The subtle changes may help assess linguistic development in children who otherwise are too young too communicate to researchers. Credit: monkey business images via Getty Images

Your eyes really can betray your thoughts, but don’t get too self-conscious about it. Researchers in Japan believe that the subtle signs our eyeballs make are more useful to neuroscientists than the interrogation room. Based on their findings recently published in the journal iScience , examining the difference physiological responses from “ inner ” versus “overt” speech may help us better understand everything from linguistic development in children to the efficacy of silent pep talks.

To learn more, a team at the University of Tsukuba in Honshu enlisted dozens of volunteers for a series of simple counting exercises.…