Guest post: Pulling the Plug on Power Posing

JAC: We met Dorsa Amir a while back when she sent us photographs of the Barbary macaques she worked on in Morocco’s Atlas Mountains (she also sent a photo of her orange tomcat Emerson). She recently called my attention to Amy Cuddy’s popular TED video on “power posing”, as Cuddy’s conclusion about hormones and behavior is relevant to Dorsa’s thesis work. Not only that, but Cuddy’s talk, now up to 25,758,838 views, is the second most popular TED talk of all time. But, referring me to an analysis on another site, Dorsa told me that Cuddy’s conclusions were dubious—or at least non-repeatable. I asked her to write a post about it, which is below. I’ve also put in Cuddy’s talk, which I recommend you watch, so you can see her claims and how much the audience loved it.

First, Dorsa’s information:

I’m a PhD student in biological anthropology at Yale University. My research interests include the physiology and psychology of contemporary humans, with a focus on small-scale societies. I spend my summers in South America with the Shuar of eastern Ecuador, as part of the Shuar Health and Life History Project
Personal site:


Pulling the Plug on Power Posing

by Dorsa Amir

If you’ve seen just one TED talk, I would bet it’s called “Your body language shapes who you are” by Amy Cuddy, now an Associate Professor at Harvard Business School. This is a pretty safe bet, for in the three years since its release, Cuddy’s talk has racked up more than 25 million views, making it one of the most popular TED talks of all time.

In the talk, Cuddy presents data from her 2010 article in Psych Science which makes the following claim: by simply changing your posture to a “high-power” pose (i.e., taking up more space and opening your limbs), you can instantly trick your body into thinking it’s more powerful. The authors tested this claim by having 42 participants give saliva samples, engage in either a high-power or a low-power pose for two minutes (depicted below), then give another saliva sample.


The saliva tubes were then sent off to a lab and analyzed for two specific hormones: testosterone and cortisol. Interestingly, the power posing appeared to have a significant effect on hormone levels: high-power poses were associated with a rise in testosterone and a drop in cortisol, and low-power poses with the opposite. So not only did the posing make you feel more powerful, it also made your body more powerful by fiddling with your hormone levels and making you literally embody that power.

DataColada vs. Power Posing:

So why are we talking about a video from three years ago? Well, in a blog post on Friday, the talented folks over at DataColada tackled the evidence supporting power posing. As it turns out, as shown in a recent paper in Psych Science, the power posing effect doesn’t seem to replicate. I suggest checking out the full blog post for details, but here are their main points:

  • The replication method in the new study is precise enough to be informative.
  • The original sample size of N=21 per cell had less than 6% statistical power to detect the effect, even if it existed. This is problematic: even if you do find the effect, being so extremely underpowered decreases the likelihood that the effect is real. In other words, the smaller your sample size, the greater the likelihood of a false positive.

As the bloggers claim, “if studies only get published when they show an effect, the fact that all the published evidence shows an effect is not diagnostic”. So what you can do, and what they did, is run a fancy statistical method called a p-curve analysis; a method that lets you rule out selective reporting as the only explanation for a set of significant findings.

Check out the two example graphs below, comparing a good to a bad p-curve. On the X-axis is the p-value reported in any one study, and on the Y-axis is the percentage of studies that have that p-value. This lets you compare p-values for the same experimental protocol across many studies and see what the curve looks like. You want a right-skewed curve because that indicates that proportionally more studies are reporting effects that are significant at lower values. So, if power posing is real and effective and robust, as assessed in 33 separate studies, you should see a right-skewed p-curve. You don’t want to see a flat curve, because that means that all the different p-values are equally likely to occur.

Screen Shot 2015-05-10 at 6.26.59 AM

Here’s what the actual p-curve analysis looks like:

Screen Shot 2015-05-10 at 6.26.47 AM

We see not the right-skewing that would convince us that this is a real effect, but rather a flattish curve that should make us question the finding.

The DataColada folks conclude, “At this point the evidence for the basic effect seems too fragile…to advocate for people to engage in power posing to better their lives.”

Hormones & Behavior:

I’d like to take a minute here to add my two cents. In our lab at Yale, my colleagues and I spend a lot of time thinking about hormones—our lab meetings are affectionately referred to as “Hormone Happy Hour”—and we spend a lot of these meetings discussing the relationship between hormones and behavior. As it turns out, hormones, like everything else in biology, are kind of complicated. While testosterone and cortisol have been implicated in basically every human behavior, let me share the basics. Testosterone plays a big role in male development by turning baby boys into pubescent boys, and in adulthood it makes muscles and semen happen. There’s no clear evidence that testosterone contributes to variation in aggression between individuals, but it’s likely to contribute to differences in aggression between the sexes [1], and there’s really good evidence that it helps you build big muscles[2,3]. Cortisol, contrary to popular belief, doesn’t cause stress, it’s just a response to stress: when your body senses that it’s in need, cortisol increases the amount of glucose in your bloodstream so your cells can have greater access to energy.

In general, hormones like testosterone and cortisol are dynamic. Both hormones have a diurnal rhythm, which means they change throughout the day. They’re also influenced by dozens of variables: the obvious ones like age, sex, and weight help determine clinical guidelines for what “normal” levels look like. One big problem here, though, is that if you look at men from different populations, such as hunter-gatherers, their absolute levels of both testosterone[4] and cortisol[5] are sometimes almost half of those found in American men.

Why is all this relevant to power posing? Well, there are three main points to be made: (1) hormones have complicated effects on behavior, (2) hormones often change throughout the day, and (3) the density and affinity of hormone receptors are potentially just as important as absolute hormone levels (excellent evidence here). How did Cuddy and colleagues control for these phenomena? In short: they didn’t. They took two saliva samples, prior to and following the manipulation, and attempted to control for diurnal rhythm by scheduling testing in the afternoon – a massive six hour window that stretched from 12:00pm-6:00pm. Due to the dynamic nature of cortisol, the standard cortisol assessment protocol generally involves something like two samples a day for 2-3 days. This means cross-sectional samples, like the one in the power posing study, must be analyzed with a grain of salt.

The best way to address the question of whether or not changes in hormone levels caused by the treatment are in turn causing a change in behavior is to run a mediation analysis. This is a method in which you try to test causality among three variables; in this case, you’d want to see that changes in hormones are mediating, meaning causally linking, high-power poses to more confidence. You don’t necessarily need to know all the details of this method (more info here), but the basic point is that the authors, for some reason, do not include this simple test in their paper. Without knowing what people’s hormonal profiles look like (by taking several samples across many days), it’s really hard to say whether or not you’re measuring a “trait” difference or a “state” difference.

A long-running debate in my field is the relationship between statistical significance and biological significance. Even if this treatment did cause significant changes in hormone levels (which the DataColada folks suggest we should doubt), we’re still left with open questions: does this treatment have any biological significance and if so, what are the proximate mechanisms? Even if we see differences in confidence level post-treatment, can we really say it’s because of hormonal changes?


  1. quiscalus
    Posted May 10, 2015 at 10:59 am | Permalink

    Much appreciated if not fully comprehended (Statistical analysis is not my strong suit). There seems to be a bit of a weakness in the TED talk model, where one gets to speak if they can put on a good show, whether it actually amounts to anything in the real world isn’t taken in to consideration (power speaking?) Perhaps it’s gotten to unwieldy to be what it started out or attempted to be.

    • Posted May 10, 2015 at 11:04 am | Permalink

      I think one reason Cuddy’s video got so many views is that she brings in a personal story at the end, and people who advise others how to give TED talks always say “make it personal.” Cuddy talks about her accident, and it’s clear she was deeply affected by her injury and diagnosis, coming close to tears. That surely moved the audience, as her story is not just an impersonal scientific observation.

      • quiscalus
        Posted May 10, 2015 at 11:34 am | Permalink

        Agreed. TED is a great format for strong storytellers. But, so is the Moth radio hour, or This American Life. I’ve been moved to tears by stories in all three. But is that TED was supposed to be, or is that just what it’s become? Perhaps it’s just growing pains, like with the TEDx kerfluffle you have written about in the past. or, I guess the real issue is that if I want science, then I need to get back into the university; degrees don’t finish themselves!

        • Posted May 10, 2015 at 12:01 pm | Permalink

          No, I don’t think that’s what Ted was supposed to be–it’s what it’s become. Remember, though, that TED stands for “Technology, Entertainment, Design”. But I think you can entertain by simply being a good speaker with a compelling talk.

    • Matt
      Posted May 11, 2015 at 11:58 pm | Permalink

      TED has always felt like the science section of a newspaper to me. The main goal seems to be for them to tell a good story that people can repeat at dinner parties.

      Most of the topics are distortions of bad or unproven research (if even that) but end up as sort of modern day proverbs for intellectuals.

  2. Jeff Rankin
    Posted May 10, 2015 at 11:31 am | Permalink

    The link to Dorsa’s page goes is borked (goes to and needs to be de-borked.

    • Posted May 10, 2015 at 11:36 am | Permalink

      will fix

    • Posted May 10, 2015 at 11:37 am | Permalink

      Sorry, if it’s in her intro, the page works for me. Which link are you talking about?

      • Jeff Rankin
        Posted May 10, 2015 at 12:00 pm | Permalink

        Hey it works now! That’s odd. It was the personal site link.

  3. Posted May 10, 2015 at 11:44 am | Permalink


  4. Diana MacPherson
    Posted May 10, 2015 at 11:52 am | Permalink

    Great post! I always did wonder if the Wonder Woman pose was BS.

    There is so much talk about body language that I find myself way too self conscious in meetings. Having come from a very alpha corporate culture, I was always afraid to appear submissive but damn it, I want to sit in comfort!

    • quiscalus
      Posted May 10, 2015 at 12:21 pm | Permalink

      I do wish this kind of thing actually worked. It would have come in handy in my failed attempt at student teaching (it’s like that job interview she talks about, only one that lasts for 4 months but the interviewers openly defy and despise you). I’d love a “power pose” that would trick my mind into feeling confident and trick my body into not sweating through my undershirt, shirt, sweater, and coat before I’d even left the house! Then again, I’m not sure there’s much that a pose can do to alter the self esteem and self confidence of someone with serious anxiety problems. The cold hard facts are that you can’t student teach, get a job, or go on dates if all you want to do is curl up in the fetal position in bed behind closed doors.

    • quiscalus
      Posted May 10, 2015 at 12:23 pm | Permalink

      and as for your wonder woman pose, perhaps it only works if you’re wearing indestructible bracelets, a tiara, and a lasso of truth. (and I’ve got that damn tv theme song stuck in my head now. thanks)

      • Heather Hastie
        Posted May 10, 2015 at 1:29 pm | Permalink

        There are times when it has the opposite effect to the one you want anyway. There are plenty of times when a less confident person finds a more confident person threatening, and their career/relationship/likelihood of getting a job/whether they like them etc. suffers accordingly.

  5. Adrian Johnson
    Posted May 10, 2015 at 12:23 pm | Permalink

    I think this refutation should be presented as a TED talk: then we’d know they took science seriously.

  6. Jeff Rankin
    Posted May 10, 2015 at 12:26 pm | Permalink

    Interesting post, and nice job the explaining the good vs. bad p-curves.

    Has there been any response from Amy Cuddy or additional attempts to replicate her findings?

  7. bluemaas
    Posted May 10, 2015 at 12:27 pm | Permalink

    Very informative and so useful, Ms Amir. Thank you for this effort in your post.

    Now, how does the average bee decompose in her workplace, and within society as a whole for that matter, the sequelae with which such a true data – UNsupported TED talk deludes us of The Masses / us All … … to this voluminous magnitude?

    Will you yourself then, Ms Amir, please be presenting such a bupkas – debunking TED talk soon?


    • dorsaamir
      Posted May 10, 2015 at 12:55 pm | Permalink

      Hi Blue,

      Thanks for the kind note.

      As far as scientific misinformation goes, I feel like someone doing silly poses in a bathroom prior to an interview is definitely less bad than someone, say, choosing not to vaccinate their kids. But in any case, I agree with you that it’s hard to change people’s minds once they’ve been convinced. On a proximate level, it includes conversations and articles like this. But on an ultimate level, I hope foundations like TED and the media in general become more science and stats proficient so that they can better discriminate between well-supported and not-so-well-supported claims.

      If TED invites me to give a counter-talk, I’d happily accept 😉

      • Mark Sturtevant
        Posted May 10, 2015 at 2:22 pm | Permalink

        There are a lot of interesting related things that one could consider.
        For example, even if a power pose (or other body language signals) has no significant effect on the confidence levels of the poser, shouldn’t it effect those to whom it is being directed? For example being in a face off with the 2nd person on left (who is leaning over the table, hands perched high). To me, that posture exudes confidence from that person and in the right context it could convey a bit of a threat. This would certainly get my full attention and, and maybe my testosterone levels would drop a bit.

        • infiniteimprobabilit
          Posted May 11, 2015 at 3:12 am | Permalink

          On the other hand, I’m a perverse bastard, and if someone tried that leaning-over pose on me my bloody-minded-obstinacy levels would go through the roof… 😉

          • darrelle
            Posted May 11, 2015 at 8:41 am | Permalink

            Exactly. I think you’d be likely to find a wide range of responses. Mine would be nearly instant eye roll and a strong inclination to categorize the person as someone I don’t need to waste my time on.

            But I am sort of anti authoritarian. The quickest way to get me to oppose you is to play dominance games. Like the hand shake techniques salesman and politicians like to use. Not a good idea.

  8. Edward Clint
    Posted May 10, 2015 at 1:14 pm | Permalink

    Great stuff. Watching the TED video I also thought, what about other emotions and signals? Don’t we also raise our arms in joy, not just power? The people who a lottery or raffle prize neither have nor feel “power” but they do the same pose.

    It also seems like pondering, reflecting, relaxing and empathizing are each reduced to “powerlessness”, as if posture and gesture have but one emotional dimension.

    • dorsaamir
      Posted May 10, 2015 at 1:52 pm | Permalink

      Good point; I can imagine dozens of other reasons why I’d be in one pose or the other.

      While browsing tw****r, I also found this photo of one of her slides at Fresno State (’s a little hard to see, but it’s another example of reductionist & false categorization. Next to testosterone, she’s written “assertive, confident, risk tolerant, willing to compete” and next to cortisol, she’s written “stressed, anxious, fearful, avoidant”.

      And of course, the nice summary at the bottom is “↑ Testosterone + ↓ Cortisol = ↑ Leadership”..

  9. Posted May 10, 2015 at 1:36 pm | Permalink

    Really good stuff; thanks for the post Dorsa. That p-curve analysis is quite damning. I would love to see this type of thing done more in the social sciences.

    Are you familiar with Andrew Gelman’s work on low powered studies? Besides for the biological significance vs. statistical significance issue you point out, there’s the fact that if studies with small sample sizes and noisy measurements report a statistically significant effect, that effect is quite likely to be in the wrong direction and grossly overestimated. See Gelman and Carlin’s nice paper here:

    They have some nice examples in there about highly suspect psychology research with big popular appeal, similar to Cuddy’s work.

    • dorsaamir
      Posted May 10, 2015 at 1:43 pm | Permalink

      Hey Ed,

      Hadn’t heard of that paper; thanks for the link!

    • Posted May 10, 2015 at 3:15 pm | Permalink

      Very true. When the effect is small in a noisy background, and the effect gets smaller -albeit still ‘significant’- with greater samples, you are probably looking at an artefact.
      Stronger, any effect that cannot be amplified one way or another is probably an artefact.

  10. Gregory Kusnick
    Posted May 10, 2015 at 2:44 pm | Permalink

    I’m not familiar with the literature on power-posing, but it appears (correct me if I’m wrong) that the 33 published results surveyed by CCY in their response were all short-term experiments in a laboratory setting.

    Yet the claim in the TED talk is that power-posing affects long-term outcomes in the real world.

    So where are the studies of this purported long-term effect? Has anybody looked at whether (say) power-posing in the bathroom before class has any measurable effect on class participation and/or final grade? Surely that’s the sort of evidence you’d want before recommending power-posing as a life-changing technique of self-improvement.

  11. Posted May 10, 2015 at 3:18 pm | Permalink


  12. Posted May 10, 2015 at 3:42 pm | Permalink

    I’ll admit that I saw the video and took her at her word until now.

    One thing I’m wondering about…what are the chances that posture is irrelevant, but the mental processes that might get coupled with the posture can have positive outcomes? “Fake it till you make it,” I’m pretty sure, has some basis in reality. If adopting a “power pose” serves as a cue for you to rehearse all the positive mental feedback exercises, it could still be something worthwhile.

    So, for example…when you go to the job interview, it still might be worthwhile to take a superhero pose in the restroom before you’re called…as an excuse to psych yourself up for putting on a good act of being just the superhero the interviewer is looking to hire.

    Also, your posture can significantly influence the perceptions of others have about you. Just asses people’s posture and what you think of them to perform your own informal experiment. If you want people to think about you in a certain way, see if there’s a posture that would convey that to you and try to adopt it.

    …or is all this just folk science with no actual foundation in fact…?


  13. Thanny
    Posted May 10, 2015 at 4:26 pm | Permalink

    As it turns out, hormones, like everything else in biology, are kind of complicated.

    That line felt like a justly deserved dig to me.

  14. Derek
    Posted May 10, 2015 at 4:58 pm | Permalink

    Super interesting guest post! I will have to remember this whenever “power poses” pop up into conversation again.

  15. Keith Cook or less
    Posted May 10, 2015 at 5:13 pm | Permalink

    In respect to TED I am more in the entertainment third of their stated goal. For instance, as far as power poses go, all I could think of is the power pose of my 2nd finger on my right hand, verbally I can enhance this expression and feel an added surge of power.
    I enjoyed the lessons of this post and the comments. Thank you Ms Amir, Prof.
    “Hormone Happy Hour” sounds way better than “Power posing”

  16. Steve
    Posted May 10, 2015 at 9:28 pm | Permalink

    I have never watched a TED talk and hope I never will, so I haven’t seen this one. But I think the description is sufficient: “…professor at Harvard Business School.” In my opinion, which should be the opinion of all intelligent people, “business school” is an oxy — whatchamacallit — moron. Business (in our modern corporate age): taking advantage of whoever you can, whenever you can, to the maximum extent you can. School: institution of learning. Those are words that do not go together. Harvard, MIT, Wharton, East Jesus State College, if it’s a business school, it’s a scam populated by grifters who in a perfect world would hang their heads in shame.

  17. Marella
    Posted May 11, 2015 at 2:08 am | Permalink

    Statistical significance is a useful tool, but actual human significance is a completely different thing. With a big enough sample size you can find all kinds of useless things that are statistically significant.

    For me the problem is that these things are so hard to fake. If you’re feeling inferior or powerless, it’s practically impossible to persuade yourself to assume powerful positions. Just as if you’re feeling alienated from someone you can’t easily mirror their pose. It just feels terribly wrong, even deceitful, to try. I also think it would be easy to make yourself look like an idiot, and the effects of power poses in the toilet would wear off pretty damn quick when faced with your supervisor telling you you’re an idiot. In fact it wouldn’t surprise me if the stress involved in using inappropriate poses had a negative effect on

  18. Posted May 11, 2015 at 8:55 am | Permalink

    Thanks for posting. While there are bias problems with the gatekeeper publishing model I’m not at all sure that we’ve solved them by creating so many avenues for publishing. Combine easy access to publishing with a general lack of understanding of stat analysis – even among the people who report on the analysis – and you have to be more and more suspicious of anything you read. I worked with rats and pituitary hormone response to abstinence after addiction and even such basic questions as how living singly in cages alters their hormonal state have never been fully understood. We have to remember that we rarely or never prove anything but deal in confidence and I think that in many cases we should hold that confidence much more lightly.

  19. Posted May 11, 2015 at 5:36 pm | Permalink

    Great post. I also wonder about the causality in this study: even if the hormone levels did change, how can they be sure that it was in response to the posturing and not something else, such as the language used to describe the posture to be taken? If this is a psychological thing, there might be all sorts of verbal or non-verbal cues – of the kind this posturing is supposed to be! – that might effect the subjects. (This could even account for the lack of repeatability.)

    Also, is there a psychological placebo for this kind of thing? Could you benefit by doing these poses believing that they are helping, even if it is the belief and not the poses that help?

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