion perception, and of practical importance because it is the experience that makes simulation, virtual reality displays, and entertainment devices more vicarious. This experiment was performed to address whether an optokinetically induced vection illusion exhibits monotonic and stable psychometric properties and whether individuals differ reliably in these (V) perceptions. Subjects were exposed to varying velocities of the circular vection (CV) display in an optokinetic (OKN) drum 2 meters in diameter in 5 one-hour daily sessions extending over a 1 week period. For grouped data, psychophysical scalings of velocity estimates showed that exponents in a Stevens' type power function were essentially linear (slope = 0.95) and largely stable over sessions. Latencies were slightly longer for the slowest and fastest induction stimuli, and the trend over sessions for average latency was longer as a function of practice implying time course adaptation effects. Test-retest reliabilities for individual slope and intercept measures were moderately strong (r = 0.45) and showed no evidence of superdiagonal form. This implies stability of the individual circularvection (CV) sensitivities. Because the individual CV scores were stable, reliabilities were improved by averaging 4 sessions in order to provide a stronger retest reliability (r = 0.80). Individual latency responses were highly reliable (r = 0.80). Mean CV latency and motion sickness symptoms were greater in males than in females. These individual differences in CV could be predictive of other outcomes, such as susceptibility to disorientation or motion sickness, and for CNS localization of visual-vestibular interactions in the experience of self-motion.

[1]  I. Howard,et al.  Circularvection about earth-horizontal axes in bilateral labyrinthine-defective subjects. , 1989, Acta oto-laryngologica.

[2]  J. F. Brown.  The visual perception of velocity , 1931 .

[3]  R S Kennedy,et al.  Symptomatology under storm conditions in the North Atlantic in control subjects and in persons with bilateral labyrinthine defects. , 1968, Acta oto-laryngologica.

[4]  A Straube,et al.  Importance of the visual and vestibular cortex for self-motion perception in man (circularvection). , 1987, Human neurobiology.

[5]  E. Wist,et al.  The spatial frequency effect on perceived velocity , 1976, Vision Research.

[6]  R. Stern,et al.  Vasopressin and oxytocin responses to illusory self-motion and nausea in man. , 1990, The Journal of clinical endocrinology and metabolism.

[7]  J Dichgans,et al.  Visual-vestibular interaction and motion perception. , 1972, Bibliotheca ophthalmologica : supplementa ad ophthalmologica.

[8]  George J. Andersen,et al.  Induced self-motion in central vision. , 1985 .

[9]  Magnitude estimation of visual velocity. , 1972, The Journal of psychology.

[10]  R S Kennedy,et al.  Transfer of perceptual-motor training and the space adaptation syndrome. , 1987, Aviation, space, and environmental medicine.

[11]  S. S. Stevens.  On the psychophysical law. , 1957, Psychological review.

[12]  H. Rachlin.  Scaling subjective velocity, distance, and duration , 1966 .

[13]  Margaret D. Nolan,et al.  Vection and simulator sickness. , 1990, Military psychology : the official journal of the Division of Military Psychology, American Psychological Association.