ASSESSING THE COGNITIVE LOAD OF TALKING IN WHISPERS AND CLEAR SPEECH WITH A MODIFIED SIMON TASK

This study aimed to examine the cognitive demand associated with different speech production modes. Fifteen vocally healthy college students performed a Simon task, a method widely used to evaluate cognitive load via response times to visual stimuli. Participants performed the task both in silence and while counting numbers in three speech modes: habitual speech, whisper, and clear speech. The reaction time was measured for 'congruent' and 'incongruent' trials, which referred to whether the locations of the square and the key assigned to the square's color matched or mismatched, respectively. Results revealed that all modes of speech production significantly increased cognitive load compared to silence. Among the speech production modes, clear speech elicited longer reaction times than whispering or habitual speech. However, this effect was only observed in congruent trials, suggesting that the cognitive load, associated with managing spatial incongruity, might mask subtle differences in cognitive load between speech production modes. Collectively, our findings suggest that clear speech is more cognitively demanding than habitual speech or whispering, and that reaction times in the Simon task may serve as an effective proxy for cognitive load during speech production.