If you read the newspapers, you may get the impression that video games and other forms of digital technology are damaging our brains. They cause aggression and "deviant behaviour"; they cause dementia, may be linked to attention deficit disorder, and are "taking away our sense of reality".
But is any of this true? We asked five neurologists and psychologists with an interest in the topic.
Dr Andrew Przybylski, research fellow at the Oxford Internet Institute
"There isn't any evidence that there are any harms inflicted on young people, or adults. But there is lots of evidence that hints at potential risks, studies that say we need to look more closely at this or that we need to do more work. It's hard to establish whether video games cause aggression. Violent video games are fun. We did an experiment in which we modified the game Half-Life 2 to make it either more or less violent, and looked at whether people enjoyed the game more. We found that people who were already in an aggressive state of mind were more likely to want to carry on playing the violent version than people who weren't, while people who weren't feeling aggressive found the violence a turn-off.
"We need to think about these risks in context. With games, we're talking about a worst-case scenario of a single-digit percentage increase in aggression. That is, if you ignore all the other factors, social background, gender, education, and so on, then on an aggression-measurement percentage scale of 0–100, playing violent video games might increase your score by 4%. Conversely, if you have a positive experience of playing video games, it increases your score on scales of things like social connectedness by 10 or 15.
"There are reasons to think that there might be risks, but there are so many other things that definitely cause harm. There's lots of evidence that lead damages brain development, for instance, and lots of countries still have leaded petrol. The focus on video games' small possible harms is disproportionate."
Berni Good of Cyberpsychologist
"The evidence for negative effects of video games on developing minds is very grey, because the technology has advanced so quickly and science is struggling to keep up. Also, the field of cyberpsychology is very new. But there was a really good five-year longitudinal study in the US recently, one of a very few longitudinal studies. There have been a lot of stories recently along the lines of an 18-year-old holds up a bank, and the judge says that he played Grand Theft Auto, and the question is: If people play violent games, do they take that violence offline?
"And this research, which looked at American males from the age of 14, showed that crime went down among those who played more violent games. It suggests that if people are able to vent their frustrations in a virtual world, they're less likely to do so offline.
"The consensus about negative impacts, I think, is that it's a grey area and there needs to be lots more research. The situation with positive impacts is very different. Effectively what we're seeing is that people who play Call of Duty have their cognitive abilities boosted, in a comparable way to people who learn to read music. People who play these action-packed first-person shooter games, for instance, can detect more colours than the rest of us, because they've trained their brain to attend to more information.
"Also, research suggests that when someone engages in video games it gives them a sense of competence, of mastery, which is a human psychological need. It also gives people a feeling of relating to one another, and a sense of autonomy. We often don't feel we have that much control in our lives – we've got bills, commitments. But in a video game you can choose your weapons, choose your maps. It's hard to know whether there are negative effects in normal players (I'm not talking about the 14-hour-a-day addicts, that's obviously not good). But the positive effects are well-documented."
Dr Pete Etchells, a lecturer in biological psychology at Bath Spa University
"The trouble with asking what the effects of video games are is that it's a really ambiguous question, like asking what the effects of eating are. There are so many different types of video games out there. So the effects of two hours of Call of Duty against other people online are going to be different to two hours of Candy Crush on the commute. So the problem with a lot of research is that the term 'video game' is so poorly defined it's essentially meaningless. Similarly, if the question is 'Does playing violent video games cause aggression?', what do you mean by aggression?
"There's also a tendency for claims about the effects of games to get exaggerated in the media. We saw this recently with claims that playing games like Call of Duty might increase the risk of Alzheimer's disease. In fact, the study in question had nothing to do with Alzheimer's disease. But because this sort of thing happens so often, it's understandable that people might be worried.
"The honest answer is that we don't really know yet – video games research is in relative infancy, and struggles to keep up with the pace of video game development. Any effects that we do see – positive or negative – are likely to be small, and need to be considered within the wider context in which video games are used. For example, a longitudinal study from 2013 looked at whether there was an association between things like watching television or playing video games (all lumped together as 'screen time') at age 5, and behavioural problems at age 7. When the researchers looked at screen time on its own, they found an association between with things like hyperactivity and conduct disorder. However, when the researchers took into account a number of confounding factors – things like the frequency of parent-child activities – the associations with video games pretty much disappeared.
"That's just one study, and there are others out there that suggest that an association between video game use and negative behavioural outcomes. But there are lots of potential problems and pitfalls with research in this area. Ultimately, there isn't clear evidence to suggest that we should be especially worried about video games any more any other type of leisure activity."
"Neuroskeptic", a neuroscientist and blogger for Discover magazine
"Overall I don't think we know very much about how technology affects the brain. There's research looking at the short-term impact of, say, playing a video game on brain activity. This is interesting, but these studies don't tell us much about impacts on the brain, because everything we do affects brain activity. So the fact that a game alters our brain activity is no surprise. Brain activity is always changing from moment to moment.
"I don't know of any controlled studies looking at the long-term impact of our use of technology on the brain; there's research looking at correlations between technology use and brain structure or function but these are not controlled studies, correlation is not causation, so I don't think we can conclude much from them.
"So for instance there are studies showing that brain structure is slightly different in 'internet addicts' compared to other people, but that doesn't mean the internet changed their brains. Their brains might have been different beforehand, making them vulnerable to the addiction.
"In my view it's more important to look at technology's impact on behaviour, rather than on the brain. Does a technology cause us to act smarter, less smart, or to be more kind, or more violent? For example, crime rates have been falling over the past two decades. Did technology contribute to that? I don't know, but I think that's an important question."
Professor C Shawn Green, Department of Psychology, University of Westminster
"The first really important thing to emphasise is that the term 'video games' encompasses such a wide range of activities that it basically has no predictive value whatsoever. The analogy I always use is that trying to ask what impact 'playing video games' has on the brain is like trying to ask what impact 'eating foods' has on the body. In my own research, we've looked at the impact of playing one sub-type of video games, action video games. Playing this type of game leads to clear enhancements in a variety of cognitive skills. It's really critical though to note that not all games lead to these enhancements in cognitive function.
"One thing to note is that most of this work has been done in college-aged adults, not children. But we can examine the cognitive abilities of children whose parents allow them to play action games. And the effects there look pretty consistent with what we see in adults. There is also work linking playing pro-social video games with increases in empathy, helping, and overall pro-social behaviour, and some linking certain video games with enhancements in creativity and problem-solving.
"On the negative side there is an emerging belief that some people can become 'problem gamers', in that their playing starts to adversely affect their lives and they persist in playing despite these negative outcomes. The newest version of the Diagnostic and Statistical Manual of Mental Disorders lists 'Internet Gaming Disorder' as an area in need of future research. There's still a lot that we don't know in this domain, though.
"When parents/educators ask me if I think kids should be playing video games, my response is typically that I think that kids (and everyone, not just kids) should do a variety of things every day that are cognitively and physically stimulating, and video games can fall into that category. However, there are few things in life where only doing that one thing is very good for you, and video games definitely fall into that category as well."