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Re: MDS distances

I think the Gray/Wessel approach has failed.. it's too hard to figure
out what the results mean.  (Just trying to be blunt to get your
attention. ;-)  You start with convenient sounds, measure perception
and then try to figure out what the MDS dimensions mean.  That hasn't
worked.  I think that is why people have not been pushing on it very
hard lately.

One should not try to interpret the "meaning" of MDS dimensions, since any rotation of an MDS solution is a completely equivalent solution. Hence, looking at the vectors components of an MDS solution has no sense unless you find a way to fix some dimensions in a meaningful way. That's why different MDS algorithms can lead to different (valid) solutions given the same initial similarity matrix. If your goal is to find the "intrinsic" dimensions of sound data, my opinion is that it would be preferable to use state-of-the-art dimensionality reduction algorithms (Isomap, LLE, non-local techniques, or even PCA), on a set of points obtained from MDS with no loss in higher dimension.

Jean-François Paiement
Research Assistant
IDIAP Research Institute
Martigny, Switzerland