The spreadsheet was seven feet long. Printed in nine-point font were the names of the perpetrators of mass killings, the models of weapons each had used, and the number of victims. The gruesome document was discovered at the home of Adam Lanza, who on 14 December 2012 fatally shot his mother, before killing 20 children and six teachers at the Sandy Hook Elementary School in Connecticut, and turning his assault rifle on himself.
It took only a few hours for the authorities to link the massacre to Lanza’s playing of violent video games. "[People heading the investigation] don't believe this was just a spreadsheet," a police officer later told the New York Daily News. "They believe it was a score sheet. This was the work of a video gamer, and it was his intent to put his own name at the very top of that list."
Lanza's shooting spree was just the latest of a long list of violent crimes that have blamed on video games. Scientists have evidence that virtual violence can trigger aggressive thoughts and anti-social behaviour, but most reject the idea that gaming can turn otherwise balanced individuals into killers.
A growing body of research is showing the flip side, though – video games can help people see better, learn more quickly, develop greater mental focus, become more spatially aware, estimate more accurately, and multitask more effectively. Some video games can even make young people more empathetic, helpful and sharing. As public debate on the subject is often highly emotive and polarised, and as more and more of us are becoming gamers, researchers say it is important to move beyond the generalisations that characterise much of the discussion.
"We know there are good sugars and bad sugars, and we don't discuss whether food in general is good or bad for us," says Daphne Bavelier, a neuroscientist at the University of Rochester, New York. "We need to be far more nuanced when we talk about the effects of video games."
Douglas Gentile at Iowa State University, US, agrees. "Game research has tended to get sucked down into a black hole of people yelling at each other, saying either games are good or games are bad," says Gentile, who studies the effects of video games on physiology and behaviour. "I think we are starting to move beyond this inappropriately simplistic idea to see games can be powerful teachers that we can harness."
Part of this has stemmed from the fact that 20th-Century video gaming research often failed to distinguish between game genres. Studies lumped together the different brain processes involved when racing cars, shooting baddies, street fighting, and completing puzzles. But with the benefit of hindsight, researchers now recognise they hold only limited insights into the impacts of video games.
Bavelier stumbled upon the particular effects action games may have on the brain by accident. She was designing a test to probe the effects of congenital deafness on visual attention, and while trialling it a young researcher in her department, Shawn Green, and his friends repeatedly scored far higher than expected. Eventually they realised their exceptional performance could be traced to their fondness for the action games Counter-Strike and Team Fortress Classic.
Bavelier and Green hypothesised that this type of game had distinct effects on the brain because achieving a high score requires players to react quickly, while processing information in their peripheral vision, multi-tasking, making predictions and processing the constant player feedback. In research published in 2003, they used a series of visual puzzles to demonstrate that individuals who played action games at least four days per week for a minimum of one hour per day were better than non-gamers at rapidly processing complex information, estimating numbers of objects, controlling where their attention was focused spatially, and switching rapidly between tasks.