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Low-power pose

“The samples were collected in privacy, using passive drool procedures, and frozen immediately.”

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Anna Dreber sends along a paper, “Assessing the Robustness of Power Posing: No Effect on Hormones and Risk Tolerance in a Large Sample of Men and Women,” which she published in Psychological Science with coauthors Eva Ranehill, Magnus Johannesson, Susanne Leiberg, Sunhae Sul, and Roberto Weber.

I can’t find a copy of the paper online but here’s the Open Science Framework page for the project, and here’s how the paper begins:

In a growing body of research, psychologists have studied how physical expression influences psychological processes . . . A recent strand of literature within this field has focused on how physical postures that express power and dominance (power poses) influence psychological and physiological processes, as well as decision making . . . Carney et al. found that power posing affected levels of hormones such as testosterone and cortisol, financial risk taking, and self-reported feelings of power in a sample of 42 participants . . .. We conducted a conceptual replication study with a similar methodology as that employed by Carney et al. but using a substantially larger sample (N = 200) and a design in which the experimenter was blind to condition. . . .

And here’s what they find:

Consistent with the findings of Carney et al., our results showed a significant effect of power posing on self-reported feelings of power. However, we found no significant effect of power posing on hormonal levels or in any of the three behavioral tasks.

I just have a couple of statistical comments:

1. Ranehill et al. write, “Our statistical power to detect an effect of the magnitude reported by Carney et al. was more than 95%.” Sure, but a key principle of design calculation (my preferred term, because I think that conventional “power” is unduly focused on statistical significance) is to hypothesize effect sizes using external information, not to simply use a published point estimate that is highly vulnerable to noise and selection.

I’m not saying Ranehill et al. did anything wrong in their analysis here, it’s just that it should be no surprise that this purportedly high-power study did not replicate, as the assumed power is coming from a biased and noisy effect size estimate.

2. After the non-replication, they write, “It is possible that subtle differences between the experimental protocols in Carney et al. and those in our study, originally designed as an extension of Carney et al., led to the omission of factors crucial for power poses to influence hormonal levels and behavior.” Let me just emphasize that just about all effects of interest vary across people and across scenarios. But when someone does a noisy study that fails to replicate in a larger sample, I have no reason, in general, to take that first result seriously.

By the way, in case you’re wondering, no, Anna Dreber is not some sort of a professional skeptic. The papers listed on her webpage include:

Apicella, Coren L., Anna Dreber & Johanna Möllerström. “Salivary testosterone change following monetary wins and losses predicts future financial risk-taking.” Psychoneuroendocrinology, 39: 58-64.

Rand, David G., Anna Dreber, Omar Haque, Rob Kane, Martin A. Nowak and Sarah Coakley. “Religious Motivations for Cooperation: An Experimental Investigating using Explicit Primes.” Religion, Brain and Behavior, 4(1): 31-48.

Dreber, Anna, Christer Gerdes and Patrik Gränsmark. “Beauty Queens and Battling Knights: Risk Taking and Attractiveness in Chess.” Journal of Economic Behavior and Organization, 90: 1-18.

Dreber, Anna, Christer Gerdes, Patrik Gränsmark and Anthony C. Little. “Facial Masculinity Predicts Risk and Time Preferences in High-Level Chess Players.” Applied Economics Letters, 20(16): 1477-1480.

I don’t know if this should make you more or less likely to believe her findings on power poses; my point is just that, unlike me, Dreber is an active researcher in that area.

I wonder if the Ted people will update their webpage? Probably not, eh? If they did, that would be news.

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10 Comments

  1. Chris Pounds says:

    Thank you for your profound post exposing possible power posing posers.

    • Dzhaughn says:

      Pounds personally praises probability Professor’s profound post positing, poo-pooing power-posing posers purported power paucity, per p-value pedigree.

      The power of crowd-sourcing, right before your eyes.

  2. Shravan says:

    Were at least the standard errors smaller in the larger study? I always thought that would obviously be true, but it isn’t always so in practice, and this probably has to do with Andrew’s comments about increasing sample size not necessarily being enough of a solution.

  3. Gagan says:

    this isn’t related to the post, but I thought I need to share this groundbreaking finding before someone else claims it: Thomas Merton is actually Professor Gelman sans the hair.

    Check out this power pose:

    http://image.pbs.org/video-assets/pbs/religion-and-ethics-newsweekly/68763/images/Mezzanine_031.jpg

  4. mark says:

    Amy Cuddy’s power pose talk (in which she claims an effect on testosterone) is the second most viewed Ted talk of all time. Over 28 million views.
    http://www.ted.com/playlists/171/the_most_popular_talks_of_all

    And here I get grateful when my papers get mis-cited 100 times.

  5. cheese_d says:

    I hope this isn’t consider OT for a stats blog but: “a design in which the experimenter was blind to condition” <– that is a huge deal. As far as I can tell the two studies may even be considered to be unrelated. One has blinded experimenter(s) and the original simply does not. There is a reason for double blinding medical trials…

  6. Statistaical Trump says:

    More research on power poses..they’re hot!

    Dominant, open nonverbal displays are attractive at zero-acquaintance

    http://www.pnas.org/content/early/2016/03/23/1508932113.abstract?sid=4955b36b-65de-4367-97f2-a10248a7b47b

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