Perceptual adaptation to gender and expressive properties in speech: the role of fundamental frequency.

Recent studies have demonstrated perceptual adaptation to nonlinguistic properties of speech involving voice gender and emotional expression. The present study extends this work by examining the contribution of fundamental frequency (F0) to these effects. Voice recordings of vowel-consonant-vowel (VCV) syllables from six talkers were processed using the STRAIGHT vocoder and an auditory morphing technique to synthesize gender (experiment 1) and expressive (experiment 2) speech sound continua ranging from one category endpoint to the other (female to male; angry to happy). Continuum endpoints served as adaptors for F0 present and F0 removed conditions. F0 removed stimuli were created by replacing the periodic excitation source with broadband noise. Confirming previous findings, aftereffects were found in the F0 present condition, resulting in a decreased likelihood to identify test stimuli as belonging to the adaptor category. No aftereffects appeared when F0 was removed, highlighting the importance of F0 in adaptation. However, in an identification test listeners were still able to categorize F0 removed stimuli at better-than-chance levels, indicating that residual cues for gender and emotion were available even when F0 was not present.