comment by Sandi ·
2017-07-31T20:25:23.416Z · LW(p) · GW(p)
What would be the physical/neurological mechanism powering ego depletion, assuming it existed? What stops us from doing hard mental work all the time? Is it even imaginable to, say, study every waking hour for a long period of time, without ever having an evening of youtube videos to relax? I'm not asking what the psychology of willpower is, but rather if there's a neurology of willpower?
And beyond ego depletion, there's a very popular model of willpower where the brain is seen as a battery, used up when hard work is being done and charged when relaxing. I see this as a deceptive intuition pump since it's easy to imagine and yet it doesn't explain much. What is this energy being used up, physically?
Surely it isn't actual physical energy (in terms of calories) since I recall that the energy consumption of the brain isn't significantly increased while studying. In addition, physical energy is abundant nowadays because food is plentiful. If the lack of physical energy was the issue, we could just keep going by eating more sugar.
The reason we can't workout for 12 hours straight is understood, physiologically. Admittedly, I don't understand it very well myself, but I'm sure an expert could provide reasons related to muscles being strained, energy being depleted, and so on. (Perhaps I would understand the mental analogue better if I understood this.) I'm looking for a similar mechanism in the brain.
To better explain what I'm talking about, what kind of answer would be satisfying, I'll give you a couple fake explanations.
- Hard mental work sees higher electrical activity in the brain. If this is kept up for too long, neurons would get physically damaged due to their sensitivity. To prevent damage, brains evolved a felling of tiredness when the brain is overused.
- There is a resource (e.g. dopamine) that is literally depleted during tasking brain operation and regenerated when resting.
- There could also be a higher level explanation. The inspiration for this came from an old text by Yudkowsky. (I didn't seriously look at those explanations as an answer to my problem because of reasons). I won't quote the source since I think that post was supposed to be deleted. This excerpt gives a good intuitive picture:
My energy deficit is the result of a false negative-reinforcement signal, not actual damage to the hardware for willpower; I do have the neurological ability to overcome procrastination by expending mental energy. I don't dare. If you've read the history of my life, you know how badly I've been hurt by my parents asking me to push myself. I'm afraid to push myself. It's a lesson that has been etched into me with acid. And yes, I'm good enough at self-alteration to rip out that part of my personality, disable the fear, but I don't dare do that either. The fear exists for a reason. It's the result of a great deal of extremely unpleasant experience. Would you disable your fear of heights so that you could walk off a cliff? I can alter my behavior patterns by expending willpower - once. Put a gun to my head, and tell me to do or die, and I can do. Once.
Let me speculate on the answer.
1) There is no neurological limitation. The hardware could, theoretically, run demanding operations indefinitely. But, theories like ego depletion are deceptive memes that spread throughout culture, and so we came to accept an nonexistent limitation. Our belief in the myth is so strong, it might as well be true. The same mechanism as learned helplessness. Needless to say, this could potentially be overcome.
2) There is no neurological limitation, but otherwise useful heuristics stop us from kicking it into higher gear. All of the psychological explanations for akrasia, the kind that are discussed all the time here, come into play. For example, youtube videos provide a tiny, but steady and plentiful stimulus to the reward system, unlike programming, which can have a much higher payout, but one that's inconsistent, unreliable and coupled with frustration. And so, due to a faulty decision making procedure, the brain never gets to the point where it works to its fullest potential. The decision making procedure is otherwise fast and correct enough, thus mostly useful, so simply removing it isn't possible. The same mechanism as cognitive biases. It might be similar to how we cannot do arithmetic effortlessly even though the hardware is probably there.
3) There is an in-built neurological limitation because of an evolutionary advantage. Now, defining this evolutionary advantage can lead to the original problem. For example, it cannot be due to minimizing energy consumption, as discussed above. But other explanations don't run into this problem. Laziness can often lead to more efficient solutions, which is beneficial, so we evolved ego depletion to promote it, and now we're stuck with it. Of course, all the pitfalls customary to evolutionary psychology apply, so I won't go in depth about this.
4) There is a neurological limitation deeply related to the way the brain works. Kind of like cars can only go so fast, and it's not good for them if you push them to maximum speed all the time. At first glance, the brain is propagating charge through neurons all the same, regardless of how tiring an action it's accomplishing. But one could imagine non-trivial complexities to how the brain functions which account for this particular limitation. I dare not speculate further since I know so little about neurology.
Replies from: ChristianKl, IlyaShpitser, Lumifer, gjm
↑ comment by ChristianKl ·
2017-07-31T21:20:38.451Z · LW(p) · GW(p)
I don't think either of those explanations is true but writing out my alternative theory and doing it full justice is a longer project.
I think part of the problem is that "hard mental work" is a category that's very far from a meaningful category on the physical/neurological level. Bad ontology leads to bad problem modeling and understanding.
↑ comment by Lumifer ·
2017-07-31T21:00:15.921Z · LW(p) · GW(p)
The question about willpower depletion is different from the question about mental fatigue and you tend to conflate the two. Which one do you mean?
↑ comment by gjm ·
2017-08-07T14:41:53.784Z · LW(p) · GW(p)
I have a hazy memory that there's some discussion of exactly this in Keith Stanovich's book "What intelligence tests miss".
Unfortunately, my memory is hazy enough that I don't trust it to say accurately (or even semi-accurately) what he said about it :-). So this is useful only to the following extent: if Sandi, or someone else interested in Sandi's question, has a copy of Stanovich's book or was considering reading it anyway, then it might be worth a look.