"Researchers at Oxford University hypothesized that playing Tetris after witnessing violence would sap some of the cognitive resources the brain would normally rely on to form memories. A well-structured study in the journal PLoS One confirmed the finding–Tetris acted like a ‘cognitive vaccine’ against traumatic memory. Memory research suggests that there’s about a 6-hour window immediately after witnessing trauma during which memory formation can be disrupted. The results of this study indicate that if you happen to have Tetris or a game like it handy during those six hours, it’s the cure for what ails you."