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by wastra 3160 days ago
I agree. And they don't even show there was a decline in their initial experiment on which their entire chain of reasoning is based:

control group glucose before: 102+/-21, after 103+/-18 intervention glucose before: 107+/-21, after 101+/-18 (+/-SD)

Wide confidence intervals, and critically important to note, the pre-test intervention baseline of 107 is much higher than all the other numbers. They do not show that this is not by chance, i.e. null hypothesis of no difference is not rejected. They don't state a P-value (even though this is now out of vogue, the paper is ten years old), likely because it is greater than the mythical 0.05.

These numbers are laughable, so much so that I do not even think they are fabricated. They also quote two decimal places even though their SD is ~20! Every detail of this paper is amateurish.

I also have a problem with the ethics of this study. They recruited students and paid them in course credits. This strikes me as being coersive.

I'm sure I could find more gaping holes in their reasoning, statistics, but I hope I've already shot it down. I'm not a neuroscientist by any means, but I do digest a lot of scientific papers. My guess for a real cause of this effect would be neurotransmitter depletion in key neurons involved in self-discipline.

1 comments

>My guess for a real cause of this effect would be neurotransmitter depletion in key neurons involved in self-discipline.

Thanks for your detailed refutation of this article. I pinboard'd the article, then read your comment, and un-pinboard'd it.

Your guess for the real mechanism is a depletable neurotransmitter. It brings up the matter of discipline - is it a consumable resource, or a buildable resource?

I think traditionally most people think of discipline/self-control being a limited resource. In the course of my own life, trying to manage habits( example, strength training, eating healthily) I find the less I have to rely on at-the-moment willpower, and more on habit, the more adherence I demonstrate. That leads me to think that discipline is a (precious) limited resource.

On the other hand, was listening to a Jocko Willink podcast episode this weekend, and he claims that exercising discipline leads to further capacity for more discipline.

I don't totally reject his idea, but it implies there isn't a limited neurotransmitter, but more some kind of positive feedback loop.

Truth is probably some kind of murky combination I suppose.

From what I understand, behaviorally there are two systems. There's active management, i.e. exerting willpower, and there's habitual behavior, i.e. doing what you usually do.

In the same way that "You" are not a monolithic entity, "You" don't pay attention to everything - take the old "think about your breathing" troll, which causes a redirection of attention to an otherwise autonomous function.

In this world, the role of "willpower" is in habit formation - doing something routinely enough that you train 'yourself' to do it automatically. So exercising this ability can help you train yourself to do it more easily - you're meta-training yourself to train yourself.

But the active exercise of will is by no means energetically free, and that's the origin of the original paper's hypothesis. I'd guess that this exercise of will is not especially amenable to alteration beyond gross physical trauma, but I don't think it has much to do with blood glucose.