Subject: Re: Perception as memory From: Pierre Divenyi <pdivenyi@xxxxxxxx> Date: Mon, 31 Aug 2009 08:49:09 -0700 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Dear Eric, Diana, Leon, and other AP fans, I have one problem with a basilar membrane interpretation of the AP shift: we are talking about chroma, not place and, because the thickness of the membrane is not uniform, it is har to believe that an age-related thickening would have the same effect (on a roughly logarithmic scale) over the whole length. This is why I am more in favor of assigning the (upward) shift to a central phenomenon, consistent with a slowing of the internal clock. Naturally, that would explain neither a downward shift nor a diurnal change. However, I am not sure how to interpret any diurnal change since, ever since Brady's experiment on learning AP "in 365 trials, one per day, in order to eliminate any relational judgment", and as a result of my own experience making me able to remember (and unable to rid myself of) a certain tonality over several hours, I have a great respect for relative pitch. So, if there is long-term memory for relative pitch, it will have to be considered a factor in any diurnal AP change. -Pierre On 8/31/09 8:12 AM, "Eric LePage" <ericlepage@xxxxxxxx> wrote: > In reply to your message dated 29/08/2009 at 16:18 > > Dear Diana, and list, > > Thanks for your personal comments. You noted: > >> Philip Vernon wrote an entertaining article about his shift of AP with >> age in the British Journal of Psychology 1977, 68, 485-489. > > I found the article in my reprint collection, but inside I found a letter > from Philip Vernon which accompanied the reprint, dated September > 19, 1978. He would then have been aged 72. Rereading the article > he specifically suggested how his experience is consistent with a > change in stiffness of the basilar membrane. > > One of his comments to me echoes your own comments about > variability: > > "My own hearing is, I would say, quite normal, apart from some > natural tendency to deafness with age. But the deviance of my > pitch norms is quite liable to fluctuate. E.g., at an ordinary orchestral > or chamber concert, I may start off identifying the keys a semitone too > high, and then notice half-an-hour later that everything is a tone too > high; sometimes, of course, I am uncertain of which is predominant. > But I don't seem to find any fluctuations with health, colds, or other > conditions. (Signed: Philip E Vernon)" > > ----- > So he seems to be suggesting that the same underlying parameter > varies in the short-term as well as with age. Perhaps the same > parameter explains the variation of AP with menses (Wynn, 1971) ? > Andrew Bell (HR1992) also showed that spontaneous OAE > frequencies also shift with menses, again suggesting a link > with cochlear mechanical stiffness. Recently I showed a post-hoc > analysis of CEOAEs suggesting a possible diurnal variation in the > whole-waveform reproducibility (p<0.01) (Acoustics Australia > April 2006). David Kemp did a prospective study (reported at > the 2008 mechanics meeting in Keele) and concluded there was > a diurnal variation in CEOAEs. Food for thought. > > Regards, > ELeP > www.oaericle.com.au >