Subject: Re: Effect of duration on pitch perception From: Erik Larsen <elarsen(at)MIT.EDU> Date: Fri, 26 Aug 2005 11:31:46 -0400Roy, I looked up your paper. Your experiments showed that complex tones (evoking a residue pitch (at) 100 Hz) are perceived about 4 times faster than pure tones (at) 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(at)cam.ac.uk > or > email roy.patterson(at)mrc-cbu.cam.ac.uk > > http://www.mrc-cbu.cam.ac.uk/~roy.patterson > http://www.mrc-cbu.cam.ac.uk/cnbh >