Effects of fundamental frequency and vocal tract length changes on attention to one of two simultaneous talkers.

The study conducts three experiments to check the effects of fundamental frquency and vocal-tract length changes on attention to one of two simultaneous talkers. The three experiments used the Coordinated Response Measure task to examine the roles that differences in F0 and differences in vocal-tract length have on the ability to attend to one of two simultaneous speech signals. Exp 1 asked how increases in the natural F0 difference between two sentences affected listeners' ability to attend to one of the sentences. Exp 2 used differences in vocal-tract length, and the third used both F0 and vocal-tract length differences. Exp 3 was varied both F0 and vocal tract length in concert to simulate a smooth transition between a same-sex and different-sex masking voice. Overall, it was found that shifting one of two female utterances towards a male voice resulted in improvement in performance whereas shifting male towards female did not. Performance increase varied with intonation patterns, being smallest for those speakers who showed most variability in intonation between utterances