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From: clw%tornado.Berkeley.EDU@ucbvax.Berkeley.EDU (A Ghost in the Machine)
Newsgroups: sci.virtual-worlds
Subject: Re: Reading text in virtual reality?
Message-ID: <1990Aug20.194453.26319@agate.berkeley.edu>
Date: 20 Aug 90 19:44:53 GMT
References: <25797@cs.yale.edu> <1990Aug16.134553.29297@zorch.SF-Bay.ORG>
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In article <1990Aug16.134553.29297@zorch.SF-Bay.ORG> xanthian@zorch.SF-Bay.ORG (Kent Paul Dolan) writes:
>
>This brought to mind another human ability, nearly magic, that will be
>of _crucial_ experience for navigating virtual reality, and that seems
>to have been neglected as yet.  This is the "cocktail party" phenomenon:
>in a crowd of fifty conversations, our ears can somehow pick out the
>one of interest to us, and focus on it to the exclusion of all others.


	It is my understanding that this ability stems mostly from auditory
preprocessing in the brain:  the signals from both ears are compared 
(experiments show that relative amplitude, phase, and possibly timing
are taken into account), and sounds are sorted according to location.  The
shape of the ear eliminates front-to-back symmetry (again, an experimental
result).
	Thus it turns out that much of this ability is lost if the sensitivity
balance between ears changes (i.e. partial loss in one ear), even if the
actual hearing loss is quite small.  People with such minor hearing damage
do very poorly picking voices out of crowds or in noisy backgrounds, despite
having reasonably acute hearing.
	An excellent example is to sit in a room of several conversations,
and tape it with a single mike.  Later, try to pick out what each person
was saying from the monaural tape (not just the loudest, all of them).
That's what it would be like without binaural hardware and a dedicated 
preprocessor.

	clw