Psychologists often remark that our internal emotional state is mirrored by our body’s posture and facial expressions. When we feel sad or afraid, we often use a slumped posture, whereas when people feel happy and confident, they use an upright posture. Some research suggests that this dynamic can work in reverse too, meaning your posture can affect your mood, which leads us to the so-called “superhero” pose.

First introduced by social psychologist Amy Cuddy, this power posing is supposed to encourage the production of high testosterone levels and low cortisol (stress hormone) levels in the bloodstream, thereby elevating self-esteem and boosting confidence. Those are pretty bold claims, but does it actually work?

Researchers at Martin Luther University Halle-Wittenberg (MLU), the University of Bamberg, and The Ohio State University recently published a meta-analysis, which looked at data from close to 130 experiments that explored power posing, totaling 10,000 participants. The objective was to find out whether consciously deciding to have a certain posture can influence a person’s confidence, behavior, and hormone levels.

Although many studies were small or inconclusive, the researchers could make the assertion that an upright posture and power posing were linked to a more positive self-perception. There was no difference between men and women for these effects.

The power pose, also known as the Superman or Wonder Woman poses, involves standing tall with your chest out and your hands on your hips. The upright pose is slightly different from the power pose, in the sense that you still stand tall but you’re not as intimidating. High power poses can present a threat to interaction partners and may be regarded as a display of dominance, upright postures typically create an impression of competence and can be interpreted as a display of prestige.

 “In therapy, they (body language and posture) can help people feel secure and experience positive feelings,” says psychologist Robert Körner from MLU and the University of Bamberg.

“A dominant pose can, for example, make you feel more self-confident,” added personality researcher Professor Astrid Schütz from the University of Bamberg.

A less robust, but still slightly significant connection was found between power posing and positive behaviors, such as task persistence and decreased antisocial behavior.

However, the researchers did not find enough reliable evidence to back up the assertion that certain poses influence the production of testosterone and cortisol. Although some studies claim otherwise, the researchers concluded that those findings were either not robust or couldn’t be replicated by other groups of researchers. The confidence boost of certain postures may be purely psychological, rather than owed to some biological mechanism.

As a caveat, the authors of the study mention that almost all of these studies have been conducted in mainly Western, developed societies. The same may not apply at all in other cultures, such as among some people living in Africa and Asia.

Bottom line is that power posing does really seem to work, though If you’re new to this you might want to dial it down a bit. Looking confident is one thing, but you don’t want to appear too domineering or intimidating.

The findings appeared in the journal Psychological Bulletin.