As practicing statisticians who work in social science, we have a dark secret to reveal: Some of the most glamorous, popular claims in the field are nothing but tabloid fodder. The weakest work with the boldest claims often attracts the most publicity, helped by promotion from newspapers, television, websites, and best-selling books. And members of the educated public typically only get one side of the story.
Consider the case of Amy Cuddy. The Harvard Business School social psychologist is famous for a TED talk, which is among the most popular of all time, and now a book promoting the idea that “a person can, by assuming two simple one-minute poses, embody power and instantly become more powerful.” The so-called “power pose” is characterized by “open, expansive postures”—Slate’s Katy Waldman described it as akin to “a cobra rearing and spreading its hood to the sun, or Wonder Woman with her legs apart and her hands on her hips.” In a published paper from 2010, Cuddy and her collaborators Dana Carney and Andy Yap report that such posing can change your life and your hormone levels. They report that the “results of this study confirmed our prediction that posing in high-power nonverbal displays (as opposed to low-power nonverbal displays) would cause neuroendocrine and behavioral changes for both male and female participants: High-power posers experienced elevations in testosterone, decreases in cortisol, and increased feelings of power and tolerance for risk; low-power posers exhibited the opposite pattern.”
Cuddy’s work on power posing has been covered in the press for years, including in Waldman’s tongue-in-cheek article in Slate. Most of the time, that coverage is glowing. Here’s a recent New York Times review of Cuddy’s new book, Presence: Bringing Your Boldest Self to Your Biggest Challenges: “While Cuddy’s research seems to back up her claims about the effects of power posing, even more convincing are the personal stories sent to the author by some of the 28 million people who have viewed her TED talk. … Unlike so many similar books aimed at ushering us to our best lives, Presence feels at once concrete and inspiring, simple but ambitious—above all, truly powerful.” And here’s a CBS News report from last month: “Believe it or not, her studies show that if you stand like a superhero privately before going into a stressful situation, there will actually be hormonal changes in your body chemistry that cause you to be more confident and in-command. … [M]ake no mistake, Cuddy’s work is grounded in science.”
But the story of power posing is not so simple. An outside team led by Eva Ranehill attempted to replicate the original Carney, Cuddy, and Yap study using a sample population five times larger than the original group. In a paper published in 2015,the Ranehill team reported that they found no effect.
This is not such a surprise. Cuddy’s scientific claim was, as is typically the case, based on finding “statistically significant” results in experiments. We know, though, that it is easy for researchers to find statistically significant comparisons even in a single, small, noisy study. Through the mechanism called p-hacking or the garden of forking paths, any specific reported claim typically represents only one of many analyses that could have been performed on a dataset. A replication is cleaner: When an outside team is focusing on a particular comparison known ahead of time, there is less wiggle room, and results can be more clearly interpreted at face value. The original power-pose study reported an impressively large effect, but that’s what happens with published results from small, noisy studies: Variation is high, so anything that does appear to be statistically significant (the usual requirement for publication) will necessarily be large, even if it represents nothing but chance fluctuation.
In a post from May 2015, psychology researchers Joe Simmons and Uri Simonsohnanalyzed the original power-pose study and its unsuccessful replication in detail, writing:
The power-posing participants were reported to have felt more powerful, sought more risk, had higher testosterone levels, and lower cortisol levels. In the replication, power posing affected self-reported power (the manipulation check), but did not impact behavior or hormonal levels. The key point of the TED Talk, that power poses “can significantly change the outcomes of your life,” was not supported.
Here’s their summary:
Simmons and Simonsohn write, “even if the effect existed, the replication suggests the original experiment could not have meaningfully studied it.” The replication showed similar negative results on hormones, and after an analysis of results from a collection of other published studies, they conclude, “at this point the evidence for the basic effect seems too fragile to search for moderators or to advocate for people to engage in power posing to better their lives.” In other words, the data are completely consistent with power poses having no effect. Or with a small undetectable positive effect. Or, for that matter, with a small negative effect.
Simmons and Simonsohn shared their analysis with Cuddy, who replied, “I’m pleased that people are interested in discussing the research on the effects of adopting expansive postures. I hope, as always, that this discussion will help to deepen our understanding of this and related phenomena, and clarify directions for future research. … I respectfully disagree with the interpretations and conclusions of Simonsohn et al., but I’m considering these issues very carefully and look forward to further progress on this important topic.”
Cuddy also pointed to a response that she had published, along with Carney and Yap, in the journal Psychological Science. Nowhere in that response, though, did Cuddy and her collaborators consider that their original paper may have been in error.
We understand this response—Cuddy has had a lot of success with this research so it would take a lot for her to give up on it—but we would prefer if she would consider the possibility that her original finding was spurious.
This is not to say that the power pose effect can’t be real. It could be real and it could go in either direction. We could imagine, for example, that sitting in a power pose gives people an overconfidence that could harm them in negotiations. Or that the power pose could help some people and hurt others. The point is, speculation is cheap. What got Cuddy and her theories such attention and respect, in addition to her excellent public-speaking skills, is the claim that it is “grounded in science”—the statistically significant result that was published in a top journal. But this evidence is thrown in doubt by the nonreplication of Ranehill et al., the careful analysis of other work by Simmons and Simonsohn, and the general statistical principles that explain how it is possible for researchers to find apparently strong evidence out of noise.
The unsuccessful replication got some scattered press coverage—the Huffington Post ran a story, for instance—but far less than the original claim received, and continues to receive, in the mass media.
If you read the New York Times, watch CBS News, or tune in to TED talks, you will encounter the power pose as solid science with a human touch. These media organizations portray it as a laboratory-tested idea that can help people live their lives better. But TV–approved and newspaper-endorsed social science is for outsiders. Insiders who are aware of the replication crisis in psychology research are suspicious of these sorts of dramatic claims based on small experiments. And you should be too.
The unsuccessful replication by Ranehill et al. appeared in mid-2015, as did the post by Simmons and Simonsohn. But half a year later, the Times and CBS continue to report Cuddy’s claims as fact. The CBS report includes only the most minimal sort of disclaimer:
There has been some criticism of Cuddy’s theories from other researchers, some saying that it only works in very specific kinds of circumstances.
“I welcome challenges that help us grow the science and move it forward,” said Cuddy. “The better we understand it, the better we can use it.”
This is completely misleading. The critics find no evidence that power posing “works” at all in the sense argued by Cuddy. As Simmons and Simonsohn write, “The key point of the TED Talk, that power poses ‘can significantly change the outcomes of your life,’ was not supported.”
Our point here is not to slam Cuddy and her collaborators Carney and Yap. We disagree with their interpretation of the statistics and are disappointed that they don’t seem to consider the possibility that their published result was spurious. But it is natural for researchers to feel strongly about their own research hypotheses. Outside research teams have attempted replications, these null results were themselves published, and science is proceeding as it should.
In writing this column, we hope to give you the perspective that you might not get from the New York Times, CBS News, or other news outlets that present gee-whiz science publications at face value. Rather, we want to highlight the yawning gap between the news media, science celebrities, and publicists on one side, and the general scientific community on the other. To one group, power posing is a scientifically established fact and an inspiring story to boot. To the other, it’s just one more amusing example of scientific overreach. So let’s put power posing where it belongs, alongside the claim that college men with fat arms are more likely to have certain political attitudes and that ovulating women are more likely to wear red.And we are not really criticizing the New York Times or CBS News, either. We all have been conditioned to believe that scientific publications represent truth, and it is taking the journalistic profession awhile to unlearn this lesson.