("(Yoshitaka Nakajima)" )

Subject: 
From:    "(Yoshitaka Nakajima)"  <nakajima(at)KYUSHU-ID.AC.JP>
Date:    Mon, 21 Sep 1992 15:41:58 JST

Dear Al and Dear colleagues,

I think to debug experiments in this network is far better than to be
debugged after submitting a paper.  Some people may abuse the system,
but to have several different systems for scientific discussion, e.g.,
journals, conferences and e-mail networks, is a good way to avoid
serious abuses of any system.  I agree to Dr. Hartmann's proposal that
we have to have a certain standard for claim staking.  We can discuss
the problem, maybe, after gathering some examples of claim staking.

Al's research plan seems interesting.  I think it is very important
to investigate the relationship between primitive organization and
speech perception.  Although I am almost a layman in the field of
speech perception, I am inclined to think combining spectral
components to perceive speech and to hear out a component are two
rather independent things which can be performed simultaneously
without serious conflict.  My opinion is based on an observation
performed by my students and me:

We made three spectral envelopes simulating Japanese vowels /a/,
/i/ and /u/.  Inharmonic spectral components at intervals of
500 cents glided in the same direction (upward or downward) for
500 cents taking 400 ms.  We gave a rise- and a fall-time of 10
ms to each stimulus tone.  The question, related to the present
topic, was, whether we could perceive the vowels or not.  I must
say it was sometimes difficult to perceive any vowels.  But finally,
we learned how to perceive vowels within these peculiar stimuli.
Some people could perceive the vowels immediately.  When two
different stimuli, e.g., /a/ and /i/, were presented successively,
the vowels were rather clear.  An interesting thing was that, all
of us had an impression that these vowels were spoken by several
speakers.  In my case, about six male speakers seemed to utter the
vowels.  Now, the perception of vowels can take place only when
we can integrate several spectral components perceptually.  On the
other hand, perceiving several voices means we are separating
inharmonic components somehow.  This observation suggests that
speech perception takes place even when spectral components are
segregated in a primitive aspect.  There is, however, another
possible explanation: The listeners may have picked out just the
formants to perceive vowels, and the rest of the components may
have contributed to increase the number of voices.  But, then,
it would be difficult that the voices are heard as male voices.
Reducing the number of components would give us a clearer view,
and I am planning to do some more observations with one of my
students.

					Yoshitaka Nakajima