Nodding Brings Confidence

Head movement influences conviction of thoughts.

By Colin Allen, published on July 01, 2003

Certitude is just a nod away. Nodding or shaking your head appears to influence your thoughts, researchers have found. While nodding, subjects are more confident in their opinions. Head-shaking has the opposite effect, leaving people less convinced about their own judgements.

Richard Petty, Ph.D., a professor of psychology at Ohio State University and co-author of the study, recruited 82 subjects to conduct this study. In order to hide the real purpose of the experiment, he told them they would be assessing headphone sound quality. Half of the group nodded while the other half shook their heads, ostensibly to mimic listening while jogging.

Heads waggling, the subjects listened to one of two radio shows. Both featured an editorial advocating university ID cards. In one recording, the host gave a strong, logical argument in favor of student IDs. In the other, the DJ gave a half-hearted and unpersuasive argument for them. Afterward, participants were asked how they felt about both the editorial and the headphone quality.

Nodders who listened to the strong argument supported IDs more enthusiastically than shakers. Conversely, nodders listening to the weak argument tended to feel more strongly that the ID idea was bad. "When people were nodding up and down they became more confident in what they were thinking," explains Petty.

Petty found similar body-mind connections in handwriting. In this case, writers were asked to write 3 positive or negative qualities about their future careers. When writing with their less dominant hand, subjects registered less confidence about their career choice.

The study was published June in the Journal of Personality and Social Psychology.