This is one of the questions Ohio State University psychologist Richard Petty considered when he began studying the effect of behavior on a person’s emotional state.

“We know the direction of the effect usually goes from how a person feels to that person’s body conforming. You’re frightened and then you run away,” he explained. “We were interested in looking at whether or not this could be reversed.”

To find out, Petty and fellow researchers Pablo Briñol and Benjamin Wagner studied body posture and how it affects a person’s confidence in his thoughts. The results showed that those who sat up straight exhibited greater confidence than those who slumped, bolstering the theory that behavior can influence how a person feels. The study appeared in the current issue of the European Journal of Social Psychology.

In the experiment, roughly half of the 71 participants were asked to sit with their back erect and chest out. The other half were told to sit while slouched forward. Some members from each posture group were then asked to write positive qualities about themselves under the guise of a job application study. The others were asked to write negative qualities about themselves. Afterwards, all of them were asked to rate their potential as job candidates.

Participants who sat upright during the writing exercise were more likely to rate their job prospects in line with the positive and negative traits they listed. Conversely, those who sat while slouched forward did not seem to believe their own thoughts.

“The people who were sitting up straight really took to heart what they wrote. They had a much more favorable impression of themselves,” Petty said, adding, “It’s surprising that something as simple as this momentary posture can have such an effect on people’s self-judgments.”

Stanford University professor and behavior specialist Zakary Tormala agreed.

“The finding that people can be induced to trust or doubt their own thoughts merely by changing their sitting position is both theoretically interesting and very important from a practical perspective,” he said. “This research breaks new ground by highlighting an important mind-body connection in the formation and change of people’s attitudes.”

Derek Rucker, a marketing professor at Northwestern University’s Kellogg School of Management, praised the study as well, calling it an “important contribution” to the literature on embodied cognition, the theory that how people feel is affected by their behavior.

“The work speaks to the importance of embodied cognition and how our physical positions can affect our thought processes,” he said.