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Re: Pre-echo audibility AND backward masking

Dear Soren

Thanks for your response.  I am a doctoral student and interested in
phenomena associated with the temporal delay between auditory stimuli,
primarily in relation to brain electrical activity (ERPs). I'm not familiar
with echo studies but this is obviously interesting for me.

In regard to pre-echo audibility, I wonder if loudness enhancement might not
play a role here. That is,  detection thresholds for the first sound may be
lower BUT only relative to the threshold for the second sound, which is
higher due to loudness enhancement?  There are a couple of papers describing
loudness enhancement if you think it's relevant:
Zwislocki et al 1974 Percept. Psychophys 16: 87-90;& 91-95. Zwislocki et al
1959 J. Acoustic.  Soc. Am. 34 9-14.  Efron is another author who has done
some relevant work.

Loudness enhancement is often interpreted in terms of the temporal summation
of acoustic energy of two closely spaced sounds...by the brain not the ear.
This is what I'm interested in in relation to backward recognition masking
"BRM".... which is different from backward detection masking "BDM" in that
subjects are asked to make a judgment about the the pitch or intensity of
the probe not simply detecting it as is  the case for BDM. This may then be
relevant to your original question as although BRM experiments typically use
a masking tone that is physically different from the probe as is the case in
BDM (usually longer duration only), I have found (and maybe others as well)
that BRM paradigms can produce masking when the probe and mask are identical.

Essentially I'm  wondering whether BRM effects may be relevant to the echo
phenomenon  as well.

There are some good reviews of theoretical an empirical information relevant
to BRM and BDM which relate to processes such as temporal summation,
auditory persistence, echoic memory etc. from authors like  Nelson Cowan,
Dominic Massaro which may be interesting to you.

I would appreciate any references or information you have (or any list
members) that discuss  physical similarity between  the probe and mask and
how this relates to probe detection (or recognition) thresholds.



At 08:55 AM 6/01/97 +0100, you wrote:
>Dear Bill,
>Thanks for your mail.
>I'm sure you are familiar with usual Post-echo where a sound is followed by a
>delayed and attenuated copy of itself. This happens, for instance, if you shout
>in a long corridor.
>Pre-echo is the opposite phenomena where the first occurence of the sound is
>weaker than the delayed. This does not happen in natural "passive" surroundings
>but can be created electronically. I think the effect was first noted as
>pre-print-through on magnetic audio tapes that had been stored on the wrong
>Please get back to me if you have any information on the audibility of such
>Soren Laugesen
>Oticon A/S
>Research Centre, Eriksholm
>DK-3070 Snekkersten

   Bill Budd
   Cognitive Neuroscience Laboratory,
   Department of Psychology,
   University of Western Australia,        \  ?  /
   Nedlands.  6009.                                     |

   Phone: 09 380 3468
   Fax: 09 380 1006
   Email: bill@psy.uwa.edu.au