That's the finding of a study out of Oxford University, published this week in PloS ONE.
For the experiment, the researchers had 60 subjects watch a movie with images of traumatic injuries, an established method of studying effects of trauma.
For 30 minutes after the film, 20 of the subjects played Tetris for 10 minutes. For the Nintendo-deprived, Tetris is a puzzle game in which players try to fit falling blocks of varying shape in the most space-efficient manner. Another group of 20 subjects played Pub Quiz, a video quiz game. The third group of subjects did nothing.
The Tetris players had significantly fewer flashbacks of the film than either of the two groups. Oddly, the subjects who played Pub Quiz had significantly more flashbacks than the other two groups.