[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Effect of duration on pitch perception

Roy,

I looked up your paper. Your experiments showed that complex tones
(evoking a residue pitch @ 100 Hz) are perceived about 4 times faster
than pure tones @ 100 Hz (melodic pitch task). The explanation given was
that you need a certain number of complete cycles (~4) to get a definite
pitch percept, and that in a complex tone the higher harmonics complete
many cycles per single cycle of the fundamental, thus providing a much
'faster' pitch percept. That's a little different than my argument, and
furthermore it seems to favor a temporal pitch coding mechanism, if
correct. Your experiments revealed no difference between complex tones
with resolved harmonics and poorly resolved harmonics, which also seems
to favor the temporal mechanism.

So there are at least two different explanations for why a complex tone
would evoke a pitch percept faster than a pure tone, neither of which
are based on traveling wave latencies...

Erik

Roy Patterson wrote: 
Ward, Martin and Erik,

With regard to:
Patterson, R.D., Peters, R.W., Milroy, R., 1983. Threshold duration for
melodic pitch. In: R. Klinke, W. Hartmann (Eds.), Hearing - Physiological
bases and Psychophysics, Springer-Verlag, Berlin, pp. 321-25.

My memory is that the explanation in the paper is essentially the same
as Erik's third hypothesis.

Regards Roy P

At 10:21 26/08/2005 -0400, you wrote:

Third: A (more?) probable reason for the stated difference in latency of
pitch perception between complex tones and pure tones is due to the fact
that a complex tone provides much more pitch information than a pure
tone (because of the additional harmonics). Whether pitch coding is
based on a place/pattern or temporal representation, it is a fairly
simple matter to go through the math (which we won't do here) and show
that the estimate of F0, from a noisy peripheral representation of
harmonic frequencies, increases in accuracy as the number of harmonics
increases. Because we can also assume internal noise (in the neural
processing), the time window that is required to estimate F0 to within
that internal noise limit, from the noisy peripheral representation,
will be lower for a complex tone than a pure tone.



* ** *** * ** *** * ** *** * ** *** * ** *** * ** *** * ** *** * ** ***
Roy D. Patterson
Centre for the Neural Basis of Hearing

NOTE: 10 April through 1 November, 2005,
The CNBH will be temporarily housed on the top floor of the
Craik-Marshall Building on the Downing Site. The Physiology Building is
being renovated.

My Room number is 317 and my phone number is 333936
My fax, email and web addresses are unchanged, and they are listed below


Physiology Department, University of Cambridge
Downing Street, Cambridge, CB2 3EG

phone   44 (1223) 333819        office
fax     44 (1223) 333840        department
email   rdp1@xxxxxxxxx
  or
email   roy.patterson@xxxxxxxxxxxxxxxxx

http://www.mrc-cbu.cam.ac.uk/~roy.patterson
http://www.mrc-cbu.cam.ac.uk/cnbh