We are slowly getting there: Towards Continuous Assessment of Presence in Virtual Environments

The phenomenon of non-mediation is an important factor in virtual experiences. Users seem to ignore their physical surroundings and become present in the virtual environment (VE). Assessing presence in VEs with continuous measures is an ongoing effort both to complement the data provided by self-report measures and to identify specific events during virtual experiences that disrupt presence (“breaks in presence”; BIPs, Slater & Steed, 2002). Early studies employed self-report measures for BIPs, but have also identified specific psychophysiological reactions bearing the potential to develop a continuous measure—the nature of these reactions, however, has been unclear. We argue that BIPs can be considered as orienting responses (ORs; Sokolov, 1963) as users interact with VEs based on dedicated mental models and direct all their attention to virtual stimuli. When a new virtual stimulus is incompatible with these mental models, an OR is triggered, directing user attention at the source of the stimulus to determine its cause. ORs have been linked to psychophysiological reactions (Bradley, 2009) similar to the ones reported for BIPs. We designed a series of three studies to investigate this account to BIPs. Two studies are already complete, while a third study is currently being conducted. In all studies, users played Skyrim (Bethesda, 2011) modified to include stimuli that can be considered as BIPs not belonging to the VE. We measured psychophysiological responses using ECG and GSR. In study 1 (N = 31) participants played for M = 82.08 minutes (SD = 34.23) and encountered ten different types of BIP stimuli (e.g. error message, game crash) determined empirically through a prestudy. In line with previous literature on ORs, we found significant responses in ECG and GSR for all BIPs with a clearly defined stimulus onset. Additionally, we found a habituation effect of repeated exposure to the error message consistent with habituation of orienting. Analysis of blinking activity showed prolonged intervals during BIPs consistent with the information acquisition function of ORs. In study 2 (N = 69) participants played for M = 22.02 minutes (SD = 7.1). We employed a modified secondary-task reaction time (STRT) procedure in addition to psychophysiological measurements to compare ORs towards a game-related stimulus with ORs towards a BIP-stimulus. By pressing a footswitch, participants had to react to a crying baby, embedded into the game’s narrative, or a similarly pitched interference pattern of two sinewaves. Although we expected faster reaction times for game-related stimuli, we found similar reaction times for both types of stimuli. However, we could replicate the psychophysiological patterns from study 1. Both sounds equally elicited ORs with game-related stimuli leading to stronger responses and habituation. The data from the first two studies indicate that BIPs can be considered a type of OR, suggesting a promising avenue towards continuous measurement of presence. Following a similar design, Study 3 employs a STRT task based on more intricate considerations of the processes in human working memory (Oberauer, 2009). Additionally, pupil dilation is being assessed to investigate cognitive load associated with responses to game-related stimuli and BIPs.