Blog Archives

To see or not to see: A brief look at hallucinations in virtual reality applications

As a teenager I was fascinated with LSD purely as a consequence of my love of The Beatles and its alleged association with songs such as ‘Lucy in the Sky with Diamonds‘ (I say ‘alleged’ because all Beatle fanatics know that this song got its’ title from a drawing by John Lennon’s son Julian and that lyrically the song was inspired by the writings of Lewis Carroll, the creator of Alice in Wonderland [AIW], a book which gave its’ name to AIW Syndrome that I examined in a couple of previous blogs).

When I first started teaching my ‘Addictive Behaviours’ module back in 1990, almost all my lectures concentrated on drug addictions (as opposed to behavioural addictions which now take centre stage in my teaching), and it was my session on hallucinogenic drugs (also known as psychedelic drugs) that was always the most fun to teach and the topic that students appeared to be most engaged in. Like many of my students, I have always been interested in altered states of consciousness both in my own research into addiction and the topic more generally.

1jLwYlJBDyzH2qO1aGvCfLQ

The reason why I mention all these things as that I did a media interview on the hallucinogenic effects of virtual reality products. The interview was based on comments by Microsoft researcher Mar Gonzalez Franco, who said that virtual reality will soon replace the need for hallucinogenic drugs. More specifically, she was quoted as saying:

“By 2027 we will have ubiquitous virtual reality systems that will provide such rich multi-sensorial experiences that will be capable of producing hallucinations which blend or alter perceived reality. Using this technology, humans will retrain, recalibrate and improve their perceptual systems…In contrast to current virtual reality systems that only stimulate visual and auditory senses, in the future the experience will expand to other sensory modalities including tactile with haptic devices“.

Claims that VR products have the potential to induce hallucinogenic experiences have already started appearing in the media. A recent story in the Daily Mail reported that there was already a VR app (SelfSound) that claimed it can reproduce the effects of hallucinogenic drugs and plays on the neurological phenomena known as synaesthesia and that a “program is used to promote mediation through creating abstract reality [and] plays face-melting music with synesthetic DMT-style visualizations uniquely generated in response to [a person’s] voice”. (DMT is an abbreviation for dimethyltryptamine, a powerful hallucinogenic drug).

Over the last seven years, I have published a series of studies with Dr. Angelica Ortiz de Gotari (some of them listed in the ‘Further reading’ section below) showing that hallucinations are common among video gamers in our working examining Game Transfer Phenomena (GTP). Therefore, it’s no surprise that VR games can do the same thing. We have reported that visual and auditory hallucinations are commonly experiences by regular videogame players.

For instance, one of our studies published in the International Journal of Human-Computer Interaction found that some video gamers experience altered visual perceptions after playing (e.g., distorted versions of real world surroundings). Others saw video game images and misinterpreted real life objects after they had stopped playing. Gamers reported seeing video game menus popping up in front their eyes when they were in a conversation, or saw coloured images and ‘heads up’ displays when driving on the motorway. Our study analysed 656 experiences from 483 gamers collected in 54 online video game forums. Visual illusions can easily trick the brain, and staring at visual stimuli can cause ‘after-images’ or ‘ghost images’ among videogame players. We found that GTP were triggered by associations between video game experiences, and objects and activities in real life contexts. Our findings also raised questions about the effects of the exposure to specific visual effects used in video games.

We also reported that in some playing experiences, video game images appeared without awareness and control of the gamers, and in some cases, the images were uncomfortable, especially when gamers could not sleep or concentrate on something else. These experiences also resulted in irrational thoughts such as gamers questioning their own mental health, getting embarrassed or performing impulsive behaviours in social contexts. However, other gamers clearly thought that these experiences were fun and some even tried to induce them.

Visual experiences identified in GTP show us the interplay of physiological, perceptual and cognitive mechanisms and the potential of learning with video games even without awareness. It also invites us to reflect about the effects of prolonged exposure to synthetic stimuli and the challenges that the human mind affront due to the technological advances that are still to come. However, because we collected our data for most of our published studies from online video game forums, the psychological profile of the gamers in our studies are unknown. However, different gamers reported similar experiences in the same games. This highlights the relevance of the video games’ structural characteristics but gamers’ habits also appear to be crucial. Some gamers may be more susceptible than others to experience GTP. The effects of these experiences appear to be short-lived, but some gamers experience them recurrently. It goes without saying (but I’ll say it anyway) that more research is needed to understand the cognitive and psychological implications of GTP. Most of these GTP experiences are viewed positively but a small minority of players find them detrimental.

Whether such hallucinations – either in typical videogames or VR videogames – can be induced on demand is debatable. Very few players in our own research said they were able to induce hallucinations. At present, we simply don’t know what the long-term effects of VR gaming will be and that goes for VR-induced gaming hallucinations too. It may be the case that VR induced hallucinogenic states will be ‘safer’ than ones induced by psychedelic drugs as there is no ingestion of a psychoactive substance, but that’s just speculation on my part.

Dr. Mark Griffiths, Professor of Behavioural Addiction, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

Cawley, C. (2016). Virtual Reality could make you hallucinate; Don’t freak out. Tech Co, December 15. Located at: http://tech.co/virtual-reality-hallucinate-dont-freak-2016-12

Hamill, J. (2016). Windows of perception: Microsoft says virtual reality will soon have same mind-bending effects as LSD. The Sun, December 7. Located at: https://www.thesun.co.uk/news/2347705/microsoft-says-virtual-reality-will-soon-have-same-mind-bending-effects-as-lsd/

Liberatore, S. (2016). That’s trippy! Watch the VR app that claims to be able to reproduce the effects of a hallucinogenic drug. Daily Mail, May 4, Located at: http://www.dailymail.co.uk/sciencetech/article-3572184/That-s-trippy-Watch-VR-app-claims-able-reproduce-effects-hallucinogenic-drug.html

Ortiz de Gortari, A.B. & Griffiths, M.D. (2012). An introduction to Game Transfer Phenomena in video game playing. In J. Gackenbach (Ed.), Video Game Play and Consciousness (pp.223-250). Hauppauge, NY: Nova Science.

Ortiz de Gortari, A.B. & Griffiths, M.D. (2014). Altered visual perception in Game Transfer Phenomena: An empirical self-report study. International Journal of Human-Computer Interaction, 30, 95-105.

Ortiz de Gortari, A.B. & Griffiths, M.D. (2014). Auditory experiences in Game Transfer Phenomena: An empirical self-report study. International Journal of Cyber Behavior, Psychology and Learning, 4(1), 59-75.

Ortiz de Gortari, A.B. & Griffiths, M.D. (2014). Automatic mental processes, automatic actions and behaviours in Game Transfer Phenomena: An empirical self-report study using online forum data. International Journal of Mental Health and Addiction, 12, 432-452.

Ortiz de Gortari, A.B. & Griffiths, M.D. (2015). Game Transfer Phenomena and its associated factors: An exploratory empirical online survey study. Computers in Human Behavior, 51, 195-202.

Ortiz de Gortari, A.B. & Griffiths, M.D. (2015). Auditory experiences in Game Transfer Phenomena: An empirical self-report study. In: Gamification: Concepts, Methodologies, Tools, and Applications (pp.1329-1345). Pennsylvania: IGI Global.

Ortiz de Gortari, A.B. & Griffiths, M.D. (2016). Prevalence and characteristics of Game Transfer Phenomena: A descriptive survey study. International Journal of Human-Computer Interaction, 32, 470-480.

Ortiz de Gortari, A.B., Pontes, H.M. & Griffiths, M.D. (2015). The Game Transfer Phenomena Scale: An instrument for investigating the non-volitional effects of video game playing. Cyberpsychology, Behavior and Social Networking, 18, 588-594.

Rothman, P. (2014). Virtual Reality and Drugs – Yes, you should get high before using VR. H Plus Magazine, July 31. Located at: http://hplusmagazine.com/2014/07/31/virtual-reality-and-drugs-yes-you-should-get-high-before-using-vr/

Gore-ist information: A brief look at virtual reality horror games

“I recently played ‘The Visitor’ in VR. In front of an audience of drunken friends egging on my high pitch outbursts. I lasted seven out of the ten minutes, finally succumbing after a close encounter with a pixelated pillow. The Visitor’s story is about an unexpected guest calling to your house in the middle of the night. Developed by ‘NostalgicBear VR’ for the ‘Oculus Rift’ and ‘HTC Vive’ it relies on atmosphere to unsettle players, using visual cues in the form of intermittent flickering lights to inform the player where to look. Paralysed and lying in bed, you can only wait and watch as the strange occurrences culminate in one of the biggest jump scares I’ve ever experienced. As virtual reality goes, this particular experience has a high creep factor. It’s one of those new VR ‘games’ that really should come with a free pair of pants…In the wake of the PlayStation VR release, headed up by the dark and psychological Here They Lie, pretty much every major gaming outlet slashed their prices on horror games and gamers all over the world have been celebrating Halloween with their first exposure to a virtual reality freak out…VR grips the gamer with such a suspension of disbelief; when the headset is on there is seemingly no escape. Do developers take into account the psychological differences between previous gaming horror experiences and that of VR?”

The opening quote in today’s blog is from an article by Gareth May published last month for the Wareable website (‘Could VR horror be too…horrifying?’). I was interviewed by May for the story and is one of a number of media stories that I have been interviewed over the last year concerning virtual reality. Regular readers of my blog will know that I have a personal interest in horror films and a professional interest in excessive use of virtual reality so it was an interview I enjoyed doing (in fact, May interviewed me for two stories simultaneously, the other being on mechanophilia – sexual arousal from machines – which also was published last month in an article in the Daily Telegraph).

In his article on VR horror, May wanted to know about whether the playing of VR horror games could be problematic in any way (or as May asked me, ‘Is it possible that VR is just a bit too ‘real’?’). I pointed out that there had been little empirical research on the topic and that almost everything that I said was speculative. I noted that while VR is certainly more immersive than usual, we should remember that immersion can occur even without being in an VR environment. For instance, a lot of my research into video gaming demonstrates that gaming can be immersive (particularly the research I have been carrying out with Dr. Angelica Ortiz de Gortari on game transfer phenomena and some research I co-authored in the mid-2000s on time loss in video game play). I did point out to May that for most people, there’s not going to be a problem with playing VR horror games. Those that already enjoy watching horror films, the vast majority will probably love it even more in VR and it’s not going to have a negative impact on them. I told May that I loved gore in horror films and said that I would probably be fine playing an immersive horror VR game and that seeing somebody being disembowelled in front of me would have little effect on me psychologically. (However, I ought to point out that my few experiences of VR have left me feeling sick as I suffer from motion sickness). However, you can never rule out a small minority of individuals that it may negatively affect either psychologically or traumatically. In short, I don’t have many concerns about this until scientific evidence proves otherwise.

May also interviewed Professor Tanya Krzywinska, Director of the Games Academy at Falmouth University who thinks that VR and horror video games are a good match:

“VR is the next natural step for one of gaming’s most popular genres. Horror made its way into video games very early on [such as] the 1995 point and click ‘Phantasmagoria’ [was] an early breakthrough game due to its use of video snippets to show a ‘real’ actress reacting to the horrific events as they unfolded around her…’Silent Hill’ [was also] a game-changer for its use of sound and its surreal ‘Twin Peak-ish twist’ on survival horror. Both these games utilise a particular emotional palette that I regard as central to games: a sense of claustrophobia and the sense of being unable to act effectively on a situation…VR can make very good use of this palette because of its immersive nature and I think horror is one of the few genres that VR really suits…Horror is very inclined to want to take advantage of new formats to refresh the palette and work with the cache that the novelty provides. Without that novelty, repetition occurs and you then only manage to engage younger audiences who haven’t been around the horror block. Horror is a very suitable place to take a good, long, critical look at ethics and I hope that some game designers see that”.

So is the introduction of VR for the horror genre a game-changer? May also interviewed the independent games developer Sergio Hidalgo, creator of the creepy dungeon game Dreadhalls. He was quoted as saying:

“VR can work as an immersion multiplier, and given that the horror genre is built on immersion, it simply opens more opportunities to create experiences that take advantage of that sense of physicality it can provide. Simply being in a scary environment can be a very engaging experience in VR on its own. This was already true when I started ‘Dreadhalls’ but the technology keeps moving forward and improving with new developments such as room scale or motion tracked controllers…In ‘Dreadhalls’ there are monsters that react to the player’s gaze direction, forcing the player to either not look at them directly or the opposite. This is a much richer interaction when the player is performing it herself rather than via a mouse or controller. ‘Dreadhalls would never have gathered such attention if it weren’t for the new types of interactions and features made possible by VR tech…The main ethical recommendation I have in this regard is that of not betraying the player’s trust. When the player enters a VR experience and surrenders control over their senses to the developer, it’s important that [the players are] aware of exactly what to expect, and that this promise isn’t broken by the developer”.

unknown

In an interview that May had with Ben Tester, the games developer of VR horror game Don’t Knock Twice, Tester noted:

“Developers are in a strange predicament where it’s now possible to make a game that’s too scary. For that reason, ‘Don’t Knock Twice’ includes traditional adventure gameplay elements, such as puzzle solving and environmental props, to aid storytelling and remind the player every once in a while that they are still playing a game. We want to make a great horror game that people will remember for sure but we don’t want to make it so uncomfortable that it makes it unplayable. In ‘Don’t Knock Twice’, we want to avoid the player going through a constant stream of scares one after another and instead, create an interesting and atmospheric environment which will creep out any horror enthusiast. It’s about finding the right balance between having a solid gaming experience and immersing the player in a terrifying horror situation…In the VR demo of ‘Don’t Knock Twice’, players can break down a door with an axe. [This often leads to players] leaning their heads forward and triggering the classic ‘Here’s Johnny’ moment [from ‘The Shining’], which only amplifies the jump scare which follows. A scare that wouldn’t have been half as effective if it was in traditional gaming style”.

Finally, May asked me for some advice for those who were scared witless by playing VR horror games. My quoted response? “Just shut your eyes”.

Dr. Mark Griffiths, Professor of Behavioural Addiction, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

Ashcroft, S. (2015). VR revenue to hit $21.8 billion by 2020. Wareable, July 29. Located at: http://www.wareable.com/vr/vr-revenues-could-reach-dollar-218-billion-by-2020-1451

Griffiths, M.D. (2016). Can virtual reality be addictive? Virtual Reality News, June 28. Located at: http://www.virtualreality-news.net/news/2016/jun/28/can-virtual-reality-really-be-addictive/

Juniper Research (2016). White paper: The rise of virtual reality. Available from: http://www.juniperresearch.com/document-library/white-papers/the-rise-of-virtual-reality

May, G. (2016). Could VR horror be too…horrifying? Wareable, November 3. Located at: http://www.wareable.com/vr/virtual-reality-horror-experiences-too-real-ethics-55

Ortiz de Gortari, A.B. & Griffiths, M.D. (2015). Game Transfer Phenomena and its associated factors: An exploratory empirical online survey study. Computers in Human Behavior, 51, 195-202.

Ortiz de Gortari, A.B., Oldfield, B. & Griffiths, M.D. (2016). An empirical examination of factors associated with Game Transfer Phenomena severity. Computers in Human Behavior, 64, 274-284.

Ortiz de Gortari, A.B., Pontes, H.M. & Griffiths, M.D. (2015). The Game Transfer Phenomena Scale: An instrument for investigating the non-volitional effects of video game playing. Cyberpsychology, Behavior and Social Networking, 18, 588-594.

Stables, J. (2016).  Gambling, gaming and porn: Research says VR is set to blast off. Wareable, September 15. Located at: http://www.wareable.com/vr/gaming-gambling-and-porn-research-says-vr-is-set-to-blast-off-1682

Sung, D. (2015). VR and vice: Are we heading for mass addiction to virtual reality fantasies? Wareable, October 15. Located at: http://www.wareable.com/vr/vr-and-vice-9232

Tractica (2015). Virtual reality for consumer markets. Available at: https://www.tractica.com/research/virtual-reality-for-consumer-markets/

Wood, R.T.A. & Griffiths, M.D. (2007). Time loss whilst playing video games: Is there a relationship to addictive behaviours? International Journal of Mental Health and Addiction, 5, 141-149.

Wood, R.T.A., Griffiths, M.D. & Parke, A. (2007). Experiences of time loss among videogame players: An empirical study. CyberPsychology and Behavior, 10, 45-56.

Sense and sense-ability: A brief look at ‘virtual reality addiction’

Ever since I started researching into technological addictions, I have always speculated that ‘virtual reality addiction’ was something that psychologists would need to keep an eye on. In 1995, I coined the term ‘technological addictions’ in a paper of the same name in the journal Clinical Psychology Forum. In the conclusions of that paper I asserted:

“There is little doubt that activities involving person-machine interactivity are here to stay and that with the introduction of such things [as] virtual reality consoles, the number of potential technological addictions (and addicts) will increase. Although there is little empirical evidence for technological addictions as clinical entities at present, extrapolations from research into fruit machine addiction and the exploratory research into video game addiction suggest that they do (and will) exist”.

Although I wrote the paper over 20 years ago, there is little scientific evidence (as yet) that individuals have become addicted to virtual reality (VR). However, that is probably more to do with the fact that – until very recently – there had been little in the way of affordable VR headsets. (I ought to just add that when I use the term ‘VR addiction’ what I am really talking about is addiction to the applications that can be utilized via VR hardware rather than the VR hardware itself).

vr-addiction-1444927129-wpbo-full-width-inline

VR’s potential in mass commercial markets appears to be finally taking off because of mass-produced affordable hardware such as Oculus Rift, HTC Vive, PlayStation VR and the (ultra-cheap) Google Cardboard (in which a smartphone can be inserted into cardboard VR headset frame). Last year, a report by the marketing and consulting company Tractica claimed that spending on virtual reality hardware could be as much as $21.8 billion (US) by 2020. A more recent report by online and digital market research company Juniper estimated that global sales of VR headsets would rise from 3 million in 2016 to 30 million by 2020. Three markets are likely drive sales, and they all happen to be areas that I research into from an addiction perspective – video gaming, gambling, and sex. I’ve noted in many of my academic papers over the years (particularly my early papers on online gambling addiction and online sex addiction) that when new technological advances occur, the sex and gambling industries always appear to be the first to invest and produce commercial products and services using such technologies, and VR is no different. As an online article in Wareable by Dan Sung on VR sex noted:

“What [VR] headsets offer is immersion; 180-degree (or more), stereoscopic action with you as the star of the show and the adult actors and actresses looking deep and lustfully into your eyes as they tend to your genitalia. It’s small wonder that users have been donning their headsets and earphones in numbers and praying to their god that nobody walks in. Yet gambling and porn are synonymous with addiction, and increasingly, questions are being asked about whether the VR revolution could finally ensnare us humans into virtual worlds”.

I was interviewed by Sung for the same article and I made a number of different observations about VR sex. I commented that in terms of people feeling reinforced, aroused, rewarded, sex is the ultimate in things that are potentially addictive. Sex is one of those activities that is highly reinforcing, it’s highly rewarding and how people feel is probably better than the highs and buzzes from other behaviours. Theoretically, I can see that VR sex addiction would be possible but I don’t think it’s going to be on the same scale as other more traditional addictions. The thing about VR (and VR sex) – and similarly to the internet – is that it’s non-face-to-face, it’s non-threatening, it’s destigmatising, and it’s non-alienating. VR sex could be like that whether it’s with fictitious partners, someone that you’re actually into, or someone that you’ve never met before. Where VR sex is concerned, if you can create a celebrity in a totally fictitious way, that will happen. There may be celebrities out there that will actually endorse this and can make money and commercialise themselves to do that. It can work both ways. Some people might find it creepy while others might see something they can make money from.

In one of my previous blogs I looked at the area of ‘teledildonics’, a VR technology that has been around for over two decades (in fact I was first interviewed on this topic on a 1993 Channel 4 television programme called Checkout ’93). Dan Sung also interviewed Kyle Machulis who runs the Metafetish teledildonics website for his article. He said that in relation to VR sex there is a problem with haptics (i.e., the science of applying tactile sensation and control to interaction with computer applications):

 “We’re good on video and audio but haptics is a really, really hard problem…A lot of toys out there right now are horrible and it’s very hard to come up with something quality. So, instead, what the porn industry is aiming for right now is immersion. It may not feel better but they’re so much closer to the action that it may be better, and I think we’re on the cusp of that right now.” First, we need consumer hardware. We need things to be released and available to customers to see if it’s really going to take off or not. But when this happens – late this year, the beginning of next – as soon as the headsets are available, the media is ready and waiting…Of course, there’s straight women, gay men and gay women to develop for too but, for a lot of people, the perfect porn experience is doing something that’s not even physically possible – either through the laws of physics or the laws of land, and that’s something that only VR can solve…Even so, what we saw in teledildonics in gaming is that people used them to begin with but there’s always a lot of fall off with new technologies like this. So, there’s going to be a hardcore set of people who stay with VR porn but it’s hard to say how popular it will be beyond that. We’re all still guessing at the moment. This time next year it will be a completely different story”.

Another area that we will need to monitor is how the gambling industry will harness VR technology. The most obvious application of VR in the gambling world is in the online gambling sector. I can imagine some online gamblers wanting their gambling experiences to be more immersive and for their online gambling sessions to be more akin to gambling offline surrounded by the sights and sounds of an offline gambling venue. There is no technical reason that I know of why people that gamble via their computers, laptops, smartphones or tablets could not wear VR headsets and be playing poker opposite a virtual opponent while still sat on the sofa at home. As Paul Swaddle (CEO of Pocket App) noted in a recent issue of Gambling Insider:

We already know that participation in online gambling is snowballing, so if the entertainment industry can use VR to simulate the experience of being inside a video game, or social media sites can give you the opportunity to not just see your friends’ pictures, but to walk through them, why shouldn’t online casinos be able to do the same? VR may actually be the hook that mobile and online casinos need to draw in more millennials, with the average age of players in mobile casinos currently being 40 [years old], and the average age of mobile gamblers in general being 35 [years old]. Millennials simply aren’t engaging with mobile and online casinos to the same extent as older generations, and I suspect that this is down to younger players being much more used to immersive and sociable gaming, as a result of the cutting-edge developments that are being constantly rolled out in the video gaming industry”.

I agree with Swaddle’s observations as the gambling industry are constantly thinking about the ways to bring in newer players. Today’s modern screenagers love technology and do not appear to have any hang-ups about using wearable technology including Fitbit and the Apple Watch. As Swaddle goes on to say:

“By using 
VR technology to transport players and their friends to exciting locations for their online gambling experience, such as a famous casino in Las Vegas, or a smoky basement room in 1920s New York, or even to the poker table in the James Bond film Casino Royale, mobile and online casinos may stand a better chance of drawing in younger audiences if they use VR to gamify the casino experience”.

Again, this makes a lot of sense to me and I wouldn’t bet against this happening. Swaddle thinks that such VR gambling experiences will become commonplace in the years to come and that the gambling industry needs to get on the VR bandwagon now. 

Perhaps of most psychological concern is the use of VR in video gaming. There is a small minority of players out there who are already experiencing genuine addictions to online gaming. VR takes immersive gaming to the next level, and for those that use games as a method of coping and escape from the problems they have in the real world it’s not hard to see how a minority of individuals will prefer to spend a significant amount of their waking time in VR environments rather than their real life.

Dr Mark Griffiths, Professor of Behavioural Addiction, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

Ashcroft, S. (2015). VR revenue to hit $21.8 billion by 2020. Wareable, July 29. Located at: http://www.wareable.com/vr/vr-revenues-could-reach-dollar-218-billion-by-2020-1451

Griffiths, M.D. (1995). Technological addictions. Clinical Psychology Forum, 76, 14-19.

Griffiths, M.D. (1996). Gambling on the internet: A brief note. Journal of Gambling Studies, 12, 471-474.

Griffiths, M.D.  (2001).  Sex on the internet: Observations and implications for sex addiction. Journal of Sex Research, 38, 333-342.

Griffiths, M.D. (2003). Internet gambling: Issues, concerns and recommendations. CyberPsychology and Behavior, 6, 557-568.

Griffiths, M.D. (2012). Internet sex addiction: A review of empirical research. Addiction Research and Theory, 20, 111-124.

Griffiths, M.D., Király, O., M. Pontes, H.M. & Demetrovics, Z. (2015). An overview of problematic gaming. In Starcevic, V. & Aboujaoude, E. (Eds.), Mental Health in the Digital Age: Grave Dangers, Great Promise (pp.27-55). Oxford: Oxford University Press.

Juniper Research (2016). White paper: The rise of virtual reality. Available from: http://www.juniperresearch.com/document-library/white-papers/the-rise-of-virtual-reality

Király, O., Nagygyörgy, K., Koronczai, B., Griffiths, M.D. & Demetrovics, Z. (2015). Assessment of problematic internet use and online video gaming. An overview of problematic gaming. In Starcevic, V. & Aboujaoude, E. (Eds.), Mental Health in the Digital Age: Grave Dangers, Great Promise (pp.46-68). Oxford: Oxford University Press.

Stables, J. (2016).  Gambling, gaming and porn: Research says VR is set to blast off. Wareable, September 15. Located at: http://www.wareable.com/vr/gaming-gambling-and-porn-research-says-vr-is-set-to-blast-off-1682

Swaddle, P. (2016). Is virtual reality the future of mobile and online gambling? Gambling Insider, 23, June 3, p.9

Sung, D. (2015). VR and vice: Are we heading for mass addiction to virtual reality fantasies? Wareable, October 15. Located at: http://www.wareable.com/vr/vr-and-vice-9232

Tractica (2015). Virtual reality for consumer markets. Available at: https://www.tractica.com/research/virtual-reality-for-consumer-markets/