Richard A. Roberts
Patrick W. Rappold
Michael P. Cannito
Dept. of Speech Pathol. and Audiol., Univ. of South Alabama, Mobile, AL 36688
Madhuri S. Muelkar
Univ. of South Alabama, Mobile, AL 36688
The results from an off-line procedure (scaling) were compared to those from an on-line procedure (``rate adjustment'') for effectiveness in examining the fusion strength of partials within two, three-tone complexes. In both procedures fusion strength was inferred by the ease in which a tone presented in isolation (captor tone), and alternately with a complex, was able to capture a member (target tone) of the complex into a sequential stream. In the rate adjustment procedure the interstimulus-interval (ISI) between captor and target was decreased until the listener judged the prominence of streaming to be greater than that of fusion. In the scaling procedure the ISI was held constant. On a visual analog scale, having its end points labeled ``fast'' and ``slow,'' subjects judged the prominence of the rate at which they heard the pitch of the captor tone. Stimulus factors were tone relationship (octave/inoctave) and tone position (low, middle, high). More of the total variation was explained by the rate adjustment procedure, but the coefficients of variation for each tone position were smaller for the scaling procedure. Neither procedure showed an effect of tone relationship (octave/inoctave), and both procedures showed the same effect of tone position.