> To better understand fatigue, Pessiglione, Chib and other researchers are trying to bridge an understanding of its biochemical workings with how it affects motivation4. The current hypothesis: cognitive fatigue arises from metabolic changes in parts of the brain that are responsible for cognitive control

This will be interesting to see because for a long time there's been a lot of work saying that "ego depletion" isn't a thing[0] and I swear I have tried to believe this but my own personal experience is completely different. Later in the night, and when I'm mentally tired I do experience this: poor impulse control, lowered emotion regulation, the whole shebang. It'll be interesting to see what the basis is for this, because despite taking all that research at face-value I have to say that now after all these years, I can't help but think it must be wrong.

0: though some have claimed that it is a thing if you believe that it's a thing, i.e. it happens to those who believe in it.

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pitched 10 hours ago | parent | next [-]

Physical fatigue is lack of ATP and happens through the day as oxidation builds up. Cognitive fatigue is a build-up of used neurotransmitters that also build up over the day. These two processes interact with each other though where neurotransmitter reuptake uses a lot of ATP. I see that connection between them as ego depletion. If true, the best solution to it is a nap because that will help clear the junk out.

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rdgthree 5 hours ago | parent | prev | next [-]

I think Daniel Kahneman's System 1 (habits, unconscious) and System 2 (learning, "error correction", conscious) are physical systems, and System 2 takes a LOT more energy to run.

So, when you get tired, System 2 leans more and more on the much more energy efficient System 1. So you get behaviors that look like unrestrained habits: poor impulse control, lowered emotional regulation, etc

Edit: I wrote more about this idea if anyone is curious: https://1393.xyz/writing/alzheimers-is-the-symptom-not-the-p...

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plantain 4 hours ago | parent [-]

I love the simplicity of the System 1/2 breakdown - but is there any actual evidence behind it? It seems like such a classic pop-psychology observational deduction of how something might work with no science to prove it.

	▲	rdgthree 3 hours ago \| parent [-]
		In cognitive psychology there's all sorts of evidence that we have two distinct processes, but I don't think anyone has really mapped it to a physical system yet. Modeling two physical systems is pretty interesting though because dementia ends up looking like a clear failure of System 2. Really neat idea generator even if imperfect.

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IsTom 11 hours ago | parent | prev | next [-]

I feel there is more than one type of mental fatigue. Some of them can be forced through (e.g. the emotional kind that happens when you have to do something you don't want to do) and some can't (e.g. not having enough sleep for prolonged time).

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aswegs8 11 hours ago | parent | prev [-]

Ego depletion isn't a thing if you don't believe in it? Who said that? Dr. Goggins?

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arjie 11 hours ago | parent | next [-]

Haha! Listen, the "you can do it if you believe in yourself" stuff always sounds bogus. But there was some stuff around ten years ago about this. Here's an example: https://www.pnas.org/doi/full/10.1073/pnas.1313475110#F1

	▲	DiscourseFan 11 hours ago \| parent [-]
		I don’t think its completely bogus. There are lots of things you can do that you don’t realize you can. But 40-50 hours of work a week, even if you don’t even leave your house, still takes a lot out of you.

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monoidl 4 hours ago | parent | prev [-]

Also when I last checked, "willpower as a finite resource isn't a thing" was simply the scientific consensus

But I agree that doesn't necessarily translate to "willpower is infinite"