Answer: The Tetris Effect

If you’ve logged serious hours playing video games, there’s a very good chance you know exactly what the Tetris Effect is all about. Players who devote significant time to specific video games often find that patterns and imagery from that game work their way into their consciousness in unexpected ways. In the case of Tetris or other puzzle games, frequent players report seeing tetrominos (the iconic shapes that make up the game of Tetris) at the edges of their vision when they close their eyes, across their eyelids as they fall asleep, and they even dream about solving Tetris puzzles. Further, the pattern matching in the game often bleeds over into real life, wherein players will quickly identify patterns in otherwise unrelated objects (such as the layout of boxes on a store shelf).

The effect isn’t just limited to Tetris, although the term was coined in the late 20th century when Tetris was a widely played game and the uniqueness of the shapes made the effect stand out. Players who spend hours with games that have on-screen Heads Up Displays (HUDs), like those found in the popular multiplayer combat franchise Halo, also report both seeing the HUD in their dreams as well as reliving the game in their sleep.

While it might be unsettling the first time you experience the effect, there’s nothing to worry about. Not only is the Tetris Effect temporary (if you experience it at all, you’ll stop experiencing it shortly after you stop playing the game in question), but it’s completely harmless. If anything, the effect is a testament to the human brain’s incredibly well-honed ability to identify patterns and keep our brains primed to repeat them. If you’re training to be the world’s best Tetris master, your brain is right there trying to help you, keeping those tetrominos spinning and locking into place even as you drift off to sleep.