"Bob Marcus" wrote :
Furthermore, a sighted test always involves several different parts
of
the
brain, because you're using your eyes, as well as your memory of
everything
you have ever heard, read, or thought about the products you are
comparing.
To claim that sighted listening is more sensitive because it involves
fewer
parts of the brain or less mental processing simply runs counter to
the
facts. It is LESS sensitive precisely because it involves MORE
processing
in
MORE parts of the brain.


Mkuller wrote:
This is just plain wrong - how did you arrive at this conclusion?

Harry Lavo wrote:
Would you care to restate that as an opinion or an hypothesis?


Marcus wrote:
No, I would not. Expectation bias is an established fact, Harry.


mkuller
Yes, it is. OK so far.


Marcus
And it
occurs precisely because the brain is simultaneously processing loads of
non-sonic information at the same time that it is trying to come to a
conclusion about the sonic information.


mkuller
That's an interesting conclusion - I would have thought it was due to
listener
*expectations* of two different audible stimuli being different.


Marcus
And those expectations result from the non-sonic information--seeing the
cables, or having formed a prior impression of them. Don't take the word
"expectation" literally, here. It doesn't require a conscious pre-judgment.
Indeed, many people who have consciously "expected" two things to sound the
same have perceived them differently in a listening test (and reported so
here). That doesn't mean they weren't affected by expectation bias. This
bias rears its ugly head subconsicously *during* the listening test.


We're talking about two different audio component comparison tests - one
*sighted* and one *blind*. Unless the subjects are the Who's Tommy (deaf and
blind), they will be processing information from their five senses equally in
BOTH tests - regardless of what anyone has seen or read in the past.

Marcus
I think the best way to understand this is to think of the brain as
synthesizing all of the information it has available to it--what you see,
what you hear, what you've read or heard about the product in the past--at
the time you are conducting the comparison. Most of the time in life,
synthesizing available information is exactly what you want your brain to
do. Listening comparisons may be one of the rare cases where you don't want
that synthesis--you want your brain to respond based solely on what you hear
at that moment.

The only way to do *that* would be to perform the listening test in a sensory
isolation tank.

Alas, the survival of our primate ancestors did not depend
on the ability to isolate information from a single sensory organ, so it
wasn't a skill we developed.


Or one that is relavant to *blind* versus *sighted* listening because the
subject is not really *blind*. Alas?

mkuller
In fact, in a
blind test where nothing is changed, aren't differences usually identified?


Marcus
I'd say "often," not "usually," since I can't say it happens more or less
than 50% of the time. (Tom N. may have better data on this.) Again, this is
expectation bias, based on the non-sonic "knowledge" that something *has*
changed. Your brain has two conflicting pieces of information: the sound,
which we agree is identical from A to B; and the belief that a different
mechanism is making the sound. Not surprisingly, your brain produces
conflicting results in that case. Note that this phenomenon occurs even in
sighted listening, when someone fails to flip a switch. Several people here
have testified to that experience.


My point is - if it occurs at all in *blind* listening, it cannot be because of
sighted cues interferring with the brain's processing - which is what you are
claiming. Geesh.
Regards,
Mike