Vibrotactile inputs to the feet can modulate vection

Vection refers to the illusion of self-motion when a significant portion of the visual field is stimulated by visual flow, while body is still. Vection is known to be strong for peripheral vision stimulation and relatively weak for central vision. In this paper, the results of an experimental study of central linear vection with and without vibrotactile feet stimulation are presented. Three types of vibratory stimuli were used: a sinusoidal signal, pink noise, and a chirp signal. Six subjects faced a screen looking at a looming visual flow that suggested virtual forward motion. The results showed that the sensation of self-motion happened faster and its intensity was the strongest for sinusoidal vibrations at constant frequency. For some subjects, a vibrotactile stimulus with an increasing frequency (a chirp) elicited as well a stronger vection. The strength of sensation of self-motion was the lowest in the cases when pink noise vibrations and no vibrotactile stimulation accompanied the visual flow stimulation. Possible application areas are mentioned.