Field (In)dependence Flexibility Following a Virtual Immersion Is Associated With Cybersickness and Sense of Presence

Field dependence–independence (FDI) is a psychological construct determining an individual’s approach of the perception–cognition coupling. In virtual reality (VR) context, several studies suggest that an individual’s perceptive style is susceptible to shift toward a more FI mode through down-weighting of conflicting visual cues. The present study proposes to investigate the potential flexible nature of FDI following a virtual immersion and to assess if this flexibility might be associated with the subjective experience of VR. 86 participants explored a real-world–like virtual environment for approximately 10 min. FDI levels were measured before and after the VR exposure using the rod-and-frame test. Their subjective experience of VR was measured a posteriori (cybersickness and sense of presence) and used in order to build two experimental groups via a cluster analysis. The results showed that only participants with a poor subjective experience of VR (i.e., a low level of sense of presence associated with a high level of cybersickness) significantly shifted to a more FI mode, which is discussed as a sensory re-weighting mechanism. Pragmatical applications are discussed, and future studies are outlined, based on the conclusion that FDI might be more flexible than we thought, which could shed light on the psychophysiology of VR

Off vertical axis rotation motion sickness and field dependence

BACKGROUND: Our study probed the relationship between field dependence and the development of nausea in light and dark during whole-body, off vertical axis rotation (OVAR). METHODS: There were 24 subjects who underwent OVAR at 0.2 Hz, 18 degree tilt. Exposures were undertaken in both light and darkness in sessions spaced 5 d apart in balanced order design. During rotation, nausea was rated at 1-min intervals to a cut off at 20 min or a level of 'moderate nausea' was attained, at which point motion stopped. Before and after OVAR sessions field dependence was rated with the rod and frame test (RFT) with head upright or tilted 28 degree to induce a head-centric bias. RESULTS: Subjects tolerated OVAR longer in the light (mean 13.3 min +/- 6.8 SD) than in darkness (11.1 min +/- 7.2). Motion sickness susceptibility evaluated by questionnaire was inversely correlated with tolerance of OVAR in the light. There was a tendency for subjects who were visual field dependent to fare better with OVAR in the light than in darkness. Subjects whose RFT estimates with head tilted tended to incline the visual vertical to the direction of head tilt better tolerated OVAR in darkness. DISCUSSION: The results suggest that susceptibility, as evaluated by questionnaires probing motion sickness experiences in daily life, is influenced by visual factors. Assessments of sensitivity to reference frames for orientation, either visual or ego-centered, show promise for markers of motion sickness susceptibility according to the visual surround rather than to absolute levels of susceptibility to motion sickness

Does proprioception contribute to the sense of verticality?

International audienceThe representation of the vertical can be assessed by measuring the visual, tactile or perception of the postural vertical (PV). It is well accepted that visceral graviceptors and Golgi tendon receptors contribute to perception of the PV, whereas the role of muscular proprioception (Ia muscle spindles) remains to be clarified. The objective of this study was to analyze whether or not muscular proprioception contributes to the representation of verticality. We hypothesized that the modulation of proprioception by appropriate tendinomuscular vibration may tilt the PV. We present two experiments that explore this hypothesis. PV was firstly measured in the pitch plane in twelve healthy subjects in two conditions: baseline and vibration of both Achilles tendons during six minutes, according to a counterbalanced presentation. PV orientation (mean) and dispersion (standard deviation) were calculated on the six measurements per condition. Vibration of the Achilles tendons induced a systematic backward tilt of PV (2.7 degrees +/- 0.8 degrees on average; P < 10(-3)), and no significant changes regarding PV dispersion. A clear post-effect was found for PV orientation in subjects who started the experiment with the condition vibration on. The possibility that PV could also be modulated by a much shorter duration of vibration (less than 8 s of vibration) was analyzed in a second experiment using a similar general procedure but a simplified experimental plane in other subjects. Again a backward PV tilt was induced by the vibration, but with a magnitude lower than that found in the first experiment, and with no post-effect. Since body geometry was unchanged, these two studies mean that proprioception contributes to the representation of the vertical. In conclusion, this study brings new insights to our understanding of the sense of verticality and contributes to the interpretation of backward falls induced by vibration. The induced backward fall is partly due to alignment of the erect posture with a backward-tilted referential of verticality