Dr. Pennebaker, chair of the psychology department at the University of Texas at Austin and author of The Secret Life of Pronouns: What Our Words Say About Us, is on a roll lately.
His research was picked up by WSJ:
"112 psychology students were assigned to same-sex groups of two. The pairs worked to solve a series of complex problems. All interaction took place online. No one was assigned to a leadership role, but participants were asked at the end of the experiment who they thought had power and status. Researchers found that the higher the person's perceived power, the less he or she used 'I.' "