Investigating Travel Techniques for a Context Conditioning Experiment in Virtual Reality

Closed Human-Computer Interaction Bachelor Thesis No Affiliation

Investigating Travel Techniques for a Context Conditioning Experiment in VirtualReality

Motivation/Goals

The interest of this thesis is to investigate which Virtual Reality (VR) travel technique could benefit the Context Conditioning (CC) experiment paradigm of the company VTplus GmbH - virtual therapy + research systems (VT+) most. The paradigm is used by various therapy research clients, e.g. PROTECT-AD (2015-2019). Currently used travel techniques - for controlled experimental studies as base for exposure-exercises - are passive driven teleportation by the experimenter and steering by joypad. Previous work in the field of locomotion has indicated that both of them come with certain drawbacks. Steering is known to induce simulator sickness (Weißker, Kunert, Frohlich, & Kulik, 2018) while teleportation beyond the visible space can impact the spacial awareness (Montello, 1993). In the last years a huge variety of different travel techniques gained popularity, some of them especially created for VR-usage. Therefore the question arose which one would be the most fitting, especially for the CC–VR-paradigm and forthcoming simulations like exposure-exercises.

The CC experiment consists of three phases (exploration, acquisition and extinction)where in each phase you get presented two rooms from various angles. During the acquisition phase an aversive Unconditioned Stimulus (US) scream is presented several times in one of the two rooms. Thereby the room Neutral Stimulus (NS) (context), where the aversive US was presented, becomes the Conditioned Stimulus (CS). The user should show an aversion, a Conditioned Reaction (CR) towards theroom from this point. The concept is explained in more detail further below in the appendix.

Requirements

The requirements for the new travel technique are as following:

Requirement 1. (R1) Variables which are queried during the CC-Experiment by default, valence, arousal, anxiety and contingency towards the conditioned room and therefore the CR should be equal or show stronger values with the same direction(pos/neg) using the new travel technique.

Requirement 2. (R2) The spacial awareness should increase compared to the current method.

Requirement 3. (R3) The user must not feel a large amount of simulator sickness

Requirement 4. (R4) The technique should be easy to use and should not require a high cognitive workload to operate

Requirement 5. (R5) The method should not require the development of any new hardware but utilize a default VR setup, e.g. a Head-Mounted Display (HMD) (e.g. HTC-Vive) with matching motion controllers or a joypad.

The goal is to elaborate fitting techniques, implement them inside the Unreal Engine 4 (UE4) and carry out a study to evaluate them. The chosen traveling techniques for this thesis will be selected after theoretical research and informal and formal testing. They will be compared to the current travel technique which is teleportation controlled by the experimenter.

References/Previous Work

There are many travel techniques utilized for VR and over the years, almost as many ways of classifying these techniques emerged. The main differentiation is made between walking, steering, selection- and manipulation-based traveling metaphors.

For example, Costas Boletsis stated in his literature review “The New Era of Virtual Reality Locomotion A Systematic Literature Review of Techniques and a Proposed Typology” (Boletsis, 2017) classification categories where the methods are divided into interaction type, VR motion type and VR interaction space. Where modalities of these categories are used to describe a travel technique.

Other techniques of classifying different travel methods are based on the distinction of subtasks (Bowman, Koller, & Hodges, 1998) or focus on user control (Bowman, Davis, Hodges, & Badre, 1999). Recently a promising way of classifying teleportation techniques was proposed by Weißker et al. (2018), see 2.1, where it is distinguished based on how the different stages of teleportation are implemented.

Four stages of the teleportation process with common options for their implementation. (target specification -> pre-travel information -> transition -> post-travel feedback) by Weißker et al. (2018)

The application where the travel technique will be used is for therapeutic exercises and experiments where controlled conditions are important. As stated in the Requirements, it’s important that the users don’t get distracted from the task by needing to focus on the travel technique or are experiencing symptoms of simulator sickness.

Continuing using passive teleportation or steering would be one of the most intuitive approaches to consider, but studies show that the visible motion during steering, contradicting motion cues of the vestibular system, is one of the aspects that induce simulator sickness, to which only those without a functioning vestibular system are fully immune (Lackner, 2014). Immediately teleporting the player to the points of interest avoids these mismatches in the sensory system but is a very artificial method of traveling and can impact the spacial awareness negatively, especially if the target is located beyond the visita space (Montello, 1993).

An alternative to these two well known approaches is jumping, user controlled tele-portation restricted to the vista space which could be therefore seen as an intermediate technique between the two. As Weißker et al. (2018) discovered during their study, jumping induced significantly less simulator sickness symptoms than steering. The disadvantage regarding spatial orientation induced by teleporting outside of the vista space could also vanish.

Seen from a current point of view, jumping is the most viable approach to consider. The only important drawback to jumping is most users clear preference for steering (Weißker et al., 2018) in comparison to jumping for the use case of freely exploring unknown virtual environments. Since the users preference to steering and the technological advantage jumping offers, a hybrid would be imaginable. Controller based movement, but not using infinitely small steps that convey a movement but noticeable increments in the viewed direction if the user-input equals forward.

Contradicting to Weißker et al. (2018) a smaller study by Bozgeyikli, Raij, Katkoori, and Dubey (2019) where different roomscale travel techniques were compared indicated even a user preference for Point & teleport (Jumping) which also received better scores in all criteria queried than the other seven compared methods.

Method

The approach to identify the most fitting traveling method is to do further research on related work in the field. Considering their results, the next step would be to implement different traveling techniques inside the game engine and evaluate them with a formal and informal testing procedure. The most promising methods will be used in a study where users must complete the CC-experiment, including questionnaires as well as additional questionnaires regarding the travel technique and pre-experience. Based on the results queried throughout the study, the techniques can be compared by means of variables, all measured variables are stated below in the section Variables.

The theoretically most promising option at this time would be a jumping implementation which realises the different phases according to Weißker et al. (2018) as follows:

1. Target Specification: The travel destination is selected using a parabolic targeting arc which starting point is the controller and the Endpoint marks the destination.

2. Pre-Travel Information: The endpoint of the arc defines the position and a glowing ring indicates the new position where the user will be teleported to. The rotation is indicated via an arrow which either keeps and shows the current orientation using the relative HMD-rotation or can be manually defined by user input.

3. Transition: During this phase the HMD monitors fade to black at the old position and fade in at the new position after the teleportation has occured.

4. Post-Travel Feedback: After the Transition is finished and the user is at the new position, the previous position is indicated by a small marker or a line going towards it.

The final method compared to the current technique is subject to change and may vary throughout the process.

Schedule

Planned schedule

Hypotheses

H1: The CR towards the room is stronger with the new travel technique than the current method. (R1)

H2: The new travel technique leads to better spatial awareness than the current method. (R2)

H3: The amount of simulator sickness does not increase using the new travel technique compared to the current method. (R3)

H4: The new travel technique induces an equal cognitive workload compared to the current method. (R4)

H5: The new travel technique results in a greater presence compared to the current method (R1/R2)

Variables

Independent Variable:

• Travel Technique

Dependet Variables:

• Presence (IPQ)
• Spatial Awareness (Multiple-Choice: Select correct Minimap)
• Simulator Sickness (SSQ)
• Cognitive Workload (NASA TLX)
• ContextConditioning Values (Valence, Arousal, Anxiety, Contingency, SAM, STAI)

Further:

• Demography Questionnaire

Study Design

Planned Study Design

Questionnaires

• Simulator Sickness Questionnaire (SSQ) (Kennedy, Lane, Berbaum, & Lilienthal, 1993)
• Igroup Presence Questionnaire (IPQ) (Schubert, Friedmann, & Regenbrecht, 1999)
• NASA-Task Load indeX (NASA TLX) (Hart & Staveland, 1988)
• State Trait Anxiety Inventory (STAI) (Laux, Glanzmann, Schaffner, & Spielberger, 1981)
• Self Assessment Manikin (SAM) (Bradley & Lang, 1994)

References

Boletsis, C. (2017). The new era of virtual reality locomotion: A systematic literature review of techniques and a proposed typology. Multimodal Technologies and Interaction, 1(4), 24.

Bowman, D. A., Davis, E. T., Hodges, L. F., & Badre, A. N. (1999). Maintaining spatial orientation during travel in an immersive virtual environment. Presence, 8 (6), 618–631.

Bowman, D. A., Koller, D., & Hodges, L. F. (1998). A methodology for the evaluation of travel techniques for immersive virtual environments. Virtual reality, 3 (2), 120–131.

Bozgeyikli, E., Raij, A., Katkoori, S., & Dubey, R. (2019). Locomotion in virtual reality for room scale tracked areas. International Journal of Human-Computer Studies, 122, 38–49.

Bradley, M. M. & Lang, P. J. (1994). Measuring emotion: The self-assessment manikin and the semantic differential. Journal of behavior therapy and experimental psychiatry, 25 (1), 49–59.

Hart, S. G. & Staveland, L. E. (1988). Development of nasa-tlx (task load index): Results of empirical and theoretical research. In P. A. Hancock & N. Meshkati(Eds.), Human mental workload (pp. 139–183). Amsterdam: Elsevier Science Publishers B.V.

Kennedy, R. S., Lane, N. E., Berbaum, K. S., & Lilienthal, M. G. (1993). Simulator sickness questionnaire: An enhanced method for quantifying simulator sickness. The International Journal of Aviation Psychology, 3 (3), 203–220. eprint: https://doi.org/10.1207/s15327108ijap0303_3

Lackner, J. R. (2014). Motion sickness: More than nausea and vomiting. Experimental brain research, 232 (8), 2493–2510.

Laux, L., Glanzmann, P., Schaffner, P., & Spielberger, C. D. (1981). Das state-trait-angstinventar (stai): Theoretische grundlagen und handanweisung. Weinheim: Beltz Test GmbH.

Montello, D. R. (1993). Scale and multiple psychologies of space. In European conference on spatial information theory (pp. 312–321). Springer.

PROTECT-AD. (2015-2019). Bmbf - fkz: 01ee1402a, leitung: Wittchen, h.-u. Retrieved December 18, 2018, from http://psylux.psych.tu-dresden.de/i2/klinische/Studien/protect/index2.html

Schubert, T., Friedmann, F., & Regenbrecht, H. (1999). Embodied presence in virtual environments. In R. Paton & I. Neilson (Eds.), Visual representations and interpretations (pp. 269–278). London: Springer London.

Weißker, T., Kunert, A., Frohlich, B., & Kulik, A. (2018). Spatial updating and simulator sickness during steering and jumping in immersive virtual environments. In 2018 ieee conference on virtual reality and 3d user interfaces (vr) (pp. 97–104). IEEE.

Appendix

Context Conditioning

Contextual (fear) conditioning occurs when a user, placed in a new environment (NS), is presented with an aversive US and then is removed from that environment. If the user has learned the association between the environment and the aversive US, the user will show a negative association, CR, upon returning to the same environment.

For the company’s context conditioning paradigm simulation, the user has to associate the NS (room/environment) with an aversive US (scream 95db) so that if they are presented with the now CS (room/environment) again, without the aversive US, they show a CR (anxiety) due to the association with the aversive stimulus.

A CC experiment can be split up into three phases. In the first phase, the Exploration-phase, participants get the chance to explore the different contexts. In VT+’s there are two contexts, namely two different office rooms. After the initial exploration phase, follows the Acquisition-phase. Here the association of the context with the aversive US is created. Participants again visit the two rooms. However, this time the aversive US is presented in one of those two rooms. In the final phase, the Extinction-phase, the two contexts are presented again, without the aversive US.

After each phase, participants have to rate the two rooms on valence, arousal and anxiety. Furthermore, after phase two and three, they also rate how likely it is to hear the aversive US in the room (contingency rating)

Context Conditioning Procedure

Supervision of the study by the company VTplus

VT+ develops and distributes virtual reality simulation systems to carry out behavioural exercises and empirical research in the fields of psychotherapy, psychiatry, psychosomatics, neurology and pharmacological effectiveness as well as security research.

VT+ supervised several mandatory internships of the study programmes of the University of Würzburg and the University of Applied Sciences Würzburg-Schweinfurt, as well as bachelor theses. This project is supervised by Bastian Lange and Mathias Müller at VT+.

This project is supervised by Bastian Lange and Mathias Müller at VT+.

Contact Persons at the University Würzburg