How Tetris, now 30 years old, helps explain dreams

You've played it on your computer, your phone, and your tablet, passing time on the Subway or distracting yourself at the back of class. But, oh, where did the time go? Tetris, the gaming sensation that's been entertaining users from the age of the Game Boy to the age of the smart phone, turns 30 today. 

Developed by Russian video game designer Alexey Pajitnov and released on June 6, 1984, the game is simple: Users must arrange and rearrange blocks of different sizes and shapes as they stream down from the top of the screen. The goal is to create as many complete rows of blocks as possible before all the blocks pile up and reach the top of the screen. Once that happens, game over. 

With the help of Dutch video game designer and entrepreneur Henk Rogers, Tetris became the bundled game for Nintendo's Game Boy, which was released in Japan in 1989, garnering worldwide appeal for the game and the console that released it to the masses. Since then, in its three decades of existence the game has generated "over 425 million paid mobile downloads today," according to Time, with more than "a billion games played online per month," according the SoMa Play, which designs new versions of the classic game. In March, in preparation for its 30th anniversary, the Tetris Company announced that the game would be featured on Xbox One and Playstation 4, as part of a partnership with SoMa Play and publisher Ubisoft. 

The ever-popular game is known not only for its entertainment value, but also for what has been termed the "Tetris effect." Namely, the idea that when you play the game long enough that it begins to affect your thoughts and dreams long after you've stopped rearranging the blocks. 

This theory was given credence in a 2000 paper published in Science Magazine by Harvard psychiatry professor Robert Stickgold. The paper describes the way in which people build on their waking experiences while they sleep. To demonstrate this idea, he had 27 people play seven hours of Tetris over three days. Of those participants, more than 60 percent reported seeing images of Tetris pieces as they slept. "It turns out when you start playing Tetris, you go to bed at night, you lie down in bed, and you see Tetris pieces falling down in front of your eyes," Mr. Stickgold said in an interview with NPR's Radiolab. 

Based on these tests, Stickgold could come to the conclusion that the events and actions of someone's daily life play a critical role in the dreams they have. But in dreams, he says, people take risks and make connections that went unnoticed while awake.

"Dreaming is a time when we try out possibilities that in waking we might not feel were worth trying," he said in the Radiolab interview. "And when it works, it can be profoundly important."