Jody Kreiman
Bruce R. Gerratt
Div. of Head and Neck Surgery, UCLA School of Medicine, 31-24 Rehab Ctr., Los Angeles, CA 90024-1794
Previous studies of pathologic vocal quality have not yielded a standard
set of scales for describing disordered voices, possibly due to the limited
number of voices studied. The present study used large sets (n=80) of male and
female voices, representing a broad range of diagnoses and vocal severities.
Eight experts judged the dissimilarity of each pair of voices, and responses
were analyzed using nonmetric individual differences multidimensional scaling.
Results indicate that differences between listeners in perceptual strategy are
so great that the fundamental assumption of a common perceptual space must be
questioned. Group spaces revealed a single ``feature'' (severity of pathology).
Spaces for individual listeners were characterized by clusters of voices which
seemed structured by ``family resemblances'': Each voice in a cluster resembled
others with rspect to some property, but the same property did not constitute
the resemblance for all voice pairs. Further, voices did not appear
consistently in the same clusters across listeners. In the absence of a common
perceptual space---of a shared sense of how voices sound similar---valid
perceptual scales cannot be defined. The results lead to the conclusion that
standardization of perceptual labels for voice quality is theoretically
impossible.