The effect of non-humanoid size cues for the perception of physics plausibility in virtual reality

Abstract. This thesis studies the relationship between inhabited scale and the perception of physics in virtual reality. The work builds upon the findings of an earlier study on the perception of physics when a user is virtually scaled down. One of these studies involved having users evaluate the movement of soda tabs dropped and thrown by a doll-sized humanoid robot when the user was either scaled normally or scaled down. This thesis aimed to replicate the study with the alteration of using a cat as a more natural, non-humanoid actor to throw the soda tabs. Similarly to the previous study, it was hypothesized that participants would prefer realistic physics when at a normal scale and unrealistic physics when virtually scaled down. For this, a photo-realistic virtual environment and a realistic animated cat were created. The method of study involved participants observing the cat drop soda tabs from an elevated platform. Participants experienced the event with both realistic physics (dubbed true physics) and unrealistic physics (dubbed movie physics) and were asked to choose the one they perceived as most expected. This method was repeated for participants at a normal scale and when they were virtually scaled down. The study recruited 40 participants, and the results were unable to confirm either hypothesis and were unable to find a preference towards either physics preference. The result differs from Pouke’s study which was able to find a preference for movie physics when participants were virtually scaled down. This thesis discusses the findings and also uses supplementary gathered data to offer potential rationalizations and insights into the received result.Ei-humanoidin koko vihjeiden vaikutus fysiikan uskottavuuden havainnollistamiseen virtuaalitodellisuudessa. Tiivistelmä. Tämä diplomityö tutkii käyttäjän koon ja fysiikan havainnollistamisen välistä suhdetta virtuaalitodellisuudessa. Tämä työ perustuu Pouken tekemiin löytöihin fysiikan havaitsemisessa kun käyttäjää virtuaalisesti kutistetaan virtuaalitodellisuudessa. Yhdessä näistä tutkimuksista käyttäjiä kysyttiin arvioimaan nukkekokoisen humanoidirobotin heittämien tölkinrenkaiden liikettä kun käyttäjä oli joko normaalin kokoinen tai virtuaalisesti kutistettu pieneksi. Tämän työn tavoitteena oli toistaa kyseinen tutkimus, mutta vaihtaa humanoidirobotin tilalle kissa toimimaan luonnollisempana tekijänä. Kuten aiemassa tutkimuksessa, tämän työn hypoteesiksi oletetaan että käyttäjät suosivat todenmukaista fysiikkaa normaalissa mittakaavassa ja epärealistista fysiikkaa kutistettuna. Tämän selvittämistä varten luotiin fotorealistinen virtuaaliympäristö sekä realistisesti animoitu kissa. Tutkimuksen menetelmässä osallistujat tarkkailivat kissaa, joka pudotti tölkinrenkaita korotetulta alustalta. Osallistujat kokivat tapahtuman sekä realistisella fysiikalla että epärealistisella fysiikalla, ja heitä pyydettiin valitsemaan se, jonka he pitivät odotetuimpana. Tämä menetelmä toistettiin osallistujille normaalissa mittakaavassa ja kutistettuna. Tutkimukseen rekrytoitiin 40 osallistujaa, ja tulokset eivät pystyneet vahvistamaan kumpaakaan hypoteesia eivätkä löytäneet mieltymystä kumpaankaan fysiikkaan. Tulos eroaa edellisestä tutkimuksesta, joka löysi mieltymyksen epärealistiseen fysiikkaan, kun osallistujia oli kutistettuna. Tässä työssä keskustellaan tästä havainnosta sekä tarjotaan mahdollisia rationalisointeja ja muita löydöksiä saaduista täydentävistä tuloksista

Augmenting Immersive Telepresence Experience with a Virtual Body

We propose augmenting immersive telepresence by adding a virtual body, representing the user's own arm motions, as realized through a head-mounted display and a 360-degree camera. Previous research has shown the effectiveness of having a virtual body in simulated environments; however, research on whether seeing one's own virtual arms increases presence or preference for the user in an immersive telepresence setup is limited. We conducted a study where a host introduced a research lab while participants wore a head-mounted display which allowed them to be telepresent at the host's physical location via a 360-degree camera, either with or without a virtual body. We first conducted a pilot study of 20 participants, followed by a pre-registered 62 participant confirmatory study. Whereas the pilot study showed greater presence and preference when the virtual body was present, the confirmatory study failed to replicate these results, with only behavioral measures suggesting an increase in presence. After analyzing the qualitative data and modeling interactions, we suspect that the quality and style of the virtual arms, and the contrast between animation and video, led to individual differences in reactions to the virtual body which subsequently moderated feelings of presence.Comment: Accepted for publication in Transactions in Visualization and Computer Graphics (TVCG), to be presented in IEEE VR 202

A Qualitative Case Study on Deconstructing Presence for Young Adults and Older Adults

In this paper, we present the results of an exploratory qualitative case study on presence experienced by groups of young adults and older adults during their use of an interactive virtual reality application mixing realistic and fantasy elements. In contrast to most previous studies, we do not focus on a set of predetermined factors but instead adopt an open-ended qualitative approach to identify emerging factors from the users' experiences. We then analyze these factors against the place illusion/plausibility illusion (PI/PSI) framework of Skarbez, Neyret, et al. (2017) to investigate whether PI and PSI, as well as their contributing factors, can be separated. According to our findings, a user can experience PI and PSI independently from each other; however, they often appeared intermixed when investigated on the scope of the whole experience. Breaks in presence, as well as breaks in plausibility, could mostly, but not entirely, be attributed to immersion and coherence factors, respectively. An interesting finding is that both participant groups turned out to have two subgroups interpreting their experience with a particular frame of reference of differing expectations. These frames of reference affected not only PSI, as expected, but PI as well, suggesting that coherence could be a contributing factor to both PI and PSI. Our contribution adds to the relatively small body of research investigating the separation of PI and PSI. Our exploratory findings can be utilized as directions for designing future confirmatory studies.Peer reviewe

A qualitative case study on deconstructing presence for young adults and older adults

Abstract In this paper, we present the results of an exploratory qualitative case study on presence experienced by groups of young adults and older adults during their use of an interactive virtual reality application mixing realistic and fantasy elements. In contrast to most previous studies, we do not focus on a set of predetermined factors but instead adopt an open-ended qualitative approach to identify emerging factors from the users’ experiences. We then analyze these factors against the place illusion/plausibility illusion (PI/PSI) framework of Skarbez, Neyret, et al. (2017) to investigate whether PI and PSI, as well as their contributing factors, can be separated. According to our findings, a user can experience PI and PSI independently from each other; however, they often appeared intermixed when investigated on the scope of the whole experience. Breaks in presence, as well as breaks in plausibility, could mostly, but not entirely, be attributed to immersion and coherence factors, respectively. An interesting finding is that both participant groups turned out to have two subgroups interpreting their experience with a particular frame of reference of differing expectations. These frames of reference affected not only PSI, as expected, but PI as well, suggesting that coherence could be a contributing factor to both PI and PSI. Our contribution adds to the relatively small body of research investigating the separation of PI and PSI. Our exploratory findings can be utilized as directions for designing future confirmatory studies

The body scaling effect and its impact on physics plausibility

Abstract In this study we investigated the effect of body ownership illusion-based body scaling on physics plausibility in Virtual Reality (VR). Our interest was in examining whether body ownership illusion-based body scaling could affect the plausibility of rigid body dynamics similarly to altering VR users’ scale by manipulating their virtual interpupillary distance and viewpoint height. The procedure involved the conceptual replication of two previous studies. We investigated physics plausibility with 40 participants under two conditions. In our synchronous condition, we used visuo-tactile stimuli to elicit a body ownership illusion of inhabiting an invisible doll-sized body on participants reclining on an exam table. Our asynchronous condition was otherwise similar, but the visuo-tactile stimuli were provided asynchronously to prevent the onset of the body ownership illusion. We were interested in whether the correct approximation of physics (true physics) or physics that are incorrect and appearing as if the environment is five times larger instead (movie physics) appear more realistic to participants as a function of body scale. We found that movie physics did appear more realistic to participants under the body ownership illusion condition. However, our hypothesis that true physics would appear more realistic in the asynchronous condition was unsupported. Our exploratory analyses revealed that movie physics were perceived as plausible under both conditions. Moreover, we were not able to replicate previous findings from literature concerning object size estimations while inhabiting a small invisible body. However, we found a significant opposite effect regarding size estimations; the object sizes were on average underestimated during the synchronous visuo-tactile condition when compared to the asynchronous condition. We discuss these unexpected findings and the potential reasons for the results, and suggest avenues for future research

Augmenting immersive telepresence experience with a virtual body

Abstract We propose augmenting immersive telepresence by adding a virtual body, representing the user’s own arm motions, as realized through a head-mounted display and a 360-degree camera. Previous research has shown the effectiveness of having a virtual body in simulated environments; however, research on whether seeing one’s own virtual arms increases presence or preference for the user in an immersive telepresence setup is limited. We conducted a study where a host introduced a research lab while participants wore a head-mounted display which allowed them to be telepresent at the host’s physical location via a 360-degree camera, either with or without a virtual body. We first conducted a pilot study of 20 participants, followed by a pre-registered 62 participant confirmatory study. Whereas the pilot study showed greater presence and preference when the virtual body was present, the confirmatory study failed to replicate these results, with only behavioral measures suggesting an increase in presence. After analyzing the qualitative data and modeling interactions, we suspect that the quality and style of the virtual arms, and the contrast between animation and video, led to individual differences in reactions to the virtual body which subsequently moderated feelings of presence