Hearing smiles and frowns in normal and whisper registers.

Two experiments measured listeners' abilities to detect facial expression in unfamiliar speech in normal and whisper registers. Acoustic differences between speech produced with neutral or marked facial expression were also assessed. Experiment 1 showed that in a forced-choice identification task, listeners could accurately select frowned speech as such, and neutral speech as happier sounding than frowned speech in the same speakers. Listeners were able to judge frowning in the same speakers' whispered speech. Relative to neutral speech, frowning lowers formant frequencies and increases syllable duration. In both registers, judgments of frowning and its relative happiness were significantly poorer for lip-rounded vowels, suggesting that listeners may recover lip protrusion in making judgments. Experiment 2 replicated the finding [V. Tartter, Percept. Psychophys. 27, 24-27 (1980)] that listeners can select speech produced with a smile as happier sounding than neutral speech in normal register, and extended the findings to whisper register. Relative to neutral, smiling increased second formant frequency. Results are discussed with respect to nonverbal auditory emotion prototypes and with respect to the direct realist theory of speech perception.