Effects of task-irrelevant and stimulus type on the correspondence between spatial position and vocal pitch

Abstract

The present study investigated the crossmodal correspondence between the spatial position of visual stimuli and vocal pitch, building on the findings of Suzuki and Nagai (2020). We aimed to clarify the conditions under which this correspondence emerges, focusing on task-irrelevant spatial information (Experiment 1) and symbolic spatial cues such as arrows (Experiment 2). In Experiment 1, participants produced high- or low-pitched vocal responses based on the color of visual stimuli presented above or below a central fixation point. In Experiment 2, participants responded to the orientation of arrows pointing upward or downward. Results showed that in both experiments, vocal responses congruent with the spatial information of the visual stimuli (high/low) were executed more quickly than incongruent responses. These findings indicate that the spatial position–vocal pitch correspondence occurs regardless of the task relevance or presentation format of the spatial information. Moreover, acoustic analyses in Experiment 1 revealed that congruent-pitched vocal responses exhibited increased Cepstral Peak Prominence Smoothed (CPPS), reflecting enhanced vocal fluency. In contrast, Experiment 2 showed no significant effects on CPPS, suggesting that symbolic stimuli requiring internal spatial encoding may not facilitate the motoric aspects of vocal production to the same extent as physically displaced stimuli. These results suggest that the salience and physical characteristics of visual stimuli may determine whether crossmodal correspondence influences the motor execution of vocal responses (i.e., fluency). Overall, this study extends previous work by demonstrating that spatial–pitch correspondence generalizes across different stimulus formats and can facilitate a vocal response.