Robert Stickgold caused 17 different people to have the same dream. One startling outcome of the research shows that amnesiacs do the same kind of processing although they cannot make the same memories. They do, and their heads feel less cluttered in the morning. The most logical conclusion is that it's processing information received during the day. To demonstrate this, Stickgold and his colleagues at Harvard and the Massachusetts Mental Health Center had 22 college students and five amnesiacs play the computer game Tetris.
Players try to position falling blocks of different shapes so that they completely fill up lines.
The blocks come down at varying speeds from the top of a space. Filling the whole space with solid lines of blocks wins the game. Gaps in the space lose the game. When the players went to sleep on game days, Stickgold's colleagues woke them up every few minutes during the first hour after they dozed off, and asked them about dreams or images they were experiencing. That made it a tough night for 27 people, but the researchers obtained good information about dreams.