[Effects of the speech rate on speakers' personality-trait impressions]

This study found non-linear functional relations between speech-rate and impressions of speakers' personality-traits. University students (N = 376) evaluated speakers' personality impressions for speech sounds that were converted at different speech-rates from the original utterance spoken by four Japanese and four native English speakers. A short version of the Big Five Scale based on the five-factor model of personality was used. Factor analysis showed that listeners recognized each personality-trait independently through speech sounds, and that speech-rate affected personality impressions of speakers differently depending on the traits. Multiple regression analysis revealed that quadratic regression equations could provide good approximations of personality-trait values, and all the non-linear relationships were described fairly well. The locations of the peaks and the spread of the quadratic functions vary from trait to trait. The complex metamorphosis of personality impressions via speech-rate converted sounds can be inferred by combining those five curves. Finally, participants showed more sensitive responses to Japanese speakers than to English speakers.