prosopagnosia illustration

j.adelman at ukonline.co.uk j.adelman at ukonline.co.uk
Fri Apr 13 16:18:19 EST 2001


A few things come to mind which suggest that an explanation based on lack of
exposure at a time when face-recognition is developing is incomplete.

(i) Children have a preference for faces over less face-like stimuli from
birth.
(ii) Preference and discrimination of particular faces occurs very early in
life; how can we recognise new people after this point?  Faces aren't like
lines, because they are various, not elementary.  
(iii) Face perception appears to be able to develop later in life; this is
suggested by, for example, dog experts whose face recognition for dogs have
features very similar to that shown by most people to human faces.  This, to
me, seems to suggest that value is very important, since top-down processes
would operate to prevent the processing of some kinds of face information.  


In sci.cognitive Jack Barnhardt <jackeb at earthlink.net> wrote:
> I agree with the last paragraph, but I don't quite understand how it is
> compatible with an earlier statement in your posting where you say that the
> inability the distinguish certain faces is not a biological phenomenon.
> The way I see it, what you describe in the last paragraph is precisely a
> biological phenomenon.

> Developing the ability to distinguish human faces through exposure to these
> faces is probably no different than developing the ability to percieve more
> simple shapes or even the most basic visual stimulus:  a border or line.
> If one is not exposed to vertical lines when the visual system is
> developing, one will not be able to percieve vertical lines later.  The
> tissue that would normally mediate this perception will become devoted to
> other things.

> In other words, being deprived of exposure to stimuli can result in an
> inability to percieve or distinguish it.  (This concept is certainly not
> limited to vision.)

> This seems like a much more reasonable explanation than the 'racism'
> hypothesis (and I'm happy you disagreed with it).

> Cultural influences affect our experience, and therefore affect the
> developement of our nervous system.

-- 
James S. Adelman




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