Head-mounted displays (HMDs) are increasingly available to users after the launch of new-generation consumer devices. Moreover, mobile HMDs such as Samsung Gear VR and Google Daydream View allow users to experience VR through a smartphone, without requiring connection to a PC. Commercial applications for mobile HMDs exploit different techniques to perform menu selection tasks. This paper contrasts the two most used techniques, i.e., dwell-based and touchpad-based selection, which were not experimentally compared before. We consider different versions of a menu pointing and selection task in which participants interacted with a Samsung Gear VR. Results show that participants were slower with the dwell-based technique rather than the touchpad-based technique. However, the dwell-based technique led to fewer errors and was perceived as more usable, more comfortable and less fatiguing than the touchpad-based technique. We also evaluated two different active areas for the selection, discussing the results.

The computational capabilities of today's smartphones make it possible to take advantage of mobile three-dimensional (3-D) maps to support navigation in the physical world. In particular, 3-D maps might be useful to facilitate indoor wayfinding in large and complex buildings, where the typical orientation cues (e.g., street names) and location tracking technologies that can be used outdoors are unavailable. The use of mobile 3-D maps for indoor wayfinding is still largely unexplored and research on how to best design such tools has been scarce to date. One overlooked but important design decision for 3-D maps concerns the perspective from which the map content should be displayed, with first-person and third-person perspectives being the two major options. This paper presents a user study involving wayfinding tasks in a large and complex building, comparing a mobile 3-D map with first-person perspective, a mobile 3-D map with third-person perspective, and a traditional mobile 2-D map. The first-person perspective shows the mobile 3-D map of the building from a floor-level egocentric point of view, whereas the third-person perspective shows the surroundings of the user from a fixed distance behind and above her position. Results of the study reveal that the mobile 3-D map with third-person perspective leads to shorter orientation time before walking, better clarity ratings, lower workload, mental demand and effort scores, and higher preference score compared to the mobile 3-D map with first-person perspective. Moreover, it leads to shorter orientation time before walking, better pleasantness ratings, lower mental demand scores, and higher preference score compared to the mobile 2-D map.

In affective computing, detection of stress and negative emotions with physiological measures typically employs well-known signals such as skin conductance, activity of cheeks and forehead muscles, heart rate or heart rate variability. However, psychophysiology experiments in the literature offer additional measures (such as eye-blink startle response) not yet exploited in affective computing applications. Procedures to elicit eye-blink startle responses are often based on acoustic stimuli, in particular short bursts of intense white noise. Unfortunately, following this approach in affective computing applications would not be natural, because the artificial white noise bursts would be intrusive sounds unrelated to the user experience. They would thus distract the user from the meaningful events in the application and user's (conscious or unconscious) attempts to relate those events to the artificial stimuli would be unsuccessful and frustrating, making the stimuli detrimental to the user experience. Our research aims at exploring if sounds that have a meaningful relation with the events in the application could be used as an alternative to white noise bursts. The study we present in this paper compares physiological responses of users of a 3D virtual environment in two conditions (measurement of eye-blink startle response to white noise or to an alternative sound that is related to the experience), showing that the two types of acoustic stimuli produce a similar intensity of startle response. This result suggests that eye-blink startle response could be used in natural ways to extend the set of physiological measures employed in affective computing.