A new McMaster University study shows that video gamers have better memory elasticity, handling of complexity, and faster brains (in milliseconds) than non gamers. The 45 millisecond difference in reaction time approximates Cognitive Labs' observations (conducted by Dr. Michael Addicott) on individuals playing Halo2, who then were tested on Cognitive Labs test 4. *Research conducted at a dedicated offsite facility in Los Angeles during E3. Halo2 gamers average score on this test was in the fastest 99th percentile, with 2 individuals achieving greater than 99.5%, a statistical 100%.
Here's the study.