Private speech improves cognitive performance in young adults.

The current study investigated the relationship between private speech usage and cognitive performance in young adults. Participants (n = 103, mean age = 20.21 years) were instructed to complete a visual-spatial working memory task while talking out loud to themselves as much as possible (Private Speech condition). We found that participants performed better on trials for which they produced a greater amount of private speech. To establish causality, we further found that participants performed better in the Private Speech condition than in a condition in which they were instructed to remain silent (Quiet condition). These beneficial effects of private speech were not moderated by task difficulty, which was manipulated by varying image labelability. However, participants who used more private speech during the task, as well as those who reported greater use of self-management private speech in everyday life, showed the greatest benefits. These findings have implications for real-world educational/instructional settings.