Memory

The Tetris Effect Is When Things You Focus On Appear In Your Dreams

Just like having sea legs after a long boat ride or getting a song stuck in your head after listening to it on repeat, if you play Tetris for days on end, your brain will keep playing while you sleep. This is known as the Tetris effect, and it happens with all sorts of tasks—not just games.

Why It's Relevant

Have you ever done something for so long that you see it in your sleep? Perhaps you see Candy Crush pieces flying around you, or the Excel spreadsheet you were working on turns into a giant maze. Then, you wake up and wonder if you have an addiction (or you're working too hard). There's a name for this phenomenon, named after the classic game of connecting geometric shapes—the Tetris effect.

The idea was first put into words by author Jeffrey Goldsmith in a 1994 WIRED article: "At night, geometric shapes fell in the darkness as I lay on loaned tatami floor space. Days, I sat on a lavender suede sofa and played Tetris furiously. During rare jaunts from the house, I visually fit cars and trees and people together." Since then, this so-called game transfer phenomenon has helped scientists explore both memory and brain structure.

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How It Works

In 2000, a Harvard psychiatrist named Robert Stickgold pondered why he kept feeling the sensation of scaling rocks in his sleep after a day of mountain climbing. Even when he tried to think of something else, the images remained stuck in his brain (these are known as hypnagogic images). To find out, he launched a study with a group of college students in the Harvard sleep lab.

After playing Tetris for several hours before turning in, 60 percent of the students reported seeing Tetris pieces floating in their vision as they drifted off to sleep. While they slept, their minds continued to make sense of the game. What's most remarkable about this study is that two students with amnesia still pictured blocks turning on their sides in their sleep even though they couldn't later recall playing the game at all.

But why? It all has to do with how our brains process memories. Your brain's hippocampus stores explicit memories (the "knowing what") from real-life events, while your cerebral stores cortex more procedural, implicit memories (the "knowing how")—like how to rule at Tetris. The same process happens when you have an earworm. The fact that amnesiacs, who had damage to the hippocampus, still saw Tetris blocks in their sleep means that the Tetris effect happens in the brain's implicit memory system.

While mastering Tetris is certainly impressive, Shawn Anchor writes about harnessing this ability for more positive effects in his book "The Happiness Advantage." He calls this "The Positive Tetris Effect" and claims that we can possibly build more beneficial habits for our brains, such as learning a new language. For now, however, we know that you can try chewing bubble gum to get that pesky holiday jingle out of your head.

Editors' Picks: Our Favorite Videos About Brain Habits

The Tetris Effect Takes Many Forms

The Tetris effect is similar to seeing a lingering glow after staring at a bright light, only the afterimage is in your brain.

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Your Brain On Tetris

Can Tetris make your brain more efficient?

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Key Facts In This Video

  1. Playing Tetris may reduce flashbacks for people with post-traumatic stress disorder (PTSD). 01:05

  2. Tetris is addictive because it appeals to our natural desire to organize things, complete tasks and achieve goals. 01:43

  3. The pace of Tetris forces players to think with the game instead of about it, which is called Epistemic Action. 02:22

Where Did Tetris Come From?

Alexey Pajitnov changed the world of gaming forever when he created Tetris in the 1980s.

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Key Facts In This Video

  1. Tetris was programmed in two weeks, without any colors or graphics. 00:52

  2. Hungary was the first country to begin distributing the game. 01:19

  3. The game's inventor later worked for Microsoft as the company's first game designer. 01:37

Written By
Curiosity Staff
December 21, 2016