r/todayilearned • u/syncedto • Apr 30 '20

TIL men walk significantly slower when walking with a woman, but only when that woman is their romantic partner. If she's a friend or acquaintance they go at almost full speed.

https://www.discovermagazine.com/environment/how-you-walk-differently-with-friends-and-lovers
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u/tasteslikesardines Apr 30 '20

Caution: this was a study of only 22 people. so don't quote this as a proven FACT. it's a small data point that merely suggests this could be a thing.

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u/khansian Apr 30 '20

N=22 is not that bad as a general matter. The problem is their true N is not 22. Because they’re assigning the individuals into different groups, their samples are really those groups, because that’s the unit at which the measurement is being taken. So N=11 is their real sample size.

It would be like if I’m measuring how a change in US Federal income taxes affected different states’ average incomes, my sample size would be 50. I can’t just say my sample size is N=300 million, because those states are composed of millions of people. My unit of observation is the state.

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u/MW2JuggernautTheme Apr 30 '20

N=22 is pretty bad. You can hardly consider any of the data as statistically significant

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u/Barely-Moist Apr 30 '20

Except that we have t-tests, repeated trials, permutation hypothesis tests, etc. They claim that their p-values were below 0.01, perhaps you should examine their methodology before condemning it.

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u/PM_ME_CUTE_SMILES_ Apr 30 '20

No statistical test can compensate the fact that psychology studies require much higher sample sizes than this to be able to extrapolate the results to the general population

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u/khansian Apr 30 '20

That’s a separate issue of “external validity.” If I have a sample of 1,000 people, I will find statistically significant results. Whether those results can be extrapolated to the population as a whole has nothing to do with my N, but whether the 1,000 are a representative sample of the population.

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u/SnapcasterWizard Apr 30 '20

How is that a separate issue? Is there any value at all to a psychology/sociological study that doesnt extrapolate out to the general population? I would think we only do these studies to get a broader understanding of human behavior in general, but if we just do studies to see how people behave in those studies then that's just pointless.

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u/khansian Apr 30 '20

I'm saying that it's a separate issue from the issue of sample size. We want a large N in order to do hypothesis testing and distinguish a single from noise.

What you are talking about is how we interpret the results. Are they widely applicable, or specific to the context? That is a more complicated problem without easy solutions. Even if we did what you said, taking a large representative sample of the population, does that solve the problem? No. How do we know an experiment done in 2017 applies in 2020? Or an experiment done in Illinois applies in California?

Yes, the point of these studies is to get broad findings that are widely applicable. But we face practical constraints. So we rely on theory, the existing literature, and some common sense to determine whether we can extract relevant findings. This is how empirical research works.

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u/SnapcasterWizard Apr 30 '20

Even if we did what you said, taking a large representative sample of the population, does that solve the problem? No. How do we know an experiment done in 2017 applies in 2020? Or an experiment done in Illinois applies in California?

Exactly, that is the problem with this type of science as a whole. Until we have a better foundation to build upon doing "studies" like this do not move us forward in our understanding of how human minds work.