Sleep takes up around a third of our lives, and is an object of fascination during the other two thirds. "I dreamt that..." is surely among the top 10 conversation topics of all time.
Given this, it is surprising how little attention is paid to the anthropology
of sleep. Intriguing (but too little) work has been done on sleep practices in
We condense our sleep into a single lengthy stint, in which any interruption
is considered to be a pathology, while our forebears and preindustrialized societies
enjoy segmented sleep. They also display a fuzzy "continuum of
arousal...from...disengaged semialert, to somnolence or drowsing, to dozing, to
We sleep alone from an early age and do everything possible to minimize sensory stimulation and isolate ourselves from the external environment. Perhaps this helps explain why the same poll found that "one-third of Americans are losing sleep over the state of the US economy and other personal financial concerns." Other cultures tend towards "multiple and multiage sleeping partners; frequent proximity of animals; embeddedness of sleep in ongoing social interaction; fluid bedtimes and wake times; use of nighttime for ritual, sociality, and information exchange; and relatively exposed sleeping locations that require fire maintenance and sustained vigilance." I feel that I'm missing out on the richness of the experience.
On first reading of the two features on sleep in this issue, I was skeptical of the use of rats and mice as good behavioral models of what I presumed to be the standard human sleep behavior. But the sociality, polyphasy, and gradations in alertness in rodents seem rather similar to that described in most humans, making extrapolations more comfortable.
In "Disappearing before dawn", freelance writer Kelly Rae Chi focuses on the crystallization of sensory information into memory. The traditional view is that memories are replayed during sleep, strengthening the appropriate circuitry. Researchers Chiara Cirelli and Giulio Tononi have turned this idea on its head, proposing instead that during sleep, synapses become weakened. The end result of both processes—the predominance of select circuits—is the same, but whether it is arrived at by the enhancement of particular synapses or the weakening of all but the strongest is a big deal.
The author of the second feature, Alan Pack, has demonstrated the possible
ancient origins of sleep in the sleep-like state found in C. elegans.
This is associated with molting,