Re: Absolute pitch discussion

[Martin Braun <nombraun@xxxxxxxxx>]

Bill Yund wrote:

"A skill will show such a bimodal distribution if it
is something that is not learned in normal everyday activities.  Those
who take up activities that teach the skill will be on one end of the
distribution and us others will be on the other end."

This is simply not true. Any skill teaching in a group of subjects results 
in a one-mode distribution of the teaching results. All environmental 
factors and all teaching activities, however, that have been associated with 
the development of absolute pitch clearly result in a two-mode distribution: 
a zero-AP cluster that is sharply separated from an excellent AP cluster. No 
environmental factor can explain this dichotomy.

In certain tasks of problem solving it can happen that two discrete 
strategies are possible. In such a case test results can be bimodal. Pitch 
naming is not such a case.

Martin

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Martin Braun
Neuroscience of Music
S-671 95 Klässbol
Sweden
web site: http://w1.570.telia.com/~u57011259/index.htm





----- Original Message ----- 
From: "yund" <yund@xxxxxxxxx>
To: <AUDITORY@xxxxxxxxxxxxxxx>
Sent: Saturday, September 01, 2007 12:43 AM
Subject: Re: Absolute pitch discussion


Contrary to Braun's claim, a bimodal distribution like that of Fig. 1
in the PNAS paper, is not strong (or even weak) evidence for a simple
genetic factor.  A skill will show such a bimodal distribution if it
is something that is not learned in normal everyday activities.  Those
who take up activities that teach the skill will be on one end of the
distribution and us others will be on the other end.  Of course, there
will also be some individuals in the intermediate range (as in the cited
Fig. 1) due to statistical properties of testing, incomplete learning,
generalization from other abilities, or something else.

Another possible explanation (also more likely than a simple genetic
factor) is an early environmental factor that biases development of the
trait.

I am not an expert in genetics, but I have often heard my wife (who does
have these credentials) vent her frustrations at claims of a simple
genetic factor on the basis of such non-evidence.

Bill Yund
------------------------------------------
E. William Yund, Ph.D.

Hearing Loss Research Laboratory (151/MTZ)
VA Northern California Health Care System
150 Muir Road
Martinez, CA 94553

yund@xxxxxxxxx
(925)372-2296
FAX (925)228-5738
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