The circadian rhythm that guides your daily cycle from sleep to wakefulness and back again may be doing much more than just that simple task.
Biologists have shown that a functioning circadian system is critical to hamsters' ability to remember what they have learned. Without it, in fact, they can't remember anything.
Hamsters whose circadian system was disabled consistently failed to remember their environment, unlike hamsters with normally functioning circadian systems.
Until now, it has never been shown that the circadian system is crucial to learning and memory. The change in learning retention appears to hinge on the amount of a neurochemical called GABA, which the circadian clock uses to control the daily cycle of sleep and wakefulness.