Tears, and the Underwood.
Elaine Morgan (Elaine@desco.demon.co.uk)
Tue, 14 Nov 1995 16:15:35 GMT
First, a few observations.
!. Paucity of data. Most accounts of weeping mammals either are, or can
be plausibly dismissed as, anecdotal. Predictably each side accepts the
anecdotes that support it and rejects the ones that don't. This is a
sterile type of argument so for the rest of this debate I propose to
eschew any reasoning based on such accounts.
2. One basic fact seems to have been established. Human psychic tears
are unique among primates, as unique as speech or the decended larynx
or the loss of body hair, and therefore as likely to shed light on the
origin of our species. Attempts to throw doubt on this have been
derisory. If anyone still doubts, it may testable,
Prediction: I predict that in the case of non-human primates, any
anatomist looking for the nerve from the frontal lobe to the lacrimal
nucleus will fail to find it.
3. Salt glands. JDM did a triumphal war dance and for the umtpeenth
time unwarrantably called me a liar when he discovered that salt glands
in sea birds evolved from potassium-excreting glands in land birds.
Whoever said anything different? And it is totally irrelevant. The
whole point about convergent evolution (cf sharks and dolphins) is that
creatures with widely different anatomies move towards similiarities of
form and function - starting from wherever they are and using and
adapting whatever organs they've got.
Now hypotheses.
A. Darwin's. "Cause of the secretion of tears", a chapter in "The
Expression of the Emotions in Man and Animals, University of Chicago
Press, 1965. He says, "There can, I think, be no doubt that the
contraction of muscles round the eye, during violent expiration or when
the expanded chest is forcibly compressed, is, in some manner,
intimately connected with the secretion of tears." (p 167) and "it is
at least possible that the spasmodic contraction of the eyelids, by
pressing strongly on the eyeball, should in a similar manner cause some
secretion", (p 171) He argues that screaming babies (over six weeks)
violently contract the muscles round their eyes, and that in later life
"When with the advancing age of the individual or with the advancing
culture of the race the habit of crying out or screaming is restrained,
it may nevertheless well happen that tears should still be
secreted.".."through habit". That is interesting but I think flawed.
He concedes that often tears of grief are shed with the muscles round
the eyes uncontracted and the brow unfurrowed, and that the elephant
(which he ranks as a fellow-weeper) does not contract its eyes when it
weeps.
B. Ashley Montague's. "Natural Selection and the origin and
evolution of weeping in man" (Science, Vol 130. pp 1572-5). He
attributes weeping to the long dependency period of the human child,
its need to attract attention by (vocal) crying, and the fact that this
noise-making, through the inhalation and exhalation of air, has a
drying effect on the mucous membranes of the nasal passages which
adversely affects their bactericidal properties. Weeping counteracts
this unfortunate result of "dry crying", because some of the lacrimal
lquid,
via the nasolacrimal duct, gets into the nasal passages, I think this
too is interesting but flawed. If as he suggests this was a "trait
acquired not with, but some time after, the assumption of hominid
status" it is hard to see why the most vulnerable period of infancy - the
first six weeks - was left unprotected. And it does not explain why
young chimps, whose vocal yelling and screaming can be very loud and
sustained, have not needed to evolve this safeguard against the drying
of the mucosa.
C. Morgan's theory that psychic tears were once hypotonic and used for
salt excretion. Interesting but flawed (I am in good company so far).
D. Morgan's new theory, that constant exposure of the eyeball to water
would dilute the bactericidal content of tears aand yet would fail to
trigger reflex tears in the way that other deleterious substances do.
Strengthened defences and a new mode of triggering secretion would be
desirable. I still fancy this one, and it may be testable. So for those
who are always clamouring for predictions here is the second in one
post.
Prediction: I predict that the tears of sea otters (whether regarded as
psychic or not) will be found to con=tain a higher percentage of
antibacterial and antiviral substances than the tears of polecats or
other terrestrial mustelids,
E. The signalling theory. I have often been given this explanation
verbally, though I don't know that anyone has written a paper on it.It
is that tears are a signal to alert the mother to the fact that her
baby is unhappy. This requires belief in a female so short-sighted
that she does not notice the great square hole in her screaming baby's
face, and so hard of hearing that she is unaware of the din it is
making, but as soon as the tears flow she thinks to herself
"Dear me, I notice that some water is coming out of its eyes. Perhaps
it wants something."
F. JDM's theory. Unless I have missed it, he hasn't confided in us. He
fills many pages with protests that I am wrong, but not a single
sentence to explain "This is why I think we weep". It joins the long
list of anomalous human features to which the orthodox response is
"Your explanation is wrong. I have no explanation and do not need one.
Perhaps there is no explanation".
Somebody once said that AAH was spreading like a cancer. What seems to
me to be spreading like a cancer is this "can't explain, won't explain"
tendency - defeatism raised to the status of a scientific principle.
The Underwood.
I was highly amused by the vision of Granny Morgan tapping away on her
trusty old Underwood, presumably clad in mittens and a shawl. No. no.
the truth is far more Fred Flintstone than that. All the books and
papers - like the film script which is currently my day job- were
written with a ball point pen.
E-mail on a Samsung. With two fingers admittedly - but who's counting
digits as long as the brain behind them is state-of-the art? Don't do
me any favours and don't count me out. Like Robert Frost,
"I have promises to keep
And miles to go before I sleep." (page ref. on request)
Elaine
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