Some researchers, including Swiss scientist Arthur Funkhouser, firmly believe that precognitive dreams are the source of many déjà vu experiences. J.W. Dunne, an aeronautical engineer who designed planes in World War II, conducted studies in 1939 using students of Oxford University. His studies found 12.7 percent of his subjects' dreams to have similarities with future events. Recent studies, including one by Nancy Sondow in 1988, have had similar results of 10 percent.
These researchers also tied evidence of precognitive dreams to déjà vu experiences that occurred anywhere from one day to eight years later. The question has been raised about why the experiences themselves are typically mundane everyday things. One explanation from Funkhouser is that something more exciting is more likely to be remembered, making a déjà vu experience less likely.
Although déjà vu has been studied as a phenomenon for over a hundred years and researchers have advanced tens of theories about its cause, there is no simple explanation for what it means or why it happens. Perhaps as technology advances and we learn more about how the brain works, we will also learn more about why we experience this strange phenomenon.
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