Re: Implicit human echolocation

[Peter Lennox <P.Lennox@xxxxxxxxxxx>]

Barry,
I'm confused, though suspect the confusion lies in the way we each use
the word "perception" - you state that echolocation is more than 'just'
perception, and I'm not sure what you mean. This may be, though, because
I haven't found anything that humans do that isn't perception. In other
words, for me, cognition is part of perception, rather than being
subserved by perception. so in this context, something one 'knows'
through being steeped in a culture is simply one kind of perception,
rather than a qualitatively different activity.
In other words, for me, perception isn't too closely identified with
sensation - it's not just 'sense-perception'.
Am I using the term radically differently from others' usage?
regards
ppl

Dr. Peter Lennox
S.P.A.R.G.
Signal Processing Applications Research Group
University of Derby
http://sparg.derby.ac.uk  
Int. tel: 3155
>>> Barry Blesser <bblesser@xxxxxxxxxxxx> 05/31/07 10:28 PM >>>
Hi,

Having followed the dialog on human echolocation, I would like to
introduce
an alternative (contrary) perspective on the subject.

There are many reports over the centuries describing people doing
echolocation. Diderot, the French philosopher, first observed this in
the
18th century. In the 1930s it was  called face vision. Following WWII,
echolocation among those with a visual disability was a hot and
confrontational topic. There is an extensive literature on the subject.
Clearly, some human being can use this ability to "see" with their ears.
When I was teaching at MIT in the 1960s, I often demonstrated the effect
by
having a random student walk slowly towards a wall with eyes closed and
instructed to stop 6" before hitting the wall. Almost everyone could do
it
on the first try, and everyone could to do it after several attempts. At
least that was true in the acoustics of the older MIT classrooms (dating
from the early 20th century and highly reverberant).

This raises the question of what are people doing? I am confident that
everyone can "hear" the required physical cues. If one recorded the
background noise at the center of a hall and also close to the wall
surface,
I believe that everyone would perform very well in an ABX or
same-different
paradigm. Detecting (discriminating) auditory cues is only part of the
story. The second part is for the listener to create (invent) a
cognitive
strategy that transforms perceptible cues into a physical reality, in
this
case, proximity to the wall. To do echolocation in a real setting, a
listen
must have a cognitive strategy. And that strategy could have been
created
years ago or only during the experiment. Some blind individual have
evolved
an elegant strategy, as explained by Dan Kish, the blind teacher of
orientation and mobility. But other blind individual who are taught to
use
the cane never learned to use hearing for navigation. They may not have
a
strategy.

My objection to the proposed research is the issue of what question is
being
asked and then answered. If the central issue is a cognitive strategy,
which
involved labeling, pattern recognition, and auditory memory, then the
experiment only reveals who has, and who has not, created such a
strategy.
The answer is dependent on life style, personality, local culture,
sensory
attitudes, intellectual curiosity, and so on. I have no doubt that some
people do not know that such a strategy could exist. Others may know
that it
exists but never attended to it. In my case, I have a self-taught but
primitive strategy. Strictly speaking, echolocation is far more than a
perceptual issue.

When I examined this subject while researching for my book, Spaces
Speak,
Are You Listening, discussed mostly in Chapter 2 and extensive
references, I
came to the conclusion, that we need to introduce the concept of
cultural
acoustics, which is of course difficult to study and seldom
reproducible.
But this limitation does not make the phenomenon any less real. If we
only
study questions that match our convenient (scientific) paradigms, then
we
are distorting the phenomenon with an intellectual dishonesty. There is
no
evidence that echolocation is only a perceptual ability.

And that is my two sense,
Barry


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