When a 2010 study touted that making a power pose—like a Wonder Woman stance with hands on hips and shoulders back—for just two minutes before an important encounter could boost confidence by increasing certain hormones, it made quite the splash. 

 

In the ensuing years, however, numerous researchers have tried to replicate those findings, to no avail. The most recent attempt comes from Penn scientists Coren Apicella and Kristopher Smith, who published their results in Hormones and Behavior.

 

“We failed to find any of the original effects,” says Smith, a fourth-year Ph.D. student in the Department of Psychology in the School of Arts & Sciences. “One might not be able to ‘fake it until they make it’ and in fact, doing so might be detrimental.”

 

Smith and Apicella, an assistant psychology professor, aimed to repeat the original experiment, but in a broader context backed by evolutionary theory. They used the same poses and facial-expression images, but increased participant numbers from 42 to more than 240 and opted for males only to eliminate large differences in initial hormone levels. 

 

Perhaps most importantly, they incorporated tug-of-war competitions that resulted in one declared victor and loser for each round. 

 

“We know that hormones change in this context, especially testosterone,” Apicella says. “Winners get a little increase in testosterone, losers get a relative decrease. The evolutionary theory for that is if you just won a competitive interaction, that testosterone is enabling you to take on future competition. If you lost, it’s saying, 'You don’t want to get your butt kicked again.'”

 

After the contest, based on random assignments, participants made a high power pose, where the body takes up as much space as possible, a low power pose, where the body shrinks or constricts, or a neutral pose. While posing, study subjects viewed faces on a computer screen. 

 

The researchers then measured hormone levels via participants’ saliva, compared against baseline samples taken at the experiment’s start. 

 

Not only did the original results not hold up, but Apicella and Smith actually discovered these gestures could potentially cause harm. 

 

“The losers [of the tug-of-war] in our study who took winner poses experienced the biggest decline in testosterone,” Apicella says. “From an evolutionary perspective, that could make sense.”

 

She brings up one 1977 experiment in which a researcher painted the plumage of low-ranking sparrows to mimic that of more dominant birds to test why the weaker sparrows did not fake a higher ranking. The true high-ranking birds mistreated the “fakers.” 

 

“Our study is more in line with these results,” Apicella says. “This was one of several tests that didn’t go in the direction we predicted.” However, she stresses the need to replicate these findings before drawing any further conclusions. 

 

And to those who ask why such low-cost behaviors like power poses matter, Smith says there’s more to it. 

 

“If psychology is to be a trusted source of information when the stakes are high, then we have to make sure we’re getting it right even when the stakes are low,” he says.