Metablog

This post contains speculation that, even by bloggish standards, is unfounded. Get out your salt shaker. Or buy me access to some cogsci journals.

I’m going to publish this post even though it needs another hour or two of editing, and another fifty of researching, because it’s already getting close to the size where I’ll never finish it.

I’ve been working on my procrastination recently, and as a serendipitous side effect of my unusually consistent effort on it for the past couple weeks, I happened to have not spent as much time as usual practicing piano, reading blogs, watching TV, or playing video games or puzzle games (like Tetris or Sudoku). At the end of that time, I had an unusually productive two days at work, until around mid-afternoon of the second day, when I had finished all of my pressing work and decided to spend a few minutes playing Tetris—despite the fact that experience has taught me that the few minutes would turn into much longer.

Now, there was nothing particularly unusual about my deciding to play Tetris; after all, I am working on my procrastination. But I noticed something quite unusual when I started. I felt a head rush, and a strong one. It was like five shots of espresso, all at once. (Minus the jitteriness.) Now, I’ve never taken cocaine, but I imagine it would feel the same way. I take stimulants for my ADHD, and the feeling was the same, but stronger and immediate.

And it hits me—Tetris gives me a dopamine rush. Of course! That’s why it’s addictive! It’s the same mechanism behind food and sex and cocaine and meth and nicotine!

Dopamine is the basic chemical behind reinforcement learning. Its presence allows you to focus your attention on things, by making them seem more interesting. Its levels determine how salient you find whatever task you’re working on. We’ve evolved to release dopamine in specific situations: when we smell food, when we see an attractive person, when we successfully complete some novel task. Well, sort of. “Novel tasks” seem to include dropping Tetris blocks for some reason.

My hypothesis is that I have low resting levels of dopamine. (This is true in people with ADHD.) Because of this, when I do things that raise my dopamine levels, like Tetris, I get more of a rush than other people do, since the relative difference in dopamine in my brain is much higher than for normal people. People with high dopamine feel overstimulated by Tetris and can’t play for very long. Since sudden rises and drops in dopamine can cause addiction, I’m more susceptible to get addicted to these things. When I stop playing, my dopamine drops, and I start to feel bad. This is withdrawal. I’ve become dependent on artificially high levels of dopamine, and I can’t feel normal except when I’m doing very stimulating things, because my brain has become less sensitive—resistant—to dopamine. It’s exactly like a drug. (Well, most drugs to other nasty things too, and affect dopamine levels much more.) And in the past two weeks of stimulation-abstinence, I’ve gotten over a lot of my resistance to dopamine, and so I’m able to focus better.

People with low resting levels of dopamine, besides finding it easier to become addicted to stimulating games and such, also find it harder to start tasks where the dopamine reward is delayed. For instance, I find some programming projects very exciting, interesting, and rewarding to work on. The dopamine rewards I get for that sort of thing are very high, much higher than Tetris. But they’re also more sporadic (coming and going as I make changes and test them) and delayed (it can take half an hour before I can “get into” a programming project—loading all of the program information into my short-term memory takes time). Because of that delay, it’s a lot harder for me to get started on that kind of task when I’m dopamine-dependent, even though the dopamine reward is greater. And since Tetris is so extreme in the immediacy and consistency of the dopamine rush, there’s very little that can compete with it. When I’m in a bad state, I can’t even do my laundry or pay my bills without herculean amounts of effort.

People with high dopamine are better able to weather the troughs in between interesting and fulfilling tasks, and so find it easier to do things with delayed payoffs. They’re also less likely to become dependent on stimulating tasks, and resistant to dopamine, which exacerbates the problem.

My stimulant meds might have two primary effects. One is to speed up the nervous system, which helps me think more clearly and makes me anxious and fidgety. (Maybe the thinking more clearly part is actually because of the dopamine levels, not sure.) The other is to raise dopamine levels, which alter my response to interesting stimuli. But that effect isn’t immediately noticeable. The changes are long-term, involving decreased susceptibility to addiction, gradual restoration of dopamine sensitivity (because when you don’t experience extreme dopamine lows, it’s easier to not spend *all* your time doing things that lead to extreme highs). Cheap stimulation doesn’t excite you as much anymore (because the relative dopamine difference isn’t as big) so you can more easily override your desire to do those things in favor of things like your job and studying. Or maybe studying and such doesn’t really have anything to do with dopamine? Maybe there are other motivational factors involved, and so dopamine is only used for things like eating and such. But that doesn’t seem likely.

(Incidentally, I’ve been playing Tetris just now to see how it affects my ability to concentrate on writing. It appears to not be having a big effect. This could be because my brain isn’t as dependent on dopamine at the moment because I’ve been less stimulated lately. (That doesn’t fit with the evidence that today at work I read blogs for just a few minutes and then couldn’t concentrate the rest of the day.) Or it could be that my medication is wearing off (right about on schedule), lowering my dopamine levels, and so the games don’t raise my dopamine levels to the point where they overwhelm my receptors.)

But if few of the things that we know are good for us are things that we get dopamine rewards for, then is the solution to avoid anything unproductive that gives you a dopamine rush? Cold-turkey on Tetris and video games and everything? What about blogs? Maybe blogs aren’t really a dopamine high, but they’re just attention-grabbing enough so that I can read them when I can’t muster up the energy to do something better.

Many people with ADD react to stimulant medications by becoming calmer. But I’m not hyper when I’m not on my medication. Maybe it’s that I have normal levels of norepinephrine (adrenaline), but low levels of dopamine. Most people with ADHD also have norepinephrine deficits, and most medication blocks the reuptake of both neurotransmitters. That would also explain why I don’t have deficits in goal-planning and organizing, like many others with ADHD, but only with difficulty in initiating goal-oriented behavior (i.e. apathy), and the compulsive seeking out of stimulating activity (i.e. Tetris addiction). So if I find a medication that only blocks the reuptake of dopamine, I might see a much better response.

The dopamine receptors of people who get over cocaine addiction never return to their previous levels. I wonder if the same applies to other addictions.

I wonder how people would be different if their level of dopamine were always exactly the same, if they didn’t respond to stimuli.

Simon Funk, in an old entry, talks about one theory about ADHD. The idea is that people with the disorder lack the volitional pathway through which they can consciously change the object of their focus. And focus here is at the level of basic perception, not some more abstract thing.

Normals are worse at noticing the probe when it comes soon after the blue letter, presumably because they’re still busy processing the identity of the blue letter. As the probe letter moves further away, this effect diminishes until about 700ms or so at which point the probe is identified with the same accuracy as in the control case where there’s no blue letter to confound the task.

ADHD people respond just like normals (quantitatively as well as qualitatively) except that they don’t get better as the probe moves further away. In effect, once their attention is caught by the blue letter, they can’t switch back to looking for the probe.

I don’t think this is necessarily incompatible with the theory I outline here, but it seems to me that he doesn’t see stimulation addiction as a part of it. But then again, from what I’ve read of the rest of his journal, he doesn’t seem to suffer from stimulation addiction. Or maybe he just has it less severely than me, or has learned to cope much better with it. And of course, there’s no ruling out that ADHD comes in different varieties.

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