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Brains: Man vs.Chimp

suzanne smith suzannes at vir.com
Tue Jul 25 21:31:06 EST 1995

> : Similarly, although it does not have to do so much with innate
> : anatomical differences but rather with the upbringing, chimps are
> : less likely (although I don't have references for you) to confuse
> : the size of two lengths as humans do when the "arrows" at the tip
> : of the line point in different directions.  I.e. we would say
> : that line A is shorter than B whereas a chimp would not:
> :                    >------<    line A
> :  
> :                    <------>    line B
> I think you are wrong here. If you have a reference, I would like
> to see it.  We are about to use a similar "compelling" optical
> ilusion on a rhesus monkey.

I base this argument on what I recall was the explanation for
the illusion.  That is, since we, in the industrial world, live
in buildings where the rooms are basically cuboidal, any inside corner
of any room looks like this:

..whereas every outside corner looks like the opposite (arrows pointing
the other way).

Since we associate the first with things that are far, we "know" that
they are really bigger than they seem.  Hence our mind distorts the
true size as seen.

When the arrows point the other way, we know that we are really close
to the wall corner and that what we see is more accurate (less distortion
in the perception).

To add weight to the interpretation as I have so awkwardly tried to 
summarize above, the author (or lecturer) said that these illusions did
not work on people who live in huts or other non-rectangular rooms.

What information do you have on this?  I'd be interested in knowing.
I also recall that primates have an "innate" tendency to dislike
sinusoidal lines -- which translates to an innate prejudism to snake-
like creatures.  Do you have any information on this?


rbourgeois at dawsoncollege.qc.ca

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