Oregon State University assistant professor of psychology Mei-Ching Lien has been studying people's ability to easily change topics or trains of thought on the fly while performing other tasks and believes that doing so is a difficult task for the human brain. For example, people talking on cell phones while driving are likely to experience "inattention and slow reaction times" especially when the conversation is involved, because the two tasks both require a level of complexity on the part of the driver. Lien did have one point to make about an activity that might mitigate this sort of problem:

In her lab studies, she has yet to test any volunteers who are immune to delays in multi-tasking, though she says some students do much better than others. "I have to say that the best ones are those who play a lot of video games," she pointed out. "Those are lab studies, however, and not driving tests."

Though she did not do any tests specifically testing a link between video game prowess and the ability to concentrate while driving and using a cell phone, her observation is one that crops up rather frequently in tests measuring mental sharpness if not necessarily suggesting anything about raw intelligence. So if you're worried about your brain rotting (or possibly melting) due to a gaming habit, know that you might just be a bit quicker on the uptake as well. Just don't forget to go outside sometimes too.