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Re: Gibson

I agree that any stable, self-consistent pattern is potentially
decipherable, and in this respect, taking movies as a whole, where entirely
'unnatural' jumps, zooms, flashbacks etc., offer no problem to most viewers,
one can see that many such patterns are decipherable even though some major
characteristics are different to the regularities in whose presence we
evolved. So behavoural flexibility is still built on the assumption that the
world will make sense (or can be made sense of).
This in turn rests on an innate assumption that patterns represent
'potential information'. What are we to call this potential information? is
the word 'pattern' appropriate?
If information is entirely epiphenomenal, does this account for the
similarities AND the differences in correspondence with said patterns? In
other words, to say that the similarities between the 'external patterns'
and the 'internal' information is entirely due to a close matching between
patterns and information, such that the percipient has perceived something
close to 'objective reality', and to simultaneously say that differences are
entirely due to internal factors within the percipient ('subjective reality)
seems impoverished as explanation.
----- Original Message -----
From: "Christian Kaernbach" <chris@PSYCHOLOGIE.UNI-LEIPZIG.DE>
Sent: 05 March 2001 08:52
Subject: Re: Gibson

Dear Al,

> I agree that there is a pattern of flow in the light that reaches
> the eyes as we walk forward.  However, until the  brain makes
> sense of this pattern, it is not "about" the world.  It is merely
> "caused by" the world.  These ideas "about" and "caused by" are
> not synonymous.  Everything is caused by something, but if
> everything is information, the word loses its unique meaning.

I wholeheartedly agree with your criticism of the Gibsonian hypothesis.
Let me add a didactical aspect. I start my lecture on perception with a
citation by the famous Gestalt psychologist Wolfgang Metzger, in his
book "Gesetze des Sehens" (i.e. "Laws of Vision", 1st ed. 1936, I think
it is the beginning of his book):
   Dem Menschen, der unbefangen um sich schaut, kommen seine eigenen
   Augen dabei wie eine Art Fenster vor. Öffnet er ihre Vorhänge,
   die Lider, so "ist" da draußen die sichtbare Welt der Dinge
   und der anderen Wesen. Nichts könnte den Verdacht erwecken,
   daß irgendeine der daran erkennbaren Eigenschaften
   ihren Ursprung im Betrachter habe...
now let me try(!) a translation:
   For man, looking around him ingenuously, his own eyes appear
   to be a kind of windows. Opening their blinds, the lids, the
   visible world of things and other beings "is" outside. Nothing
   could raise suspicion, that anyone of the discernible properties
   of the world would have their origin in the viewer...
I cite this because I want students to overcome the naive concept of
perception ("What does cause your perception that this shoe is red?"
"Why, it is red, isn't it?"). The Gibsonian use of the word "meaning"
would make it incredibly hard to avoid having my students fall back to
this naive view. I am sure the Gibsonian view can be stated such that
the difference could finally be understood. I am not sure whether this
would hold for all of my students. I don't teach Gibson.

Your movie example deserves further consideration. If the pixel
permutation were done in a retina-stable way, the brain would probably
be able to adapt to this permutation after some days or weeks. Consider
the famous experiments by Helmholtz with prism glasses and follow-up
studies with 180° turn-around glasses which showed the enormous
flexibility of the brain to adapt to optical transformations. The
ability to make sense of the permuted movie proves that something _is_
in the outside world. I would call it physics, not meaning...

- Christian

> Another example: Suppose there were a device that took a
> pixelized photo, A, and mapped each point in it onto an output
> photo, B.  If the mapping were:
> Y (i,j) = X (i,j)
> then the output photo would be a copy of the input.  Suppose,
> instead, that we used a random, but fixed, function to do the
> mapping such that, for example,
> Y (1,1) = X (14, 201)
> Y(1,2) = X (3113, 21)

Dr. Christian Kaernbach
Institut fuer Allgemeine Psychologie
Universitaet Leipzig
Seeburgstr. 14-20     Tel.: +49 341 97-35968
04 103 Leipzig        Fax:  +49 341 97-35969
Germany               http://www.kaernbach.de/