Psychologists have long speculated about the reasons for dreaming. Dreams can be so complex, vivid and surreal, which is why so many people have suggested that there must be some deeper purpose behind them.
According to a new study by sleep and dream expert J. Allan Hobson, dreams might just be the brain's way of preparing for all of experiences it will encounter upon waking.
"It helps explain a lot of things, like why people forget so many dreams," Dr. Hobson told The New York Times. "It's like jogging; the body doesn't remember every step, but it knows it has exercised. It has been tuned up. It's the same idea here: dreams are tuning the mind for conscious awareness."
You can read more about the study in this article from The New York Times: A Dream Interpretation: Tuneups for the Brain.
REM Sleep and Dreaming: Towards a Theory of Protoconsciousness - Nature Reviews Neuroscience 10, 803-813 (November 2009) | doi:10.1038/nrn2716