Preprint_Vertical motion facilitates pitched vocalization

When asked to speak in response to a visual motion stimulus, participants tend to respond to upward/downward visual motion with a higher/lower auditory pitch, respectively, indicating that visual and speech production processing are linked (Shintel et al., 2006). However, in previous studies, participants have been asked to say words with specific meanings (“up” and “down”) and acoustic characteristics (high/low pitch) that could influence the findings. To address this issue, we tested pitch-motion correspondence between visual motion and pitched speech production of a high- or low-pitched meaningless single vowel [a] in response to the upward or downward direction of a visual motion stimulus. The results show that pitched speech production was executed more quickly when the expected pitch corresponded (consistent condition) versus did not correspond (inconsistent condition) with the visual motion direction. This result indicates that the pitch-motion correspondence in speech production does not depend on meaning or acoustic factors. To evaluate the effects of pitch-motion correspondence on speech production, we examined several acoustic parameters of the produced speech. Our acoustic analysis indicated that the produced speech in the consistent condition reflected lower stress, higher confidence, and greater fluency compared with that in the inconsistent condition. These findings highlight the advantages of using speech production to show acoustic parameter modulation, which cannot be addressed using conventional behavioral measures such as a keypress.