Level of immersion and directed attention in VR environments

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Objective measure - SART. For the current study, we used the Sustained Attention to Response Task (SART) as both an objective measure and a cognitive fatiguing task. Each block began with a set of 18 practice trials to provide feedback on accuracy, followed by 225 experimental trials. The SART demands the activation of the participant’s sustained attention through the pseudo-randomised presentation sequence of 225 digits, within which 10% are a target number (in the current study, the target number was 3). Digits were presented every 1.15 seconds and each digit remained on screen for 250 milli-seconds, followed by a 900-millisecond cross-mask. Participants responded with a key press (spacebar) to all stimuli (numbers 0 to 9) except for the target number (3). With a pseudorandom rotation of digit combinations, and a total of 225 + 18 practice trials, each block lasted approximately 4.8 minutes. Subjective measures. The Short-version Revised Perceived Restorativeness Scale (SRPRS) [63] is the revised version of the original Perceived Restorativeness Scale (PRS) designed by Hartig et al. [64] to measure the recovery of directed attention fatigue within mental fatigue [4]. The 12 items measure three restorative factors (being-away, fascination, and compatibility) identified in the Kaplans’ ART [3, 4, 63]. Items are rated on a 9-point scale (1 = not at all to 9 = a great deal). This questionnaire’s primary utility was to access participants’ subjective restoration experiences with each exposure.

We used the Igroup Presence Questionnaire (IPQ) [67-69] to measure presence after each exposure, since it was found to be sensitive enough to detect differences in presence. The IPQ measures three factors: spatial presence – the relationship between the physical body and the virtual environmental “space”, involvement – the amount of attention de-voted to the VE, and realness – the extent to which the VE is accepted as reality. As a self-report questionnaire, the IPQ consists of 14 statements and questions with each rated on a 7-point scale with varying anchors relevant to each statement/question.

The Immersive Tendency Questionnaire (ITQ) is the revised version [75] of Witmer and Singer’s [37] questionnaire by the same name. We chose to use the revised version because it has an added factor of emotional involvement and absorption. Emotional involvement reflects the affective aspects of a person’s innate immersion tendency, which would make the person more involved. The ITQ is an 18-item self-report questionnaire aimed at measuring participants’ intrinsic immersion tendencies. The ITQ scores were used in the current study as a quasi-independent variable, according to categorised score ranges.

Software/equipment used to create/collect the data: Virtual exposures hardware. The Aftershock MX-15 Pro laptop with a 15.6-inch 144Hz FHD Premium AHVA, and IPS wide colour display (1920 x 1080) was the supporting system for both the non-virtual reality and virtual reality exposures. The virtual reality exposures were mapped by the HTC Vive VR kit’s [78] two wireless sensors placed diagonally from each other either on the table (for the VR-U exposure) or on the ground under the table (for the VR-N exposure) situated in a psychology research laboratory space on the university campus. The sensors were meant to cover a good proportion of the 3 metre by 2 metre room to provide 360 degrees of coverage to track the HMD which would provide 110o field of view with 2160 x 1200 resolution and 90Hz refresh rate during exposures. The hand controls were also tracked but these were only used by the experimenter to set up each exposure. A stereo 3D-surround noise-cancelling gaming headset was used for audio output during all three exposures. Audio clips were selected from the Relax Melodies application [79] and were played by connecting the headphones to an iPhone 6. Audio levels were set at 95 decibels for both nature and urban sounds.

Virtual exposures software. The Atmosphaeres – 360o Virtual Reality Experiences application [80] was downloaded onto the Steam video game platform [81]. The Bavarian Alps video was selected for the VR-N and Non-VR-N exposure. The Non-VR-N exposure clip was a full-computer-screen display of a 6K high-resolution video of the same Bavari-an Alps stock clip on Youtube [80]. The VR-U exposure was the street view of 225 Deans-gate, Manchester, England on the Google Earth VR application [77].

Virtual exposures tactile materials. A 120cm2 faux grass patch was placed on the floor in front of the table and participants were asked to place their feet on and interact with it during the VR-N and Non-VR-N exposures. During the VR-U exposure, the participant was asked to sit on a chair with rollers while holding and interacting with a brain-shaped stress ball during the exposure.

Software/equipment used to manipulate/analyse the data: IBM SPSS v24 was used to analyse the data.