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Damn Tetris blocks. Seeing them everywhere. Can’t sleep. Can’t turn them off.

For most of us, gaming offers a momentary escape from the real world, but for some, the distinction between onscreen actions and reality can blur. A recent study highlights how gaming can seriously affect our senses and offers a glimpse through the eyes of gamers whose brains keep on playing.

In the study, gamers talk about seeing a grenade icon from Call of Duty while out shopping and nearly commando-rolling away, a bedroom turning into a Minecraft-style grid, and a wide range of visual distortions that last long after a game is back in its box.

Not everyone is equally susceptible to these effects — likened to the symptoms of conditions such as epilepsy and schizophrenia — but should gamers experiencing them be concerned for their mental and physical well-being?


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And does the game industry need to take notice of this research?

The researcher

Angelica_Ortiz_de_GortariPsychologist Angelica Ortiz de Gortari (pictured) has investigated what she calls Game Transfer Phenomena (GTP) since 2010. These are typically visual after-effects, pseudo-hallucinations, and misperceptions that tend to get worse with prolonged exposure to video games.

Not limited to just the retained image of shapes seen on the back of the eyelids, commonly called the “Tetris Effect” — after Alexey Pajitnov’s seminal block-puzzle game — GTP can also be triggered by external stimuli and bring images, sounds, or distortions from games into the real world.

Ortiz de Gortari is a gamer herself and is keen that her work can help provide a greater understanding of the effect that video games can have on our minds, for better or worse.

“It is important to start to research with the video games we have today,” she told me via email, “to be prepared for the challenges the mind will affront due to the technologies that are still to come.”

What some gamers are seeing

Ortiz de Gortari’s most recent research paper, written with fellow psychologist Dr. Mark Griffiths, analyzed and classified reports of GTP. It examines a total of 656 experiences from 483 gamers across 54 online forums.

The types of experience are categorized as digitally induced images, seen on the back of the eyelids or projected into the environment; perceptual distortions, such as motion effects and time distortions; and visual misperceptions, where gamers incorrectly identified ambiguous stimuli as game-related objects.

Some of the most arresting examples are below:

Digitally induced images:

“After a long [Call of Duty:] Black Ops session, I saw a red player tag above a woman riding a bicycle. Fortunately, I didn’t have my gun on hand.” (Max4)

“Playing so much Rock Band, some songs make me see green, red, yellow, blue, and orange notes in my vision.” (Mayaz)

Perceptual Distortion:

“For the week or so before, I have been playing an old Final Fantasy game. Suddenly, during a lecture, I realized that the teacher’s head became pixelated. I was tired. I stared at him for some time, and then nothing he said made any sense.” (Joey)

“I played Minecraft for 72 hours straight. I went to bed, but I could not sleep. I turned the light on and looked around. Everything was on a square. [A] grid … I started freaking out, and I moved my furniture around to make it fit perfectly on the grid. My dresser did not fit on a square, and I went to bed crying.” (Sha)

Visual misperceptions:

“More recently with Left For Dead 2. I was at a store, and they had a frying pan on display; I could almost see a silhouette of the damn thing, and I was actually going to pick it up.” (Jenice)

“For minutes, I would confuse airplanes in the sky for [unmanned aerial vehicles] in [Call of Duty:] Modern Warfare 2.” (Fillipes)

Guitar Hero gameplay

Above: Guitar Hero players report long-lasting visual distortions.

Image Credit: Activision

Should gamers be concerned?

The sensory effects reported in this study are similar to some symptoms of pathological conditions such as photosensitive epilepsy, migraine aura, and schizophrenia. “For this reason,” says Ortiz de Gortari, “one of the main goals of the GTP studies is to raise awareness, explain and demystify these experiences so gamers don’t interpret GTP as pathological.”

That isn’t to say gamers should ignore them.

Ortiz de Gortari says that while GTP effects usually last only a few seconds or minutes, these experiences should concern gamers if they occur over and over or if the effects last for prolonged periods of time. She says it’s important for gamers to reflect on their gaming habits and ask themselves if the GTP are causing distress, affecting day-to-day life, or causing them to question their own mental health.

The Tetris Effect was first documented in 1994

Above: The Tetris Effect was first documented in 1994.

Image Credit: YouTube

From the psychiatrist’s chair

Dr. Victoria DunckleyPsychiatrist Dr. Victoria Dunckley (pictured) has a history of treating patients with psychotic symptoms linked to playing video games. The effects that video games and other electronic screens are having on child and adult mental health are of great concern to her.

Gamers experiencing altered perceptions should absolutely be concerned, said Dr. Dunckley via email: “Feeling as though you’re in a game, auditory hallucinations, vague paranoia, or sustained visual symptoms should be taken seriously. Even transient visual symptoms are a sign that the brain is being stressed.”

She feels that such events are likely underreported and are actually more common than we realize: “Typically, when I see gaming-related psychosis, there is some vulnerability, such as Asperger’s or autism, a mood disorder, or a family history of mental illness. But pooled together, these vulnerabilities cover a large percentage of the population.”

There are two major concerns here,” she said. “One is the risk of precipitating a serious mental illness that wouldn’t have occurred otherwise, and the other is engaging in unsafe, bizarre, or criminal behavior while acting out a game. I’ve witnessed both, and the consequences can be devastating.”

Don’t game and drive

Gamers experiencing GTP are very rarely in control of the effects, which presents wider safety implications.

“Certainly, the intrusive and unexpected nature of the altered perceptions raise concerns,” Ortiz de Gortari told me, “especially when automatic associations result in gamers seeing video games images in circumstances where automatic responses can put gamers and others around them in risk — [such as] seeing images on the highway.”

A perfect example can be seen on The Escapist forum. “When playing [first-person shooter] Battlefield 2 awhile back, I once saw a landmine on the road,” said forum member Tattaglia, “and I swerved to avoid it. In the middle of town. Hilarity ensued, and by hilarity, I mean a ticket.”

Forza Horizon 1

Above: Some gamers report seeing visual effects while driving, including extra white lines, minimaps, and even landmines.

I spoke about this issue to Peter Wright, the managing director of U.K. law firm DigitalLawUK, after he expressed interest in the research via Twitter.

“Given respondents have reported distorted versions of real-world surroundings,” said Wright via email, “… it raises real concerns over the long-term ability of those who are displaying such phenomena to operate machinery or undertake dangerous day-to-day tasks like driving or even crossing the road. Driving requires split-second decisions and the reading ahead of how other road users are behaving. If that ability is impaired in any way, reaction times could be increased with potentially fatal consequences for other road users.”

The potential for tighter regulation on gaming and driving is there, said Wright, but it would depend on further studies, along with some cases where GTP causes incidents, accidents, or even death.

“In extreme cases,” he said, “it is not difficult to imagine the police having a test for drivers that they pull over after seeing them drive erratically to check whether they are in full control of their senses. Currently, such tests are focused on alcohol and drug use, but if a driver were asked to take a few paces, strand on one leg, [and] answer a few questions, it may establish if the driver is experiencing Game Transfer Phenomenon.”

The gaming industry response

Ortiz de Gortari told me she’s received no feedback from game developers about the health and safety implications of GTP. One developer has accused her of trying to harm the video game industry, however.

Ortiz de Gortari says GTP shouldn’t be viewed as a solely negative issue, though. “GTP tells us a lot about how the human mind works,” she says. “[It] shows us how certain individuals respond to sensorial hyper-stimulation, but most importantly, how the human mind constantly establishes associations between stimuli without [our] awareness.”

She points out that the study shows examples of games enhancing visual memory, creating synaesthesia-like experiences, and enabling gamers to see manifestations of their thoughts. “Perhaps if the visualizations of video game elements can be controlled, it can enhance our minds in interesting ways,” she says.

Not all gamers are susceptible to GTP, and not all games affect people in the same way. Ortiz de Gortari’s ongoing research is now looking at factors that influence and can predict GTP. Identifying these could help gamers and game designers minimize its effects.

I reached out to hardware manufacturers Nintendo and Sony Computer Entertainment, Guitar Hero developer Harmonix, and publisher Electronic Arts about the effects of GTP. None of them responded with a comment.

Visual effects can be worse if you game late at night

Above: Visual effects can be worse if you game late at night.

Image Credit: Rum Bucolic Ape/Flickr

How to prevent GTP

With no specific health and safety recommendations from developers or publishers, I asked Ortiz de Gortari for her tips on avoiding unwanted visual effects from gaming. Unfortunately, as she points out, the best advice goes against what gamers typically want to do: get immersed, play for a prolonged time, and game during the evenings.

Tip 1: Moderate the time invested in playing games

Excessive gaming may precipitate GTP. Some gamers have reported that GTP occurred the first time they played the game, however, so certain altered perceptions may disappear by themselves — similar to the symptoms of motion sickness — but this is not yet clear.

Tip 2: Don’t play video games when tired, sleep deprived, or hungry

Typically, perceptual distortions and hallucinations are more likely to occur when people are sleep deprived, feeling hungry, or under the influence of substances.

Tip 3: Take breaks to connect with reality during long gaming sessions

Prolonged gaming sessions that disconnect us from reality may strengthen the effects of GTP in certain people. Take breaks to connect with the real world during long sessions.

Tip 4: Try to not play video games directly before going to bed

Gaming directly before bed may facilitate seeing video game images in the back of the eye lids and could lead to sleep deprivation. Reducing the exposure to stereotypical and monotonous visual effects before bed may help prevent GTP.

Angelica Ortiz de Gortari has also created a series of cartoons on her blog to help understand and demystify the effects of GTP. A selection of these are in the gallery below:

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