Perceived timing of active head movement at different speeds

Quantifying time perception during virtual reality gameplay using a multimodal biosensor-instrumented headset: a feasibility study

We have all experienced the sense of time slowing down when we are bored or speeding up when we are focused, engaged, or excited about a task. In virtual reality (VR), perception of time can be a key aspect related to flow, immersion, engagement, and ultimately, to overall quality of experience. While several studies have explored changes in time perception using questionnaires, limited studies have attempted to characterize them objectively. In this paper, we propose the use of a multimodal biosensor-embedded VR headset capable of measuring electroencephalography (EEG), electrooculography (EOG), electrocardiography (ECG), and head movement data while the user is immersed in a virtual environment. Eight gamers were recruited to play a commercial action game comprised of puzzle-solving tasks and first-person shooting and combat. After gameplay, ratings were given across multiple dimensions, including (1) the perception of time flowing differently than usual and (2) the gamers losing sense of time. Several features were extracted from the biosignals, ranked based on a two-step feature selection procedure, and then mapped to a predicted time perception rating using a Gaussian process regressor. Top features were found to come from the four signal modalities and the two regressors, one for each time perception scale, were shown to achieve results significantly better than chance. An in-depth analysis of the top features is presented with the hope that the insights can be used to inform the design of more engaging and immersive VR experiences.

Can the Perceived Timing of Multisensory Events Predict Cybersickness?

Humans are constantly presented with rich sensory information that the central nervous system (CNS) must process to form a coherent perception of the self and its relation to its surroundings. While the CNS is efficient in processing multisensory information in natural environments, virtual reality (VR) poses challenges of temporal discrepancies that the CNS must solve. These temporal discrepancies between information from different sensory modalities leads to inconsistencies in perception of the virtual environment which often causes cybersickness. Here, we investigate whether individual differences in the perceived relative timing of sensory events, specifically parameters of temporal-order judgement (TOJ), can predict cybersickness. Study 1 examined audiovisual (AV) TOJs while Study 2 examined audio-active head movement (AAHM) TOJs. We deduced metrics of the temporal binding window (TBW) and point of subjective simultaneity (PSS) for a total of 50 participants. Cybersickness was quantified using the Simulator Sickness Questionnaire (SSQ). Study 1 results (correlations and multiple regression) show that the oculomotor SSQ shares a significant yet positive correlation with AV PSS and TBW. While there is a positive correlation between the total SSQ scores and the TBW and PSS, these correlations are not significant. Therefore, although these results are promising, we did not find the same effect for AAHM TBW and PSS. We conclude that AV TOJ may serve as a potential tool to predict cybersickness in VR. Such findings will generate a better understanding of cybersickness which can be used for development of VR to help mitigate discomfort and maximize adoption.

Influence of Sensory Conflict on Perceived Timing of Passive Rotation in Virtual Reality

Integration of incoming sensory signals from multiple modalities is central in the determination of self-motion perception. With the emergence of consumer virtual reality (VR), it is becoming increasingly common to experience a mismatch in sensory feedback regarding motion when using immersive displays. In this study, we explored whether introducing various discrepancies between the vestibular and visual motion would influence the perceived timing of self-motion. Participants performed a series of temporal-order judgements between an auditory tone and a passive whole-body rotation on a motion platform accompanied by visual feedback using a virtual environment generated through a head-mounted display. Sensory conflict was induced by altering the speed and direction by which the movement of the visual scene updated relative to the observer's physical rotation. There were no differences in perceived timing of the rotation without vision, with congruent visual feedback and when the speed of the updating of the visual motion was slower. However, the perceived timing was significantly further from zero when the direction of the visual motion was incongruent with the rotation. These findings demonstrate the potential interaction between visual and vestibular signals in the temporal perception of self-motion. Additionally, we recorded cybersickness ratings and found that sickness severity was significantly greater when visual motion was present and incongruent with the physical motion. This supports previous research regarding cybersickness and the sensory conflict theory, where a mismatch between the visual and vestibular signals may lead to a greater likelihood for the occurrence of sickness symptoms.