A closer look at “Pupil Size Reveals Key Differences Between Speaking Aloud and Inner Speech”, exactly as the source publishes it. A new study published in the journal Psychological Science finds that pupil size can distinguish between speaking aloud and inner speech, offering a physiological marker for the internal monologue. Researchers from the University of Wisconsin–Madison and the University of California, Berkeley, led by Dr. Daniel Casasanto, measured pupil dilation in participants who either vocalized words or silently imagined saying them.
The results showed that both conditions triggered pupil dilation, but inner speech produced a more delayed and attenuated response compared to overt speech. This suggests that inner speech, while sharing neural mechanisms with spoken language, is not simply 'silent talking' but a distinct cognitive process. The findings could have implications for understanding conditions like schizophrenia, where inner speech is disrupted, and for developing brain-computer interfaces that rely on imagined speech. The full version stays on the original page, which this listing opens directly.