Embodying photorealistic personalized avatars that closely resemble their users has recently become technologically achievable in virtual reality (VR). While previous work highlighted several benefits of personalization, its impact on emotions, a central VR element, remains underexplored. Given their high production cost, assessing the added value of photorealistic personalized avatars is essential before their adoption as a design feature. To address this, we designed and validated (n=302) four virtual environments (VEs) that induce emotions in different quadrants of Russell’s Circumplex Model. Using these VEs, we systematically investigated the impact of avatar type (no avatar, generic avatar, personalized avatar) on perceived emotions and physiological responses (n=51). Generic avatars enhanced valence, arousal, embodiment, presence and selected physiological measures, while personalized avatars further amplified these effects and additionally increased heart rate variability, a marker of self-regulation. Our study demonstrates that photorealistic personalized avatars markedly enhance VR’s capacity to foster emotional engagement.

With the advent of social virtual reality (VR), understanding how avatar personalization impacts users' social behaviour and physiological responses in VR is increasingly important. Deceptive behaviour is particularly relevant, as users can often hide their identity behind generic avatars, which can facilitate deception. We investigated whether avatar personalization and motor control impacted physiological reactions in a Detection-of-Deception task. Twenty participants performed the task with different levels of avatar personalization and motor control over the avatar. While personalization did not impact skin conductance responses, it led to a significant decrease in heart rate, which is an established physiological response associated with deceptive behaviour. This effect was exclusive to personalized avatars and not observed in generic avatars. Personalization and motor control led to increased embodiment, body ownership, agency and presence ratings. Overall, personalized avatars can preserve users’ physiological reactions to key social events, and thus enhance the realism of VR simulations.

Co-located social gaming with players and observers talking to each other is commonplace. However, it becomes less attractive when using virtual reality (VR): while VR increases players’ presence by immersing them in a virtual world, it also shuts out their observing friends. We investigate whether extended reality (XR) can improve the observer experience by giving them agency over their viewpoint in the game and personalizing the representation they see of the player. In a user study, 24 pairs of players and observers experienced co-located VR gaming. Observers either watched the player’s gameplay on a stationary screen i) from the player’s viewpoint or ii) controlling their viewpoint with a gamepad, or on an XR-enabled mobile screen controlling their viewpoint by moving the screen iii) with the player represented as a generic game avatar or iv) a personalized avatar obtained through live player footage augmentation. Results show that giving observers agency over their viewpoint with an XR-enabled mobile screen provides substantial benefits to presence and observers’ overall experience.

Embodied personalized avatars are a promising new tool to investigate moral decision-making by transposing the user into the "middle of the action" in moral dilemmas. Here, we tested whether avatar personalization and motor control could impact moral decision-making, physiological reactions and reaction times, as well as embodiment, presence and avatar perception. Seventeen participants, who had their personalized avatars created in a previous study, took part in a range of incongruent (i.e., harmful action led to better overall outcomes) and congruent (i.e., harmful action led to trivial outcomes) moral dilemmas as the drivers of a semi-autonomous car. They embodied four different avatars (counterbalanced - personalized motor control, personalized no motor control, generic motor control, generic no motor control). Overall, participants took a utilitarian approach by performing harmful actions only to maximize outcomes. We found increased physiological arousal (SCRs and heart rate) for personalized avatars compared to generic avatars, and increased SCRs in motor control conditions compared to no motor control. Participants had slower reaction times when they had motor control over their avatars, possibly hinting at more elaborate decision-making processes. Presence was also higher in motor control compared to no motor control conditions. Embodiment ratings were higher for personalized avatars, and generally, personalization and motor control were perceptually positive features. These findings highlight the utility of personalized avatars and open up a range of future research possibilities that could benefit from the affordances of this technology and simulate, more closely than ever, real-life action.

Embodying virtual twins – photorealistic and personalized avatars – will soon be easily achievable in consumer-grade VR. For the first time, we explored how photorealism and personalization impact self-identification, as well as embodiment, avatar perception and presence. Twenty participants were individually scanned and, in a two-hour session, embodied four avatars (high photorealism personalized, low photorealism personalized, high photorealism generic, low photorealism generic). Questionnaire responses revealed stronger mid-immersion body ownership for the high photorealism personalized avatars compared to all other avatar types, and stronger embodiment for high photorealism compared to low photorealism avatars and for personalized compared to generic avatars. In a self-other face distinction task, participants took significantly longer to pause the face morphing videos of high photorealism personalized avatars, suggesting a stronger self-identification bias with these avatars. Photorealism and personalization were perceptually positive features; how employing these avatars in VR applications impacts users over time requires longitudinal investigation.

Ultrasonic mid-air haptic technologies, which provide haptic feedback through airwaves produced using ultrasound, could be employed to investigate the sense of body ownership and immersion in virtual reality (VR) by inducing the virtual hand illusion (VHI). Ultrasonic mid-air haptic perception has solely been investigated for glabrous (hairless) skin, which has higher tactile sensitivity than hairy skin. In contrast, the VHI paradigm typically targets hairy skin without comparisons to glabrous skin. The aim of this article was to investigate illusory body ownership, the applicability of ultrasonic mid-air haptics, and perceived immersion in VR using the VHI. Fifty participants viewed a virtual hand being stroked by a feather synchronously and asynchronously with the ultrasonic stimulation applied to the glabrous skin on the palmar surface and the hairy skin on the dorsal surface of their hands. Questionnaire responses revealed that synchronous stimulation induced a stronger VHI than asynchronous stimulation. In synchronous conditions, the VHI was stronger for palmar stimulation than dorsal stimulation. The ultrasonic stimulation was also perceived as more intense on the palmar surface compared to the dorsal surface. Perceived immersion was not related to illusory body ownership per se but was enhanced by the provision of synchronous stimulation.