For years, scientists have been stymied in their quest to understand dreams because they are unique events that cannot be replicated. Robert Stickgold and his Harvard Medical School colleagues reported in the Oct. 13, 2000 issue of Science that they were able to get 17 different people to see the same dream images. “Here we have a case where with high reliability we can get people to have predictable dreams,” said Stickgold, assistant professor of psychiatry based at the Massachusetts Mental Health Center. The researchers elicited the carbon-copy images by training 27 subjects to play the computer game Tetris over the course of three days. The game involves assembling geometric puzzle pieces. The researchers then monitored the subjects’ dreams on the first two evenings. Seventeen of the subjects — more than 60 percent of the total — reported dreaming at least once in the hour after they fell asleep. All reported the exact same dream images — falling Tetris pieces.