Research Paper VRET (2018) MediaLAB Amsterdam, The Netherlands

VIRTUAL REALITY EXPOSURE (VRET)

Agnetha Mortensen Janina Saarnio Abstract MediaLAB Amsterdam, HvA University of Turku We sought to develop a virtual reality Wibautstraat 2-4, Amsterdam Finland (VRET) environment that is adaptable to the biofeedback of the user. Our prototype is built in Unity The Netherlands [email protected] and integrates the sensory data from Mio Link heart

[email protected] rate monitor transferring it through a computational

Yujie Shan model that individually adapts to the VR environment. Christiaan van Leeuwen Kyushu University, Our final concept is a user case located in an Hoegschool van Rotterdam Japan underwater VR environment focused on the specific The Netherlands [email protected] of sharks; galeophobia. Our research follows a [email protected] multidisciplinary approach, combining fields of design thinking, psychology, cognitive neuroscience, human- computer interaction (HCI) and affective computing.

Author Keywords Virtual reality; affective computing; exposure therapy; biofeedback; detection; sensor technology

ACM Classification Keywords H.5. Human-Centered Computing (e.g. HCC): Human- Permission to make digital or hard copies of part or all of this work for Computer Interaction (HCI) personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights Introduction for third-party components of this work must be honored. For all other We were assigned a task on how to track and uses, contact the Owner/Author. transform it to a Virtual Reality (VR) environment. Copyright is held by the owner/author(s). The ability of VR to simulate real-life situations that elicit similar subjective and physiological body reactions has made its way into psychological research [1]. The immersive nature of VR is seen capable of activating “real” emotions and therefore, it offers new possibilities

1

to easily investigate human behaviors in a controlled physiological responses from our body, it is highly environment. The premise of VRET is relying on possible that the self-reflection of the subject does not triggering the perceptual cues that activate our correlate with the “emotional” data. Due to this simple emotional experiences and create the sense of feeling fact, emotions appear and remain somehow unfamiliar in a VR environment - which we will from now on call as and unresolved for us. As Marvin Minsky [5] states, presence. We know high presence is especially crucial human emotions come under the category of ‘suitcase for emotional involvement during the initial phase of like’ definitions we use only to conceal “...the VRET to ensure the immersion of the user. [1] complexity of extensive ranges of different things whose relationships we do not yet comprehend.”. The opportunities of using virtual reality as a medium Therefore, it is only possible to make estimates of for exposure therapy has already been investigated. In emotions. contrast to in vivo exposure therapy, VRET provides some advantages, such as higher acceptance among Physiologically our emotions are seen to be processed patients, lower costs and higher accessibility [2]. Also, through a limbic system, which is situated behind the nowadays technology by itself is shown to create an neocortex part of our brain. The neocortex parts deal emotional presence that may become useful when with conscious thoughts and decision making. On the

designing mental health applications directly aiming to contrary, the very nature of the limbic system and our Figure 1; Generic model of modify problematic emotions. [1] emotions are illogical, irrational and unreasonable [6]. emotion detection. Our prototype follows a basic and the most common In cognitive neuroscience, emotions are strongly linked method of exposure therapy relying on “fear to our decision making as whenever exposed to a habituation” [3], but the individual biofeedback will particular stimulus we construct and store a somatic automatically control the steps of a graded exposure. marker between the stimulus and our affective state. We believe that our design based on triggering the Then these somatic markers are stored in our memory fearful stimulus up to a point before the activation of and later used for decision making in similar or maladaptive behavioral responses (i.e., avoidance or different context [7]. In fact, at the psychological level panicking) is an effective way to treat specific . emotions are regarded as tacit appraisals of different situations regarding personal goals, concerns or needs Emotions and Behavior [8].

Until today there is no universally accepted theory According to the emotion-focused therapy approach as about emotions. We decided to follow the famous well as having emotions we also live in a constant Russell’s circumplex model of affect (1980) that divides process of making sense of our emotions [9]. The all emotions into a two-scale diagram according to their dialectical-constructivist view of human functioning intensity of arousal and valence. Commonly, emotions helps to explain the process. The circular process of can be measured from physiological changes (i.e., making sense of experience is run through bodily-felt heart rate), behavioral responses (i.e., facial sensations connected to our awareness and memory expression) and/or cognitive interpretation (i.e., self- and later articulated in language. Therefore, emotions reporting) (see Figure 1) [8]. The most important in the are an adaptive form of information-processing and study of emotions is to use ROIs (regions of interests) action readiness that guides people in their interactions to extract information from our affective nature [4]. with other people and the surrounding environments However, even though we could be able to extract all [9].

2

philosophical point of view, the difference between fear Fear as an Emotion and lies in their relation to an object, as Sara Ahmed [12] states. According to Ahmed, fear has an Fear is defined as one of the basic emotions by object whereas anxiety has not. The temporal consensus [8, 10]. From a physiological perspective, dimension in fear only appears when we are affronted fear is sympathetic arousal and an aversive subjective to a threat. The fearful moment “projects us from the threat. Our sympathetic nervous system (SNS) is present into a future” which is felt as an intense bodily activated through the amygdala and involves experience of the present. Sweating, increased heart alterations in blood pressure (BP) that can be rate, and unpleasant intensity through the whole body physiologically measured from the changes in heart push us to either flight-freeze-or-fight. Ahmed rate or skin conductance, for example [11, 21]. concludes that we fear when an object approaches us

and we anticipate it to hurt us [12]. From an evolutionary point of view, negative emotions

are often useful and even necessary for our survival. In Practically this means that even though the amygdala is fact, anxiety, anger, and fear would not exist if they central to emotional learning and memory, it is not were not useful. However, the risk is that unpleasant critical to the expression and regulation of emotion. The emotions can turn dysfunctional when they also endure amygdala only serves as a “smoke detector”, pre- in the circumstances where they are not needed [9]. consciously interpreting whether the incoming sensory People who have a particular kind of phobia share a information is a threat or not [9]. Therefore, the standard feature of amygdala hyper-responsiveness activation of our conscious interpretation is needed to over the hippocampus and medial prefrontal cortex help us overwrite the maladaptive fear memories (see (mPFC) that are responsible for cognitive interpretation Figure 2). However, the change can only occur by first [13]. activating the emotional memory with a fearful stimulus

which we will simulate in VR. Relevant for our concept is that usually, people try to Figure 2; A basic model showing push down the unpleasant emotions such as pain, fear the link between the physical or anxiety. However, all of these so-called “escape Overcoming Fear through Exposure Therapy world relying on perceptual cues methods” will only cause harm in the long term. Exposure therapy has shown to be the most effective and their references to the Avoidance of emotion often creates a long-term feeling treatment for phobias. Most commonly it is practiced by different layers in our mental of suffering and prevents us to live life to its fullest [9]. using one of the two scientifically proven methods; world. In order, not to let the negative emotions take over flooding or graded-exposure. Research indicates that one’s actions and behavior one needs to be aware of, to gradual and prolonged exposure is the most optimal.

tolerate and to regulate negative emotionality as well Exposure therapy is rooted in classical conditioning as enjoy positive emotionality [14]. Scientifically we where every exposure trial starts by activating the often refer to this regarding emotion regulation or maladaptive experience and making the patients emotional intelligence. Emotional intelligence means contact with the feared, conditioned stimulus (CS). The that the individual can use emotions as a guide, instead condition is maintained until the anxiety is lowered of being a slave or a victim of emotions [22]. down. This process is often referred to as habituation and can only lead to successful outcomes if the patients The primary challenge of detecting fear is its close are prevented to avoid the phobic stimuli in their sight relation to anxiety and the oppression of our [15]. The traditional exposure therapy methodology parasympathetic nervous system. From the relies on the assumption that performance during

3

training and fear reduction within an exposure trial memory should be taken into account when designing (also referred to as within-session habituation WSH) is the exposure trial in VR. “commensurate with learning” [16]. Methods Exposure therapy can also follow a method of single To come up with our concept we used different massed exposure or a trial composed of multiple short research methods from the MediaLAB Amsterdam exposures. Some evidence supports a single massed Design Method Toolkit, such as a survey, in-depth exposure to be more efficient than a series of short interview and research collage together with our own exposures having the same total duration. Different methods and expert consultations. Along with the techniques of distraction during the exposure therapy insights we generated several good ideas and concepts, cause a disrupted exposure [16]. However, these finally resulting into a VRET concept with an underwater findings are not in line with some studies state that user case. However, the computational model is distraction during the exposure therapy may facilitate designed to adapt to an object so it can be easily the fear reduction [17, 18]. Therefore, more than trying applied to different types of specific phobias in different to generate one method for exposure therapy the fear contexts.

Figure 3; Overview of most creative methods used in our project throughout the different sprints

4

Fear / Phobia No. Total % Ppl.

A burglar breaking into 31 56,36% the house / sclerophobia

Spiders or scorpions / 28 50,91% arachnophobia

Making mistakes / 25 45,45% erratophobia

Bees (apiphobia) / 24 43,64% wasps (spheksophobia)

Looking foolish in front 24 43,64% of people / gelotophobia

Not being able to 24 43,64% breathe / asphyxiphobia

Deep water or ocean / 21 38,18% thalassophobia

Sharks / galeophobia 20 36,36%

Death or dying / 20 36,36% thanatophobia

Being alone / 15 27,27% monophobia

Dark spaces / 15 27,27% nyctophobia

Jellyfish / scyphophobia 8 14,55%

Table 1; Results from International and Dutch survey on closed questions about specific phobias and fears. Blue color are phobias Figure 4; Results from Online Survey with open questions about fear, phobia and anxiety that could be adapted to an underwater environment. Online Survey to be harder to interpret and categorized. The survey To learn more from a target audience that is not that was also translated into Dutch and shared on Facebook social or open about their problems we decided to do a through our profiles as well as in a variety of relevant survey together with a follow-up interview to get Facebook groups for young women. Results from the Schwartz values and guidelines for the design. We survey revealed some interesting insights on the most combined open phobia/anxiety questions [30] and common phobias among our target group. Based on closed phobia questions [31] to create an extensive our findings from the online survey as well as desktop survey. We also used open questions which showed up research we developed three unique concepts that

5

could be alternated in a VR environment. We found that until most people were done and then they had to almost none of the participants suffer from severe present their collage. forms of phobia or anxiety but almost all of them The central insight from this session was that most suffered from them in some amount. phobias revolve around a memory or situation. This entails that those phobias could not as easily be In-Depth Interviews and Collage Session triggered in a controlled environment because they are Based on the Schwartz values (2006) we conducted in- very individual experiences for each person. depth interviews with eight young women from 3 different countries in the hope of getting a better Developing our Target Group and our Personas understanding of our target group and how they relate From the beginning of the project, we all agreed that to fear. We saw some overall similarities with high we wanted to create something meaningful that would levels of ambitions, fear of judgment and/or not being help people. We discussed a lot back and forth about good enough and being left out of a social circle/being issues and problems the society is facing today. During alone. We also applied the Five Factor Model (FFM) into our desktop research, we came across several our question to get a better understanding of the young interesting news articles on how anxiety is on the rise women's gaming habits, and by doing this, we could among young women, especially in the westernized get scientifically correct and unambiguous answers. countries like the UK and the US, but also in Asian countries like Japan and South Korea. We wanted to The central insight from the in-depth interviews was understand better what exactly was troubling young that although the target audience differs in kind of girls and women, and wanted to create something that

phobia, age, origin, and intensity of the phobia, could help and prevent mental health issues that could gradually facing the phobia helps them to overcome potentially arise.

their fears. A few weeks later in the project, we learned that unknowingly and unwillingly this was the first We defined our target group to be young women moment that exposure therapy started to play a role in between the age of 15-25. Not only because of the the project. troublesome inner struggles some of them might face, but also because statistics do show that VR is more Fear Research Collage Session exciting and appealing to young people (tweens, teens,

To narrow down which phobias would be interesting to and Millennials) [33]. We also chose to keep a primary use for the first exposure therapy concepts, we wanted focus on women because they are more sensitive to to try the research collage method. This method from physiological changes towards fearful stimuli [32]. the Design Method Toolkit (MediaLAB Amsterdam) was Women are also twice as likely as men to experience Figure 5; The above personas are perfect for people to visually explain their phobias and different types of [19]. To narrow down our based on basic research about the situations and memories associated with them. concept we chose to focus on a specific phobia as this is phobias and assumptions about easier to treat, as well as most of the anxieties revolve personality and emotions. These We did the session with five people from MediaLAB around a particular situation strongly relying on a personas helped to take the target Amsterdam and one person whom we got in contact context-dependent memory, but specific phobias can audience into account when we set with via the survey we did. Pictures of different kind of be more generalized. up the experiments. phobias were cut out to match together on colored paper sheets, and we let people work on their sheet

6

Final Design Criteria Pre-Experiment on Fear and Colors 1. The design must be coherent to enhance the We conducted a small experimental pre-study on fear immersion for the user experience. and aura (colors) to develop our computational model. When the environment and the rules within the fictional The primary goal of this experiment was to test a world are coherent, it has a better chance of enhancing change in the heart rate when the users are exposed to the immersion and also the presence of the user in a something fearful in a virtual environment. We decided

VR environment [34,35]. to focus on HR as the monitors are less invasive for the users as well as it is more easily available and cheap 2. The computational model in the prototype must compared to other sensors on the market. The sensors be able to interpret individual biofeedback and tested in this experiment include Mio Link and Garmin adjust the VR environment accordingly. Forerunner 35. We aimed to test if Mio Link is accurate As biofeedback is individual, it is essential that the enough to be used in our concept in virtual reality computational model take this into account and adapts environment. The sub-goal of this experiment was to the experience according to different user’s needs. gain some insights about the surrounding colors around the user (which are different from the environment 3. The VR experience should help the users cope with their phobia/anxiety and not make it worse. Time (min) What Tools It is essential to keep in mind the theories in exposure therapy and be aware of the user’s anxiety levels. The 5 Introduction and Personal talk phobia or anxiety should be triggered to measure the instructions biofeedback, but avoid overexposing them as that could end up traumatizing them even more. 5 Pre-survey and consent The survey + pen form 4. The concept could give feedback to the user about their emotional state. 5-10 Baseline trial: Soothing movie/ We believe that self-awareness about one’s emotional Watching a calm video soothing experience state through visual feedback could help users overcome their fears easier. 10-20 Experiment session: Mio Link + RGB light Playing scary game to with remote + recording 5. The concept could benefit from music to get physiological data equipment enhance the immersive experience. Binaural sounds could be applied to calm the user 5 Post-survey The survey + pen before, during and after the exposure trial. Table 2; Fear and Color (AURA) Experiment Setup 6. The prototype would be easily transferable to different phobia and environments. Total: 35-45 minutes per person We want to make sure that the prototype applies to other user cases and are easily transferable to other they are supposed to feel immersed in) while they are phobias. exposed to something fearful. This is related to our idea of having an aura around the user in VRET.

7

We got a total amount of 12 people to participate in the focusing only on colors, the intensity of the lights can experiment, 4 males, and 8 females. However, the final show to be more beneficial and a safe solution for number of valid data we took into account for building visual stimuli towards users. The aura is not adapted the computational model is 10 (M=4, F=6) of 5 for both into our final prototype but could be taken into account control groups (darkness/colors). The age of the in future research, primarily as a feature to enhance participants was between 22-30 years old. the immersion of the user. The baseline trial and the experiment session was recorded using GoPro HERO4 as well as Canon 80D Auditory Beat Stimulation through Binaural Beats with live recording through EOS Utility on Apple Mac. With the growth of technology, music has become an increasingly important facet of a game. It is, therefore, We decided to base the computational model relying on necessary to understand how it does affect our the baseline and the self-reported fear level. The behavior, concentration and cognitive stimulation. benefits of using baseline as one variable are that it Music activates the whole brain, and the perception of takes into account the daily variations in the heart rate sound and its tones are processed through the auditory – such as stress, the amount of sleep and the intake of cortex which transfers information to the hippocampus. caffeine. We also acknowledged that the self-reported What moves us to get emotionally involved in a song or fear level should play a role in the computational a movie is controlled by the amygdala. The amygdala is model. Based on the pre-experiment we gained many also responsible when we feel fear, and it is where we Figure 6; The Limbic System. insights that we could implement into our final version store traumatic experiences. Music is a unique tool that Source: D.P. Lyle, MD (2013) of the computational model. can repair brain damage and help to return lost memories [23], it can also help learning processes

Final Prototype [24], as well as reduce stress levels and anxiety [25]. We sought to design a realistic and coherent underwater VR environment to enhance the immersion It was vital for us to take all these factors of music of the user. The phobic stimulus is following a graded perception and behavior change into consideration exposure methodology, and the gaze is programmed to when creating our VRET prototype. We wanted to make prevent the avoidance behavior of the user. use of music that could potentially reduce anxiety and lower one's stress levels. Several studies on binaural Visual Design beats show exciting results when it comes to improving To make the user aware of her own emotions we cognition and reducing anxiety. One study using alpha- designed an Aura that can be adapted to our concept of theta brainwave biofeedback as a relaxation therapy VRET. The colorful lights around the user could aim to showed promising results in treating anxiety among visualize their emotional state and depending on the alcohol addicts. The brainwave treatment appeared to design either working as a feature to enhance the counteract the increase in circulating beta-endorphin immersion or create an additional layer in the VR levels seen in the control group of alcoholics, making environment. the subjects less reluctant to fall back into abuse of alcohol [28]. However, research shows that colors are differently interpreted in every culture which potentially can create Binaural beats are created when two coherent sounds difficulties for the outcome of the design, but by with nearly similar frequencies are presented to each

8

ear respectively with stereo headphones, the brain Gaze Implementation integrates the two signals and produces a sensation of Gaze is the first form of input and is a primary form of a third sound called binaural beat (BB) [26]. Binaural- targeting within mixed reality. Gaze tells you where the beats signals (BBS’s) were first observed by the user is looking in the world and lets you determine their German scientists H.W. Dove in 1839. In its purest intent. In the real world, you'll typically look at an form BBS’s consists of two pure tones of a different object that you intend to interact with. This is the same pitch being presented to each ear [27]. Research on with the gaze. In our computational model, the gaze binaural beats also shows that we may enhance mood works as a tool for interactive feedback from fear states, lower anxiety levels and improve vigilance by stimuli towards the player. In such a sense, the player using auditory beat stimulation [29]. cannot avoid the fearful stimuli (phobia) that is exposed. By stimulating the brainwaves through binaural beats, we wanted to empower the users and make them more at ease, gradually lower their stress levels as well as making the users less anxious about the phobia we wanted to treat. We chose to track the baseline of the users in a relaxing state while listening to a piece of binaural beats generated from Water Droplets and Water passing through a musical pipe that was tuned to 396Hz solfeggio frequency. Users would listen to this track for 5 - 10 minutes before entering the VRET. Within the VRET we had a second piece of underwater binaural beats tuned to 417Hz. We found this track suitable for the underwater theme of the specific phobia of sharks. This level of frequency may also help to facilitating behavior change according to the clinical Dr. Joseph Puleo research during the 70’s.

Computational Model The computational model takes into account two individual variables: baseline of the heart rate BPM (x) and self-reported fear level (y). Baseline setting takes approximately 5 minutes before the exposure trial and uses standard deviation. The individual maximum heart rate to stop the fearful stimulus is calculated from the baseline (x) as follows:

HR max = x + ((- 3.217 · y) + 53.417)1 self-reported fear level and the heart rate changes when the users were asked to play a video game called Slenderman (2013) in a closed environment. 1 This is a first iteration of the computational model that was built upon our experiment data where we found a small correlation between the

9

Figure 7; Computational Model applied to Final Prototype

Conclusion complex design. To validate the measured arousal Undeniably, the nature of our emotions is involuntary level, we could design new techniques for self-reporting and unconscious, but the earlier view of seeing emotion and tracking behavioral responses of the users in VR. as post-cognitive is inadequate. Emotion can precede The interactive environment also allows creating new cognition, but more importantly, it plays a vital role in designs for the illusion of competence and self-efficacy the information processing [9]. Fear by itself is natural of the user that might help to enhance the successful and vital for our survival, but the over-activation of our outcome of VRET. fear learning and memory can generate anxieties that prevent us to live life to its fullest. The interactive and Future Work immersive virtual reality environment can trigger real Because of its sympathetic nature measuring fear emotions, and help to modify our emotional learning arousal from a heart rate might become problematic. and memory. Only four studies show that heart rate can be used as an indicator of physiological response during the initial Unfortunately, the more advanced technologies to track fear activation (IFA) [16]. This might be since heart the activity of amygdala (such as infrared thermal rate indeed is “influenced by a myriad of factors other imaging or EEG monitors) are not available on a global than sympathetic fear-based arousal”, and sometimes market nor yet compatible with VR headsets. In future, falls under the oppression of our parasympathetic more accurate measurements will enable better nervous system. estimates of the user’s emotions with a cost of a more

10

As the healthy heart is not a metronome but a stimulating their brainwaves over a long enough time, “mathematical chaos” [20] heart rate variability (HRV) we could hopefully lower anxiety levels in patients and indicating the changes of time between interbeat change their behavioral responses towards their intervals might offer a better solution instead of the phobia. We also imagine connecting the binaural music traditional BPMs recording. HRV is an index of to colors that would represent the aura of the patients neurocardiac function which is affected continuously by and give visual feedback to patients about their heart-brain interaction and the processes of our emotional state and fear/anxiety level. autonomic nervous system (ANS) [20]. HRV has been widely used as an indicator of stress since the 1960s. Acknowledgments During the past two decades, various studies have shown its potential to indicate the individual capacity of We want to give big thanks to the MediaLAB emotion regulation [14]. Amsterdam and Amsterdam University of Applied Sciences for facilitating us with any necessary tools As HRV, also our emotions are forced to continually needed for this project. Special thanks to our coach change the environmental conditions reflecting “the Tamara Pinos Cisneros who guided us through from status of one’s ongoing adjustment to constantly sprint to sprint. We also want to thank Triple for changing environmental demands” [14]. By measuring assigning us to a very challenging problem that helped the resting HRV, we can predict the flexible, dynamic us growing and learning as individuals as well as in a regulation of autonomic activity. Higher HRV signals team. We also want to thank Radboud University “the availability of context- and goal-based control of GEMH-LAB and Behavioral Research Department for the emotions” whereas lower HRV can be linked to some personal feedback on our project that guided us in the degree of ‘laziness’ in the emotion regulation system right way of our final prototype. We also want to thank [13]. Therefore, measuring HRV during the baseline our fellow collaborators and creators at Kyushu trial might even predict the outcome of VRET. University for all their guidance and feedback throughout this project. Thank you so much to Danny What needs to be taken into account for the Dorstijn, our lead programmer, for cracking the code computational model is that even though heart rate and hacking the Mio Link device so we could connect it does not necessarily decline across the occasions of directly with Unity and get live data from the exposure the self-reported fear level does. As studies biofeedback in the VRET. Much thanks to everybody [3] show, declines in heart rate or skin conductance are else who helped us in one way or another and much not necessary for overall improvement. Therefore, and love to our colleagues at MediaLAB Amsterdam. most importantly, the successful exposure therapy should be mediated mainly in the cognitive shifts if not References directly in physiological changes [16]. We could 1. Peperkorn, Henrik M., Diemer, Julia, and Mühlberger, highlight the importance of fear toleration instead of a Andreas. 2015. Temporal dynamics in the relation between presence and fear in virtual reality. Computers in Human Behavior, fear reduction as an indicator of successful exposure 48 (July 2015) 542-547. DOI: therapy and take it into account in future research. https://doi.org/10.1016/j.chb.2015.02.028

When it comes to the binaural music implementation 2. Garcia-Palacios, A., Botella, C., Hoffman, H., and Fabregat, S. 2007. Comparing Acceptance and Refusal Rates of we could optimally get the users baseline by having Virtual Reality Exposure vs. In Vivo Exposure by Patients with them in relaxation therapy for 15 - 30 minutes as done Specific Phobias. CyberPsychology & Behavior, 10(5). in the Penistion and Kulkosky study [28]. By DOI: https://doi.org/10.1089/cpb.2007.9962

11

Biobehavioral Reviews. 36: 747-756 DOI: 3. Lang, Ariel J., and Craske, Michelle G. 2000 https://doi.org/10.1016/j.neubiorev.2011.11.009 Manipulations of exposure-based therapy to reduce return of fear: A replication. Behaviour Research & therapy 38 (2000): 1-12. DOI: 14. Frijda, Nico H. 1986. The Emotions. Cambridge University https://doi.org/10.1016/S0005-7967(99)00031-5 Press. ISBN-10: 0521316006

4. Cardone, Daniela, and Merla, Arcangelo. 2017. New 15. Ougrin, Dennis. 2011. Efficacy of exposure versus Frontiers for Applications of Thermal Infrared Imaging Devices: cognitive therapy in anxiety disorders: systematic review and Computational Psychophysiology in the Neurosciences. Sensors, meta-analysis. BMC Physiatry, 11:200. DOI: 17(5), 1042; DOI: 10.3390/s17051042 https://doi.org/10.1186/1471-244X-11-200

5. Minsky, Marvin. 2006. The Emotion Machine. 16. Craske, Michelle G., Kricanski, Katharina, Zelikowsky, Commonsense Thinking, Artificial Intelligence, and the Future of Moriel, Mystkowski, Jayson, Chowdhury, Najwa and Baker, Aaron. Human Mind. Simon & Schuster, NY. 2008. Optimizing inhibitory learning during exposure therapy. Behaviour Research and Therapy, 46: 5-27. DOI: 6. Freeman, Walter J. 1998. Emotion is essential to all https://doi.org/10.1016/j.brat.2007.10.003 intentional behaviors. Chapter 8 in Emotion, Development, and Self-Organization Dynamic Systems Approaches to Emotional 17. McNally, Richard J. 2007. Mechanism of exposure Development. Cambridge University Press. pp. 209-235. DOI: therapy: How neuroscience can improve physiological treatments https://doi.org/10.1017/CBO9780511527883.010 for anxiety disorders. Clinical Psychology Review, 26(6): 750-759. DOI: https://doi.org/10.1016/j.cpr.2007.01.003 7. Yannakakis, Georgios N., Cowie, Roddy, and Busso, Carlos. 2017. The Ordinal Nature of Emotions. Seventh 18. Johnstone, Kristy A., and Page, Andrew C. 2004. International Conference on Affective Computing and Intelligent Attention to phobic stimuli during exposure: The effect of Interaction (ACII). distraction on anxiety reduction, self-efficacy and perceived control. Behaviour Research and Therapy, 42:249−275. DOI: 8. Ekman, Paul, and Davidson, Richard J. 1994. The nature https://doi.org/10.1016/S0005-7967(03)00137-2 of emotion. Fundamental Questions. Oxford University Press. ISBN: 9780195089448 19. Remes, Olivia, Brayne, Carol, Linde van der, Rianne, and Lafortune, Louise. 2016. A systematic review of reviews on the 9. Greenberg, L.S. 2004. Emotion-focused therapy. Clinical prevalence of anxiety disorders in adult populations. Brain and Psychology and . 11:3-16. Behavior, 6(7). DOI: http://doi.org/10.1002/brb3.497

10. Plutchik, R. 1980. A general psychoevolutionary theory of 20. Shaffer, Fred, and Ginsberg, J. P. 2017. An overview of emotion. In R. Plutchik and H. Kellerman (Eds.) Emotion: Theory, heart rate variability metrics and norms. Frontiers in Public Health, research, and experience: Vol. 1. Theories of emotion (pp. 3-33). 5, 258. DOI: http://doi.org/10.3389/fpubh.2017.00258 New York: Academic. 21. Nasoz, Fatma, Alvarez, Kaye, Lisetti, Christene L., and 11. Hsu, Y-C., Yu, Lung, Chen, H., Lee, H-L., Kuo, Y-M., and Finkelstein, Neal. 2003. Emotion recognition from physiological Jen, Chauying J. 2012. Blood Pressure Variations Real-Time Reflect signals for presence technologies. International Journal of the Conditioned Fear Learning and Memory. PLoS ONE 7(4). DOI: Cognition, Technology and Work – Special Issue on Presence, 6(4). https://doi.org/10.1371/journal.pone.0032855 DOI: https://doi.org/10.1007/s10111-003-0143-x

12. Ahmed Sara. 2014. The Cultural Politics of Emotion. 22. Kappas, Arvid. 2013. Social regulation of emotion: messy Routledge. ISBN 0415972558. layers. Frontiers of Psychology. 15 February. DOI: https://doi.org/10.3389/fpsyg.2013.00051 13. Thayer, Julian F., Ahs, Frederik, Fredrikson, Mats, Sollers III John J. and Wager, Tor D. 2012. A meta-analysis of heart rate 23. Simmons-Stern, Nicholas R., Budson, Andrew E., and variability and neuroimaging studies: Implications for heart rate Ally, Brandon A. 2010. Music as a Memory Enhancer in Patients variability as a marker of stress and health. Neuroscience and with Alzheimer’s Disease. Neuropsychologia, 48(10), 3164–3167.

12

DOI: http://doi.org/10.1016/j.neuropsychologia.2010.04.033 33. Burch, Aaron. January, 2016. VR and Consumer Sentiment. Touchstone VR, Touchstone Research - Innovation and 24. Overy, Katie. 2000. Dyslexia, Temporal Processing and Excellence. Music: The Potential of Music as an Early Learning Aid for Dyslexic Children. Psychology of Music, 28(2), 218-229. DOI: 34. Cheng, Keving and Cairns, Paul A. 2005. Behavior, https://doi.org/10.1177/0305735600282010 Realism and Immersion in Games. University College London, Interaction Centre London, United Kingdom. Copyright: CHI, April 2 25. Jimenes-Jimenez, Maria, Garcia-Escalona, Alma, Martin- – 7, 2005. Portland, Oregon, USA. Lopez, Alejandra, De Vara-Vara, Raquel, and De Haro, Joaquin. 2013. Intraoperative stress and anxiety reduction with music 35. Mestre, Daniel R. 2008. Immersion and Presence, therapy: A controlled randomized clinical trial of efficacy and safety. Movement and Perception, CNRS & University of the Mediterranean. Journal of Vascular Nursing, 31(3):101-106. DOI: Marseille, France. https://doi.org/10.1016/j.jvn.2012.10.002

26. Xiang, Gao, Hongbao, Cao, Dong, Ming, Hongzhi, Qi, Xuemin, Wang, Xiaolu, Wang, Runge, Chen, and Peng, Zhou. 2014. Analysis of EEG activity in response to binaural beats with different frequencies. International Journal of Psychophysiology, 94(3), 399- 406. DOI: https://doi.org/10.1016/j.ijpsycho.2014.10.010

27. Richard, Cauley K. 2013. An Empirical Investigation Into the Effect of Beta Frequency Binaural-beat Audio Signals on Four Measures of Human Memory. Hemi Sync. https://hemi- sync.com/research-papers/an-empirical-investigation-into-the- effect-of-beta-frequency-binaural-beat-audio-signals-on-four- measures-of-human-memory/

28. Peniston, Eugene, and Kulkosky, Paul J. 1989. α-θ Brainwave Training and β-Endorphin Levels in Alcoholics. Alcoholism: Clinical and Experimental Research, 13: 271–279. DOI: https://doi.org/10.1111/j.1530-0277.1989.tb00325.x

29. Chaieb, Leila, Wilpert, Elke C., Reber, Thomas P., and Fell, Juergen. 2015. Auditory Beat Stimulation and its Effects on Cognition and Mood States. Frontiers in Psychiatry, 6:70. DOI: https://doi.org/10.3389/fpsyt.2015.00070

30. Marks, I.M., and Mathews, A.M., 1979. Brief standard self-rating for phobic patients. Behaviour research and therapy, 17(3), 263-267. DOI: https://doi.org/10.1016/0005- 7967(79)90041-X

31. Ollendick, T.H. 1983. Reliability and validity of the revised fear survey schedule for children (FSSC-R). Behaviour research and therapy, 21(6), 685-692. DOI: https://doi.org/10.1016/0005-7967(83)90087-6

32. Kring, A.M. and Gordon, A.H., 1998. Sex differences in emotion: expression, experience, and physiology. Journal of personality and social psychology, 74(3), p.686.

13