From: waynebro@juliet.caltech.edu (Broughton, Wayne Jeremy)
Newsgroups: talk.origins
Subject: Re: Side-effects or defense m
Date: 1 Oct 1992 17:43 PST
Organization: California Institute of Technology
Distribution: world
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In article <JBy-CBA@engin.umich.edu>, ingles@engin.umich.edu (Ray Ingles) writes...
>In article <5737.170.uupcb@ssr.com> jani.patokallio%acc1bbs@ssr.com (Jani Patokallio)  writes:
>>-> 1.  Motion sickness.  I'm sure there have been
>>-> more cases of this in the past 100 years than
>>-> there has been in the entire history of homo
>>-> sapiens prior to that.  Is there any evolutionary
>>-> need for this reaction?
>>
>>No, it's just a reaction that was simply quite rare before the advent of
>>technology that allowed fast movement.  Motion sickness is caused by
>>the disturbance of the balance of the fluid in the semicircular canals of
>>the ear (I think).
> 
> Pretty sure that's right.
> 
>>-> 2.  Many people feel edgy at the sound of finger-
>>-> nails scraping down a blackboard or a fork scraping
>>-> across a plate.  I doubt early man would have had
>>-> much chance to encounter these sort of stimuli.
>>-> Could there be a reason for this trait to have 
>>-> evolved?
>>
>>Same as above, it hasn't evolved in 100 years.  It's just a trait that
>>wasn't noticeable until the invention of blackboards.  Humans have
>>an aversion to audible high-frequency sounds including but not limited to
>>nails scraping down a blackboard.
> 
> Actually, I heard that the frequencies in something like 'nails scraping
>on a blackboard' are remarkably similar to the distress/alarm calls of
>our chimpanzee cousins. I.e. we have a natural edginess around primate
>distress calls, which is triggered by high-frequency sounds in the right
>range.

I don't know much more biology than said chimpanzee cousins, but I
thought I would pester you with my ideas anyway.  I kind of object 
to the frequent assumption that every trait (including those above
and subtle human behaviours) must have adaptive significance.  Our
bodies and minds (especially the latter) have evolved to be highly
adaptable, but new environments, like (high tech) civilization, can
present entirely unforeseen stimuli to us.  There doesn't have to
be a _reason_ for the nature of our responses to these stimuli, other
than that just happens to be the way our physical and psychological
systems (designed for different circumstances) react under new
circumstances.  I suspect religion (and scientific inquiry) are
just ways people's minds have reacted to the unusual environment of
civilization, for example.  The drugs a patient of chemo-therapy is
taking may cause hair loss, but that doesn't mean that that trait
is an evolved response with adaptive significance.

I guess everybody knows all this, but I still get the impression that
there is an attitude that things must almost always be explained in
adaptive terms.  eg. the old problem of altruism.  Many people talk
about the possible adaptive usefulness of it, especially to close
relatives, but I wonder if maybe a lot of it is just the way our minds
happen to operate in highly organized societies??  Does anyone really
think there are genes coding for the desire to be charitable to the
poor and hungry?  Couldn't this just be the way our mind extends
more basic feelings that do have adaptive significance (eg. altruism
to our close relatives)?

Still yet more of my two bits.

**********************************************************************

Wayne J. Broughton                 Take the road less travelled by.  
waynebro@juliet.caltech.edu    
Department of Mathematics,
Caltech, Pasadena, CA  91125

Caltech has no idea what my opinions are;  
they think I'm working right now...