The Effect of Haptic Interaction Illusion in a VR Environment on Trust in a Virtual Teammate

Assigned Human-Computer Interaction Bachelor Thesis No Affiliation

Introduction

The ongoing digitalization is increasingly transforming the nature of interpersonal communication. As a result, meetings in both business and private contexts are more frequently taking place in digital forms. Virtual realities (VR) enhance presence and can simulate many aspects of a real personal meeting well, especially auditory and visual cues. However, one remaining challenge is the realistic representation of touch. This could have a major influence as a form of non-verbal communication but is currently under-researched. Studies show that even small touches, such as a hand touch, can increase the willing to give tips [1]. This leads to the related question of how great the influence of touch on trust is, and whether this can be replicated in VR.

Related Work

Examining the current literature on interpersonal touch and trust, the focus is often on the financial aspect. However, trust is a complex construct that depends on the relationship between the parties and the context. Individual experiences and the general willingness to trust strangers also have an influence. This leads to very different individual behaviours that plays a crucial role in trusting strangers [2]. Law et al. (2021) conducted a passive observational study based on showing videos, to research whether trust in a robot increases when it touches a human on the shoulder. The results indicated a significant effect of such a touch on trust. Moreover, the study investigated whether a handshake at the beginning of the video further enhances this trust. Due to a small sample size, these results were not statistically significant, although the descriptive data shows a positive effect of the handshake on trust in the robot. Lin et al. (2023) investigated trust in a virtual human within a virtual maze environment. These results revealed that subjects who described the virtual human as trustworthy were significantly more likely to seek for advice from it. These findings suggest that the frequency of participants asking the virtual human for help, is a reliable approximation of measuring trust.

Motivation

Research on trust primarily relies on experimental designs with game-theoretical aspect, such as investment games [5]. However, trust in everyday and private situations is less explored. Virtual touches can play an important role in various digital application areas, such as therapies or social networks. Trust is influenced by many individual factors [2][5], including the general tendency to trust in new situations as well as the weighing of risks and benefits in a specific situation and the associated vulnerability. In addition, there are major interpersonal differences regarding the perception and acceptance of touch. Some people find touch uncomfortable and avoid it [6]. With this in mind, the shoulder is chosen as the location of touch in this study, as it is considered a less vulnerable part of the body. Furthermore, trust will be investigated in a low-risk and natural situation and an adequate sample size will be selected to be able to make more generalizable statements.

Research Question

This leads to the research question of how virtual touches on the shoulder influence trust in a virtual agent. This question has not been sufficiently addressed in the literature review. Based on the authors mentioned above, it is hypothesized that a positive effect is expected with proper implementation.

Methodology

To examine whether haptic interaction can improve trust in a virtual agent within a VR environment, an experimental study will be set up. According to Evans & Krueger (2009), the participant will be deliberately exposed to a low risk and high uncertainty. For this, a cooperative knowledge-based bar-quiz will be used and the participant will team up with a virtual agent. The study will investigate how the behaviour of the agents affects the respondents’ trust.

Study Design

Hereby touch represents the independent variable. Within the study, two conditions will be examined: one condition with haptic interaction (touch) and one condition without haptic interaction (no-touch). The participants wear a vest equipped with vibrations motors to simulate the sensation of touch. Since a haptic vest is an unfamiliar output device, it will be worn in both conditions as a controlled variable. To further prevent sequence effects, a randomized between-subject is used.

Procedure

Participants will first complete a questionnaire in which demographic data and previous experience with VR will be collected. They will then undergo one of the two conditions. To increase immersion, the participants choose one teammate from three visually similar-looking virtual agents. This is visualized in Figure 1. In the touch condition, their choice will be confirmed with a handshake. The quiz will be presented in a multiple-choice format with four answer options. During the quiz, participants can ask their virtual agent for advice, and the virtual agent will provide a random suggestion. Participants will be informed beforehand that the agent is not infallible and may not always provide the correct answers. In the touch condition, the respondent will be touched on the shoulder exactly three times. These touches are intended to be both notifying and motivating. After the VR interaction, participant will fill out questionnaires to measure trust, virtual body ownership and plausibility. There will be a short interview at the end to explore their personal experience in the situation. Additionally objective data will be recorded, such as the frequency of requests for help from the virtual agent. The VR environment during the quiz is visualized in Figure 2.

Changes to the Previous Study

A similar experiment was already conducted in a previous study. The qualitative results of that study led to the following changes in the existing study design. A longer priming phase will be implemented to give participants time to get used to wearing the haptic vest and to acclimate themselves in the VR environment. In addition, technical details of the VR environment, such as the size of the avatar and the placement of the virtual agent in the field of view, will be adjusted. The VR environment of the bar will be made smaller. At the beginning of the experiment, participants will be introduced by a moderator who explains the game principle and presents the quiz questions. There will also be other virtual agents present in the bar to make the scenario more plausible.

Timeline

Literature

• [1] Crusco, A. H., & Wetzel, C. G. (1984). The Midas touch: The effects of interpersonal touch on restaurant tipping. Personality and Social Psychology Bulletin, 10(4), 512-517.
• [2] Thielmann, I., & Hilbig, B. E. (2015). Trust: An integrative review from a person–situation perspective. Review of General Psychology, 19(3), 249-277.
• [3] Law, T., Malle, B. F., & Scheutz, M. (2021). A touching connection: how observing robotic touch can affect human trust in a robot. International Journal of Social Robotics, 13(8), 2003-2019.
• [4] Lin, J., Cronjé, J., Käthner, I., Pauli, P., & Latoschik, M. E. (2023). Measuring Interpersonal Trust towards Virtual Humans with a Virtual Maze Paradigm. IEEE Transactions on Visualization and Computer Graphics, 29(5), 2401-2411.
• [5] Evans, A. M., & Krueger, J. I. (2009). The psychology (and economics) of trust. Social and Personality Psychology Compass, 3(6), 1003-1017.
• [6] Andersen, P. A., & Leibowitz, K. (1978). The development and nature of the construct touch avoidance. Environmental psychology and nonverbal behavior, 3, 89-106.

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