[Function of REM sleep]

The author gives a review of the biological and psychological functions ascribed to paradoxical sleep. Most of the investigative work in the field has been dedicated to proving a relationship between REM sleep and learning. For intellectual learning the evidence is inconclusive, whereas there do seem to exist some ties between REM time and emotional learning. REM sleep functioning should not be viewed separately from the functions of NREM sleep and the waking state.