The Oculus Rift: a cost-effective tool for studying visual-vestibular interactions in self-motion perception

Abstract

For years now, virtual reality devices have been applied in the field of vision science in an attempt to improve our understanding of perceptual principles underlying the experience of self-motion. Some of this research has been concerned with exploring factors involved in the visually-induced illusory perception of self-motion, known as vection. We examined the usefulness of the cost-effective Oculus Rift in generating vection in seated observers. This device has the capacity to display optic flow in world coordinates by compensating for tracked changes in 3D head orientation. We measured vection strength in three conditions of visual compensation for head movement: compensated, uncompensated, and inversely compensated. During presentation of optic flow, the observer was instructed to make periodic head oscillations (±22° horizontal excursions at approximately 0.53 Hz). We found that vection was best in the compensated condition, and was weakest in the inversely compensated condition. Surprisingly, vection was always better in passive viewing conditions, compared with conditions where active head rotations were performed. These findings suggest that vection is highly dependent on interactions between visual, vestibular and proprioceptive information, and may be highly sensitive to limitations of temporal lag in visual-vestibular coupling using this system.

Keywords: Oculus Rift; self-motion perception; vection; virtual reality; visual perception.

FIGURE 1

An observer wearing the Oculus Rift visor demonstrates the full range of head movements within the yaw plane during the presentation of optic flow in active viewing conditions (A–C). During passive conditions, the observer sat still with their head in a constant forward orientation in yaw (B). A keyboard within arm’s reach provided a comfortable interface for the observer to make psychophysical responses.

FIGURE 2

Mean and standard errors for vection strength ratings obtained in each of the three radial flow display conditions (contralateral, pure, ipsilateral) with either active (blue) or passive (gray) viewing. Note the larger increase in vection strength during ipsilateral oscillation for passive compared with active viewing of the same visual information. Note that the difference in vection strength between active and passive conditions using ipsilateral synchronization (**) was not significant when using contralateral synchronization (ns).

FIGURE 3

Means and standard errors for vection onset latencies obtained in each of the three radial flow display conditions (contralateral, pure, ipsilateral) with either active (blue) or passive (gray) viewing.

FIGURE 4

Raw traces showing yaw (red), pitch (green) and roll (blue) position of the head measured as Euler angles in degrees over time (in seconds) during the first 12 s of a trial performed by a representative naive observer (KT). Note that the principal direction of head rotation is in yaw. Vertical solid and dashed lines indicate estimated troughs and peaks in the positional amplitude of yaw head rotation.