While dreams have had a marked influence on mysticism, philosophy, and people's general decision-making throughout recorded history, humans probably aren't even the most prolific dreamers. On average, we experience dreams for about two hours a night, the duration of our REM cycle. Platypuses, on the other hand, have a REM phase that lasts as much as 8 hours a day -- the longest of any animal.
Still, scientists have yet to uncover what role dreaming plays in the life of animals, ourselves included.
"One theory regarding the role of dreams in memory is that dreams may provide the opportunity to bring together experiences that were related, but did not occur at the same time, in order to learn from them,"says Wilson.
"For example, replaying a series of pleasant or unpleasant experiences may allow us to learn what these experiences had in common and use this to guide future behavior."