Subject: Re: Motor theory of absolute pitch From: Harry Erwin <harry.erwin(at)SUNDERLAND.AC.UK> Date: Thu, 10 May 2001 09:38:40 +0100>Rebecca and others have suggested that absolute pitch may rely to >some degree on muscle memory. I have two comments. > >First, I believe that absolute pitch is of interest because it >putatively involves some sort of unusual/special memory ability. It >appears that possessors have stable long-term representations of >musical pitch, and they are able to categorize or label these >representations with linguistic labels. If AP is subserved by >muscle-memory, that doesn't make it any less interesting it seems to >me -- we are simply specifying the type of memory that is involved, >but it is still a feat of memory. > >Second, and more relevant, the late Dixon Ward and Ed Burns conducted >a study that addresses this issue head on. Ward and Burns (1978) >denied auditory feedback to trained singers who possessed absolute >pitch (forcing them to rely solely on muscle memory); the singers >erred by as much as a minor third, or three semitones. Thus muscle >memory was only enough to get them in the ball park, and did not >account for their AP ability. > > >Ward, W. D. & Burns, E. M. (1978) . Singing without auditory >feedback. Journal of Research in Singing and Applied Vocal Pedagogy, >1(2), 24-44 > >Dan Levitin > That sounds like feedback control via the auditory system. You might look at how continuous-wave (CW) bats do it. Note also that CW bats use doppler shift to detect insect wingbeats and possibly to declutter the scene. Schuller, et al., 1974, in "Response to frequency shifted artificial echoes in the bat _Rhinolophus_ _ferrumequinum_," J. Comp. Physiol., 89:275-286, reports that R. ferrumequinum maintains its CF with an observed accuracy of +/- 50 Hz. This bat's resting frequency is about 82.5 KHz, so that corresponds to about 0.06 percent variation. For a human singer at 440 Hz, a similar accuracy would be +/- 0.2-0.3 Hz. Hyperacuity probably plays a role. --- Harry Erwin, PhD, Senior Lecturer of Computing, University of Sunderland. Computational neuroscientist modeling bat bioacoustics and behavior. <http://world.std.com/~herwin>