The video game industry is a global phenomenon. There are more than 1.2 billion gamers across the planet, with sales projected soon to pass $100bn (£65bn) per year. The games frequently stand accused of causing violence and addiction. Yet three decades of research have failed to produce consensus among scientists. In laboratory studies, some researchers have found an increase of about 4% in gamers' levels of aggression after playing violent games. Image A growing body of evidence suggests video games can affect the brain's development But other research groups have concluded factors such as family background, mental health or simply being male are more significant in determining levels of aggression. What is certain is that science has failed to find a causal link between video games and real-world acts of violence. But away from the controversy, a growing body of work is beginning to show these games in a different light. Psychologists split over whether video games c