Subject: Re: Perception as memory From: Diana Deutsch <ddeutsch@xxxxxxxx> Date: Mon, 31 Aug 2009 14:32:46 -0700 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Dear Eric and list, Thanks for your very informative postings. So from your experience, as well as Vernon's, Leon's, Pierre's, and others, it appears that for the majority of people with AP (though not all) the pitch 'grid' shifts upwards with age. This leads me to wonder whether this might be a more general phenomenon, and not just confined to people with AP. How can one document experimentally, for people who don't have a labelled internal reference, that they begin to hear 'sharp', assuming that they preserve the relationships (musical intervals) between the perceived pitches? My sense is that this would be very difficult to do, as a purely perceptual experiment. But physiological measures, such as brain stem following, might provide some answers. Regards, Diana On Aug 31, 2009, at 8:12 AM, Eric LePage 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 >