According to a new study by researchers at the University of York, there is no evidence that video games make players more violent and otherwise increase aggression.
Basically, the team set out to discover whether realistically violent video games can be directly linked to violent and anti-social behavior in humans. In psychology, this idea is known as priming and argues that "exposing players to concepts, such as violence in a game, makes those concepts easier to use in 'real life.'"
Based on that theory, immersing yourself in shooter games or fighting games, such as Call of Duty or Mortal Kombat, where success depends on how many skulls you can crack, would impact your reaction to hostility in real life and, potentially, give you an outlet to "rehearse" violent acts that can later be applied in practice.
However, in a series of experiments with more than 3,000 participants, the team over at York University couldn't find evidence that this is, in fact, true.
One study was particularly focused on priming and had participants play one of the two games: a car avoiding a crash or a mouse avoiding being caught by a cat. They were then asked to look at a bundle of images and label the ones connected to their respective game. As Dr. David Zendle explains:
"If players are 'primed' through immersing themselves in the concepts of the game, they should be able to categorise the objects associated with this game [vehicle or animal] more quickly in the real world once the game had concluded.
Across the two games we didn’t find this to be the case. Participants who played a car-themed game were no quicker at categorising vehicle images, and indeed in some cases their reaction time was significantly slower."
The two other studies delved more into combat games and whether realism is a factor in influencing aggression of game players. All of the experiments produced findings that suggest "there is no link between [...] realism in games and the kind of effects that video games are commonly thought to have on their players."
The team agrees further studies are needed "into other aspects of realism" as well as ones that look into the effects on children players, not just adults. You can read the full research papers in the Computers in Human Behaviour journal.