The Role of Voice Fundamental Frequency in the Perception of Anger in Clear Speech

Purpose: While instructing talkers to speak clearly increases intelligibility, it often comes with an unintended consequence: listeners judge clear speech as sounding angry. The present signal-processing study examined whether the raised voice fundamental frequency ( f o ) commonly observed in clear speech causes this increase in perceived anger. Method: Sentences spoken by six talkers were edited to create four conditions: original conversational f o , conversational f o raised to match the f o of the identical sentence in clear speech, clear f o lowered to match the f o of the identical sentence in conversational speech, and original clear f o . Individual sentences were presented to 27 young adults with normal hearing, who indicated which emotion they heard out of six choices: “Anger,” “Fear,” “Disgust,” “Happiness,” “Sadness,” and “Neutral.” Results: While the expected difference in perceived anger between clear and conversational speech was found, shifting voice f o had very little effect on anger ratings. Perceived anger for the original and shifted f o conversational conditions did not differ significantly. Perceived anger was statistically significantly lower in the shifted f o clear condition versus the original clear condition, but the shifted clear speech was still rated as sounding angry over one third of the time. Conclusions: Raising the voice f o of conversational speech did not increase perceived anger ratings, while lowering the voice f o of clear speech only decreased these ratings a small amount. This suggests that other acoustic characteristics of clear speech are responsible for the unintended consequence of sounding angry.