J.A. Hadfield, in his book Dreams and Nightmares (Pelican 1954), puts forward what he calls a biological theory of dreams. He says the function of dreams is that, by reproducing di...

Jung, Hadfield and several other dream researchers believe the dream process is linked with homoeostasis or self regulation (see Man and His Sym­bols, Jung; Dreams and Nightmares,...

Adaptive theory speculates that species-wide sleep patterns developed as a way of adapting to the environment. Grazing animals, for example, sleep relatively few hours a day in sho...