Sleeping

Despite the fact that sleep is a dominant activity during the early years, surprisingly little is known about why humans sleep. Aside from general agreement that sleep has restorative functions, evidence linking sleep to various waking behaviors is largely circumstantial. Sleep appears to play a role in behavioral regulation and in emotional and cognitive functioning. (Irritability, overactivity, and decreased attention span have been associated with sleep disruptions in children.) Sleep may also facilitate the consolidation of memories and, in older children and adults, REM sleep is associated with dreaming.

Whether or not infants dream is not known; REM sleep, however, may be important to infants in other ways. Newborns spend approximately 50 percent of sleep time in REM, an impressive amount when compared to six-month-olds whose REM approximates that of adults (25-30% of sleeping time). Many researchers believe that the heightened activity occurring during REM sleep stimulates brain growth.