From newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.csri.toronto.edu!rpi!usc!cs.utexas.edu!uunet!tdatirv!sarima Tue Jan 21 09:26:54 EST 1992
Article 2860 of comp.ai.philosophy:
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>From: sarima@tdatirv.UUCP (Stanley Friesen)
Newsgroups: comp.ai.philosophy
Subject: Re: Waking up is hard to do, but somebody's got to do it
Message-ID: <382@tdatirv.UUCP>
Date: 17 Jan 92 19:57:39 GMT
References: <60551@netnews.upenn.edu> <334@tdatirv.UUCP> <60759@netnews.upenn.edu> <350@tdatirv.UUCP> <61668@netnews.upenn.edu> <363@tdatirv.UUCP> <61968@netnews.upenn.edu> <370@tdatirv.UUCP> <62373@netnews.upenn.edu>
Reply-To: sarima@tdatirv.UUCP (Stanley Friesen)
Organization: Teradata Corp., Irvine
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In article <62373@netnews.upenn.edu> weemba@libra.wistar.upenn.edu (Matthew P Wiener) writes:
|In article <370@tdatirv.UUCP>, sarima@tdatirv (Stanley Friesen) writes:
|>				  My own body certainly *seems* to recover
|>from exertion and stress faster if I sleep than if I do not.
|
|Oh yes, lots of circadian and/or daylight correlations are known.  Yet
|sleep deprivation leads to one clear cut result in the short result:
|heavy mental confusion.

It seems to go beyond circadian/daylight correlations.  If I am in a
seriously depleted state (ill, or short on sleep) I get the same effects
by sleeping out of my normal time slot.

This is paritcularly true of illness, where sleep seems to help recovery.

|I agree.  Sleep could have more than one function.  Or it could have
|evolved to have more than one function.  To distinguish these, I ask
|the question: why should PM require the turning off of consciousness?

Because the PM covers mental as well as physical PM. And becuase some of
the machinery that is being rebuilt is the machinery that sustains
consciousness.  You cannot change the CPU board on a computer and expect
it to continue running right through.  And fsck can only be run on unmounted
disk partitions.  A complete fsck thus requires all normal activity be stopped.
And transfering files to 'backing store' while they are being dynamically
updated is a sure recipe for corrupted or inconsistant files. So the memory
update functions of REM sleep (well established experimentally) are certainly
likely to require reduced, or suspended, consciousness.

|If you say it's a side effect of turning bodily activity off, to allow
|PM to proceed, consider the dolphin, which half-sleeps, and does not
|get any bodily rest.

I think this last statement is too strong.  Just because dolphins continue
to move all of the time does *not* necessarily imply that they are not
getting any bodily rest.  All that is necessary is for bodily functions to
be turned down to minimum sustenance levels, with the excess resources so
released going to rebuilding or reparing worn out subsystems.

This seems to be a general trait if aquatic animals, they shut the various
subsystems asynchronously, rather than synchronously like land animals.

This is rather like PM in fail-safe systems, where you can take down one
(or more) of the redundent units without bringing the whole system down.

|>|Who knows?  Reptiles don't have REM sleep.  Very few mammal species
|>|(dolphins, spiny anteaters, ????) don't.
|
|>Dolphins *don't* have REM sleep?  That really plays havoc with sleep as
|>a quantum result of brain activity.  Dolphins are the closest thing amoung
|>non-human animals to a conscious being.
|
|It would play havoc if we knew more about dolphin sleep, and what their
|circadian rhythms were like and so on.  As I pointed out above, the dolphin
|plays as much havoc with your view too.

I am not convinced, since I doubt your conclusion above.

Either way, the dolphins do become an important factor in the analysis.
More research is clearly indicated.

But the *extremely* high level of intelligence in dolphins is of great
importance, and must be consistant with *any* theory of sleep for it to
be viable.

|>|I refer to an active self-awareness to get food--tastes good!--rather than 
|>|stop the stomach from growling--less filling!
|
|>But, I think that it is very questionable to assume that animals *don't*
|>eat because it tastes good (in part).  Certainly my sister's pet dog seems
|>to have some very definate ideas about taste, and what she (the dog) likes.
|
|Good grief.  Pet dogs are pampered--they learn to be finicky. 

True, Caluah is not exactly normal, not even for a domestic dog.
But domestic dogs have no intrinsic mental capabilities that wild wolves
do not.  And wolves do grow up in packs with much social interaction.
There is *no* question about the fact that wolves *learn* much of their
behavior in the wild.

There is also plenty of evidence for selectivity, even learned selectivity,
amoung wild animals.  Birds are known to get drunk on naturally fermenting
berries; raccoons search diligently for preferred foods; and so on.

|>|You'll also note that predators like lions generally sleep more than their
|>|typical prey like zebras.  They eat their fill and laze around for days at
|>|a time.
|
|>Yep, because meat is a much more concentrated source of energy, so less
|>is needed.  Thus the zebra *must* spend most of its time eating, while the
|>lion simply does not have to do anywhere near as much.  Given a relatively
|>safe place to sleep (the middle of a pride with guards posted), one might
|>as well sleep when there is nothing else to do.  I certainly tend to.
|
|The above is at best an ad hoc explanation.  You can do this for any
|correlation I mention.  My friend Occam likes the unified explanation:
|sleep is needed for consciousness/intelligence.

But mine is also unified. Sleep helps maintain the body.  When there is nothing
else to do, maintenance is as good a way of using energy as any other, perhaps
better.  Energy budgeting is a *primary* concern of many evolutionary
adaptions, from reproductive strategies to apparent cases of inheritance
of acquired characteristics.  Why should sleep be exempt from this, high
priority, aspect of evolution?  (Only raw reproduction takes clear precedence).

|>|This is known?  Considering how varied dolphin sleep is from other mammals,
|>|or even human from shrew, I find it quite difficult to buy the above based
|>|on extrapolation from today's patterns.  Is there some other determination?
|
|>Yes this is known.  It is based on comparative anatomy and taxonomic
|>relationships.  Nocturnal animals have identifiable anatomical features
|>that show up in fossils (such as large eyes, which are preserved as large
|>eye sockets).
|
|My memory of therapsids doesn't include eyes larger than the dinosaurs.

Hmm, I was not talking about therapsids.  I was talking about Mesozoic
mammals.  (Diconodonts, Triconodints, Symmetrodonts, Pantotheres,
Multituberculates, Leptictid placentals, and so forth).  By the time
dinosaurs became common the therapsids were all but extinct  (one small
group of very mammal-like forms did survive into the earliest Jurassic).

|I'll look it up.  Opossums don't have particularly large eyes, although
|yes, they are nocturnal and ancient.  (Is there some meaning of "large"
|running around that I'm not familiar with?  Could be.  The really large
|eyes, like on an owl, are perhaps there for seeing prey from a distance.)

Hmm, well, large is a relative term.  It is measured as a ratio of eye-ball
diameter to some other standard measure (or in the abscence of an eye-ball,
the ey-socket is used).  I believe that the standard base measure may be height
of the brain case or some such thing, but I do not rememeber for certain.

Once you have this relativized measure you perform a discriminant analyisis
on the data set.  This generates a decision function that can be applied
to fossil mammals.  (It does have an 'indeterminate' region in the middle
where the eye size is consitant with both interpretations - but few mammals
either living or extinct fall in this zone).

|>	        Also it is possible to derive an evolutionary tree of the
|>vaious groups of mammals, and they generally trace back to nocturnal ancestral
|>forms.
|
|This is the part I'm suspicious of: sleep has evolved to some pretty weird
|patterns that I don't like continuity of sleep style assumptions.  That
|sleep will be there in some form or other I believe, but it will adapt
|to the niche the animal finds itself in.

There is no real continuity assumption here.  Have you read up on cladistic
analysis?  It is able to derive probably ancestral states even where the
characters are discontinuous (actually it works *better* on discontinuous
states - but you will never get most practitioners to admit that).

Roughly speaking, and skipping alot of debate and analysis, the mode of life
common to living shrews, opossums, tree shrews, bats, and prosimians is likely
to be the ancestral state for all living mammals.

[P.S. I am *not* a cladist, but I do believe that thier methods are useful
for certain limited purposes].

|>|>There is a problem here. Almost all Cretaceous mammals were *nocturnal*,
|>|>sleeping, if at all, during the *day*, when the dinosaurs *were* active.
|
|Are you implying early mammals did not sleep?  Because of the incredible
|dangers of predatory dinosaurs?

No, just your prior argument (whatever it was) is not applicable.
I think that nocturnal Mesozoic mammals *did* sleep, by hiding in little
holes where dinosaurs couldn't get them.  That is why they never grew
very large until *after* the dinosaurs were gone and they no longer
had such a strong incentive to hide during the day.

|>No.  But sleep does not fossilize, so we do *not* know if they slept in any
|>direct way.  I tend to assume they did, since all living mammals do, but that
|>is only a reasonable conclusion, not a fact.  Of course, I do find it hard to
|>imagine what a nocturnal animal would be doing during the day if not sleeping!
|
|I too.  Which is why I think your view of the danger aspect is exaggerated.

No, the danger aspect does not really come in.  The early mammals were all
so small that they could hide very easily.  The *largest* was small cat-sized,
and that was only in the very latest Cretaceous.

|>						 (Of course the carnivorous
|>dinosaurs that were even more closely related to birds *were* rather
|>intelligent - the most intelligent forms almost reaching avian levels of
|>intelligence, but certainly not mammliam levels).
|
|And these were the ones that early mammals had to avoid.  The ones that I'm
|presuming did the most sleeping/estivation then.

Quite, by crawling into holes, just like similarly sized mammals do today.

The smallest known carnivorous dinosaurs were the size of chickens, rather
larger than any contemporaneous mammal.  Most were much larger than this.
The most intelligent of the carnivorous dinosaurs, the stenonychosaurs,
were also *nocturnal* (based on eye size), and they had stereoscopic vision,
otherwise very rare amoung dinosaurs.  The most popular theory is that these
late Cretaceous dinosaurs were specialist mammal hunters. [Hunting at night
when the mammals came out of hiding to forage].

[The only other dinosaur I know of with stereo vision is Tyrannosaurus rex].

|>This seems to be almost to trivialize your hypothesis.
|
|It's nothing more than taking the question "why we sleep" at its most
|obvious.  ...
|Put it on a continuum.
|
|>I might accept that a shrew is conscious, but a dogfish?
|
|So give the dogfish an ultralow primitive consciousness.  So low that
|calling it conscious--unqualified--is ridiculous.

The problem is that then they should also barely sleep.  I am not sure this
is actually true.  [I am not sure it is false either - this merely becomes
one of the predictions of your theory which needs to be checked].

|>It might also be interesting to do a genetic assay of the lesioned
|>tissues to see if they might be suffering from high mutation levels.
|
|And to do the experiment twice more: once heavily shielded and once
|at high altitude.  If you're right, the former should live longer and
|the latter should die sooner.

Actually it depends on the source of the mutagenicity.  If it is from
radiation then yes, but if it is from mutagenic toxins, then no.

[And the symptoms of mutagenic toxins can be quite similar to radiation,
but without the symptoms of *burning* that hard radiation produces].
-- 
---------------
uunet!tdatirv!sarima				(Stanley Friesen)



