"Robert J. Bradbury" <firstname.lastname@example.org> writes:
> I did read a recent article about the fact that anthropologists
> are now starting to study sleep in "primitive" cultures and
> are finding that the traditional Western 8-hours a night
> *is not* a "normal" sleep pattern. More normal is to sleep
> whenever you feel the need to do so, wherever you feel
> like it, taking into account the need for safety, perhaps
> sleeping in "sub-groups" (some sleep, while others watch).
The monophasic sleep cycle is likely (I'm guessing here, but I think I'm right) the result of the industrial age, where you had to work all day. In agricultural societies there is not much need for that, and a siesta makes a lot of sense. Sleeping in the night was however required simply by the lack/expense of light. These days we are likely wrecking our sleep cycles just by having too much artificial light around us (which of course can be a good thing when trying to control them).
> I concur with his comments on the primary purpose of sleep
> being to "integrate" critical experiences into your knowledge
> database. There may also be a biological purpose for
> maintenance, repair & recycling to be done when resources
> (esp. energy) are less needed for "thinking" (though I can't
> point to much hard biological evidence for this).
There are a lot of hormones peaking during the late night, and I think I have seen some claims for increased immune activity (I have some weak personal anecdotal support for this, as I can usually beat most colds just by sleeping long). The experiments of REM deprivation done without stimulants showed that the cause of death was some kind of profound disruption of homeostasis and immune response, if I remember right.
> There is a piece of urban folklore that I put together from a
> number of sources -- Eastern mystics, gurus, etc. apparently
> need very little sleep (2-3 hours a night), while sociopaths
> confined to mental institutions sleep much more (12+ hours
> a day). Now, one would argue that the difference between these
> indviduals is their "closeness" to reality. The mystic really
> "sees" reality and accepts it completely. The sociopath has
> an internal "reality" that is much different from that which
> actually exists externally. If this is accurate, the sociopath needs
> much more sleep (processing time) to attempt to bend/integrate
> actual reality to his internal view of it while the mystic
> needs very little.
Interesting theory. I don't know how well it fits the facts, but it should be possible to check. I didn't find much in medline:
Percept Mot Skills 1980 Dec;51(3 Pt 1):715-22
REM sleep and EEG abnormalities in criminal psychopaths.
Salley RD, Khanna P, Byrum W, Hutt LD
Hare's (1970) REM deficit theory in psychopathy was investigated. The repeated finding of EEG slowing in waking psychopaths has been interpreted as reflecting cortical immaturity, cortical underarousal, and an intense need for sensory stimulation of psychopaths. REM sleep has been implicated in cortical maturation during development and in daily cortical maintenance. Hare postulated a possible REM deficit in psychopaths to account for their apparent cortical abnormalities. Three groups of incarcerated criminals were investigated: psychopaths with normal waking EEGs (n = 8), psychopaths with abnormal EEGs (n = 9), and nonpsychopaths with normal EEGs (n = 6). The sleep stages of each inmate were recorded for one baseline and two experimental nights. No significant differences were found in the sleep patterns of these groups using stepwise, multiple discriminant analysis. The psychopaths with abnormal EEGs tended to have the highest REM time and REM% of the inmates, contrary to Hare's theory.
[Don't know if they measured sleep length.]
J Clin Psychol 1977 Jan;33(1):263-9
Psychotherapists' descriptions of emotionally disturbed adolescent poor and good sleepers.
Monroe LJ, Marks PA
A sample of 53 poor sleepers (N = 37 boys and 16 girls) and a matched sample of 53 good sleepers were selected from a national study of 831 white, emotionally disturbed adolescents in treatment. Psychotherapists' ratings on 552 variables were examined by comparing the endorsement rates of the two groups by means of a split-sample procedure. The results yielded 74 replicated characteristics that differentiate poor from good sleepers, a number of which are highly unique to each group. Poor sleepers are consistently higher on measures associated with neuroticism, whereas good sleepers are higher on measures associated with pseudo-normalcy or psychopathy. These results present further evidence that personality dynamics play a critical role in disturbed sleep. The authors suggest that a reorientation that integrates personality and physiological findings is necessary to advance our understanding and treatment effectiveness of persons with disturbed sleep.
> So if you want to sleep less, you have to minimize the
> differences between the external reality and internal reality.
> Whether you choose to modify the external reality (minimizing
> perceived threats, making it more like your "ideal", etc.)
> or your internal reality (stop worrying about things you
> can't change, "delete" unsupportive thoughts or behaviors,
> etc.) probably depends a lot on your individual situation.
Seems like a good idea whether or not you sleep more or less due to it.
> However, once you have minimized this differences and life
> is very "comfortable", I think some people would want to
> sleep more. The energy costs of controling the internal
> reality completely (in sleep) are much lower than those
> required for controlling the external reality (where you
> have to push matter around), so you can experience more if
> you do it entirely internally.
On the other hand, you can likely experience more flow by having a challenging task in the real world.
I just found this in Medline, which fits in with your idea:
Brain Res Bull 1998 Jul 1;46(4):269-79
Vertebrates that never sleep: implications for sleep's basic function.
University of California, Department of Biology, Los Angeles 90095-1606, USA. email@example.com
A major activity of the brain of most vertebrates during waking behavior is the processing of sensory information, preponderantly visual. This processing is not fully compatible with the brain's spontaneous oscillatory activity that maintains (refreshes) infrequently used circuits that store inherited and experiential information (memories). Great reduction in sensory input and processing during sleep permits the refreshment of memory circuits to occur unimpededly. Accordingly, sleep may have evolved as ever augmenting needs for processing visual information during waking behavior by brains of great complexity conflicted increasingly with needs to refresh memory circuits. The lack of a need for sleep by genetically blind fishes that live in caves, and sighted fishes that swim continuously, is consistent with this thesis, as their needs for processing of sensory information, predominantly visual, are either greatly reduced or nil. Reduced requirements for processing sensory information by continuously swimming fishes owe to the following aspects of their behavior and ecology: (1) visual input is greatly reduced or absent during lengthy periods of nocturnal activity; (2) schooling greatly reduces needs for sensory information, particularly visual; (3) being maintained through frequent use, circuitry for most inherited memories needs no refreshment; and (4) inasmuch as they lead a comparatively routine existence in essentially featureless, open waters, pelagic species acquire, and have need to refresh, relatively few experiential memories. Analogous circumstances could account for the ability of migrating birds to fly for days without rest or sleep.
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