The Dreams of Children and of Animals

Children do not dream as adults do, and did not, it turns out, dream much at all before five. Foulkes (1982, 1999) brought children to the laboratory at Wyoming for nine nights every other year across five years and woke them from REM: at three to five they reported a dream on 17 per cent of awakenings, in a few words, static, without a self in them, “a chicken eating corn”; by seven to nine the rate was 43 per cent, with movement, a narrative, and the child as actor; and only by eleven did the dreams reach adult length and complexity. The development tracked not language or memory but the child’s visuospatial ability on the block-design test, as if the dream were a construction the child had to learn to make.

The nightmares of childhood, which parents hear about, peak between five and ten and concern animals and monsters; the night terrors, which the child does not remember, come from deep sleep in the first hours. Recall rises through adolescence and falls through adult life, with the old reporting fewer, shorter, and less emotional dreams; the Hall and Van de Castle norms are from twenty-year-olds, and the Journal’s comparison should be read with that in mind.

Whether animals dream cannot be asked, and the laboratory has come as near as it can. Every mammal and bird studied has REM sleep; Jouvet’s cats with the paralysis circuit cut stalked invisible prey in theirs; Wilson and McNaughton’s rats replayed the maze in slow-wave sleep and, in Louie and Wilson (2001), in REM too, at the speed of waking; and Dave and Margoliash (2000) found the zebra finch rehearsing its song in its sleep, neuron by neuron, in the order of the notes. The platypus has more REM than any animal measured; the dolphin, which sleeps one hemisphere at a time, has almost none.

The dog that twitches and runs in its sleep is, on this evidence, doing what the cat did: its brain is in REM, its motor cortex is sending the commands, and the paralysis is leaking. Whether there is anyone home to see the dream is the question that the hard problem leaves for everyone, and the dog cannot keep a journal.

Sources

• Foulkes, D. (1982). Children’s Dreams: Longitudinal Studies. Wiley.
• Foulkes, D. (1999). Children’s Dreaming and the Development of Consciousness. Harvard.
• Louie, K., and Wilson, M. A. (2001). “Temporally structured replay of awake hippocampal ensemble activity during rapid eye movement sleep.” Neuron 29.
• Dave, A. S., and Margoliash, D. (2000). “Song replay during sleep and computational rules for sensorimotor vocal learning.” Science 290.
• Siegel, J. M. (2005). “Clues to the functions of mammalian sleep.” Nature 437.

A review of the literature for readers; not medical advice.