pjeby comments on The usefulness of correlations - Less Wrong

13 Post author: RichardKennaway 04 August 2009 07:00PM

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Comment author: pjeby 05 August 2009 02:52:41AM *  1 point [-]

The correlation between smoking and lung cancer is only .7, but that's a very interesting fact.

I wasn't aware that this was considered either psychology or social science; those are the fields towards which the criticism I pointed out was addressed, not medicine. (Medicine has a rather different set of statistics-based, politics-based, and payola-based errors to deal with.)

Correlation's a useful tool when that's all you have; the PCT criticism is that we now have more to go on than that where humans' and other organisms' behavior are concerned, so it's time to become dissatisfied with the old way and get started on improving things.

(Edit to add: WTF? This is the most baffling downvote I've ever seen OR received here, and I've seen some pretty weird ones in the past.)

Comment author: orthonormal 05 August 2009 07:03:30PM 3 points [-]

Really, I'm not hostile to PCT, just skeptical— but given your claims about the predictive power of PCT, and given that it's been studied for 35 years by a large group including several former academics, I think it's fair to ask this: Can you direct me to an experiment such that

  1. PCT makes a clear predictive claim about an observable result
  2. Standard theories of cognition find that claim highly unlikely (either ruling it out or having no reason to pick that behavior out of many other options)
  3. The experiment strongly confirms the PCT prediction
  4. The result has been reproduced by skeptics of PCT, or reproduced in several independent studies by credentialed researchers.

Note the importance of step 2. The results you've so far pointed out to me (can't find them within LW, sorry) concern a person manipulating a dial to keep a dot in the center of the screen while acted on by unknown, varying forces, and a rat varying the pressure on a lever it needs to hold down in response to varying counterforces. Since these are cases in which 'acting like a controller' is a simple strategy that produces near-optimal results, it doesn't surprise other theories of cognition that the agents arrived at this strategy. (I find it quite probable, in fact, that some form of control theory governs much of our motor impulses, since that's a fairly simple and elegant solution to recurring problems of balance, varying strain, etc.) The point where PCT really diverges from mainstream theories of cognition is in the description of cognitive content, not motor response; and that's where PCT's burden of proof lies.

If PCT is as well-developed across levels as you claim (and well-developed enough to make diagnoses and prescriptions for, say, emotional issues), then it should be easy to make and test such a prediction in a cognitive domain. If you can present me with an experiment that clearly meets those four conditions, I'll be very interested in whatever PCT book you recommend. If 30 years haven't produced such results, then that counts as evidence too.

Comment author: jimrandomh 05 August 2009 08:27:11PM *  3 points [-]

2 . Standard theories of cognition find that claim highly unlikely (either ruling it out or having no reason to pick that behavior out of many other options)

'Standard theories of cognition' is a broad class that includes so many conflicting and open-ended models that I'm not sure I could come up with an experiment/experimental result pair that fulfills this requirement, even without the requirement that the experiment actually have that result.

Comment author: orthonormal 05 August 2009 09:00:50PM *  1 point [-]

That's a good point. I'll have to think carefully about what kind of results would constitute a "surprising" result to theories of mind that include basic modeling capacities and preferences in the usual fashion. Any good suggestions for emending requirement 2 would be appreciated.

Comment author: pjeby 06 August 2009 03:55:02AM 1 point [-]

I'll have to think carefully about what kind of results would constitute a "surprising" result to theories of mind that include basic modeling capacities and preferences in the usual fashion.

And when you do, what you'll discover is that none of them really predict anything we don't already know about human behavior, or provide a reductionistic model of it.

What's different about PCT is that it gives us a framework for making and testing reductionist hypotheses about what is causing an individual's behavior. We can postulate variables they're controlling, do things to disturb the values of those variables, and observe whether the values are indeed being controlled by the person's behavior.

For example, if we want to know whether someone's "Bruce"-like behavior is due to a fear of success or a desire for failure, we could artificially induce success or failure experiences and observe whether they adjust their behavior to compensate.

Now try that with the standard cognitive theories, which will only give us ways to describe what the person actually does, or make probabilistic estimates about what people usually do in that situation, rather than any way to reduce or compress our description of the person's behavior, so that it becomes a more general predictive principle, instead of just a lengthy description of events.

Comment author: orthonormal 06 August 2009 09:12:57PM 0 points [-]

OK, excellent; since you assert that PCT has so much more predictive power, I'm sure you can show me many impressive, quantitative PCT-driven experimental results that aren't in a domain (like motor response or game strategy) where I already expect to see control-system-like behavior.

For example, if you could get a mean squared error of 10% in predicting a response that balances ethical impulses against selfish ones (say, the amount that a person is willing to donate to a charity, given some sort of priming stimuli), then I'd consider that good evidence. That's the sort of result that would get me to pick up a PCT textbook.

Seriously, please point me to these results.

Comment author: pjeby 06 August 2009 09:59:09PM 1 point [-]

OK, excellent; since you assert that PCT has so much more predictive power, I'm sure you can show me many impressive, quantitative PCT-driven experimental results that aren't in a domain (like motor response or game strategy) where I already expect to see control-system-like behavior.

For example, if you could get a mean squared error of 10% in predicting a response that balances ethical impulses against selfish ones (say, the amount that a person is willing to donate to a charity, given some sort of priming stimuli), then I'd consider that good evidence.

You've just crossed over two different definitions of "predictive" -- not to mention two different definitions of "science". What I described was something that would give you a "hard", strictly falsifiable fact: is the person controlling variable X or not?

That's actual science. But what you've asked for instead is precisely the sort of probabilistic mush that is being critiqued here in the first place. You are saying, "yes, it's all very well that science can be used to determine the actual facts, but I want some probabilities! Give me some uncertainty, dammit!"

And as a result, you seem to be under the mistaken impression that PCT has some sort of evidence deficiency I need to fix, when it's actually psychology that has a modeling deficiency that needs fixing. How about you show me a genuinely reductionistic (as opposed to merely descriptive) model of human psychology that's been proposed since Skinner?

I only mentioned PCT in this thread in the context of Yvain's request for an example of people making the mistake Richard wrote this post about. And you responded to my criticism of psychology (i.e., it's not a "hard" science) by raising criticisms of PCT that are in fact off-topic to the discussion at hand.

Are you claiming that, if PCT is flawed, then everything in psychology is just jim-dandy fine? Because that's a pretty ludicrous position. Check your logic, and address the topic actually at hand: the complete failure of cognitive-level psychology to come up with a halfway decent reduction of human behavior, instead of just cataloging examples of it.

Otherwise, you are in the exact same position as an intelligent-design advocate pretending that gaps in evolutionary biology mean you don't have to consider the gaps in your own theory, or lack thereof.

Because PCT could be ludicrously wrong, and it would still be a huge advance in the current state of psychology to be able to nail down with any precision why or how it was wrong.

Which is why critique of PCT is irrelevant to this topic: you could disprove PCT utterly, and the given criticism of psychology would still stand, just like disproving evolution wouldn't make "God did it" any more plausible or useful of a theory.

So let's say, for the sake of argument, that I utterly recant of PCT and say it's all gibberish. How would that improve the shoddy state of psychology in the slightest? What would you propose to replace PCT as an actual model of human innards?

Let's hear it. Name for us the very best that modern psychology has given us since Skinner, of any attempt to actually define an executable model of human behavior. Has anyone even tried, who wasn't an outsider to the field?

Comment author: orthonormal 09 August 2009 06:16:32PM *  2 points [-]

I'll give this one last try.

You've given me the two results I mentioned above, in the area of motor response. They sound like good experiments to me: you can take a model with relatively few free parameters, and find that most subjects' behavior will fit that model extremely well for some particular values of the parameters. That is the kind of experiment I'd take as good evidence that control theory operates in motor response. (Incidentally, if you could give me a link to those experiments, I'd much appreciate it.)

You've been claiming for months that this is just the tip of the iceberg, that PCT is able to isolate variables that subjects are controlling in cognitive contexts like belief. I would be very interested in this claim if I saw some evidence for it; fortunately, your claim that PCT is able to diagnose and treat cognitive conditions implies that it's strong enough to do the same kind of experiments as in the case of motor response. So I began by asking for references to such results, and gave an example of the kind of result that would definitely move me to look into PCT.

Experimental verification seems to me like the obvious thing for PCT advocates to do if they're confident in their theory and frustrated by its lack of academic respect. I would therefore find it highly unlikely, given that your claims are true, that in 35 years there hasn't been a single positive experimental result in a cognitive context, of the same form as the "controlling the position of the dot" or "varying the force on the bar" experiments. That you meet my question with outrage, rather than with citations, is thus Bayesian evidence against the validity of PCT.

Are you claiming that, if PCT is flawed, then everything in psychology is just jim-dandy fine?

Nope. I'm just claiming that if PCT doesn't have the kind of evidence it claims, then I probably shouldn't bother investigating it. The problems with mainstream psychology are manifold, but the discipline seems to be making (slow) progress by scientific criteria: Tversky and Kahneman, for instance, were making novel and unexpected experimental predictions that turned out to be correct. If your discipline does that much better than mainstream psychology, there should be some strong experimental results that show it.

I really can't imagine that's too much to ask, and that's why I've made this challenge. Point me to experimental results that validate PCT in a cognitive context, and I'll pick up the textbook of your choice. Keep grandstanding against the very kind of evidence you presented as evidence of PCT in motor response, and I'll have to conclude that you're peddling woo-woo. The ball is in your court.

Comment author: pjeby 10 August 2009 04:04:11AM 0 points [-]

You've been claiming for months that this is just the tip of the iceberg, that PCT is able to isolate variables that subjects are controlling in cognitive contexts like belief. I would be very interested in this claim if I saw some evidence for it.

I take it you skipped reading Marken's references then, since I believe one of the cited papers was on how physicians' errors in prescribing medicine match a PCT model of the situation, but fail to match an intuitive model of how such errors would respond to environmental changes.

You've apparently also been ignoring my repeated mention of time-averaged perceptual variables like "the amount of work I've done today" or "how recently I got laid" - you can have a "feel" for such values, and how they change over time, as well as respond to changes in them. Do you claim to not perceive -- and control -- such variables? Or are you going to say that since "work" and "getting laid" involve physical activity, they are somehow therefore "motor" rather than "cognitive"?

Finally, you seem to have put me in the strange position of a passing physics student being harangued by a young earth creationist, insisting that I prove the age of the universe to your satisfaction, before you will study any physics, whereas I assert that if you were to go and study some physics, it will be obvious to you why YEC-ism is wrong.

But after being harangued at some length, I relent and attempt to begin with some basic equations, which you then argue are not in the Bible and thus not valid evidence. It is at this point, I begin to question who you're trying to convince by your diatribe, and why, if you genuinely want to learn something, why you're spending more time writing than reading. Don't you have a library anywhere near you?

Keep grandstanding against the very kind of evidence you presented as evidence of PCT in motor response, and I'll have to conclude that you're peddling woo-woo.

I'm not sure I follow you here, since I've only referred to neuroanatomy evidence -- i.e. evidence from a "hard" science. You may be confusing me with one of the other PCTers here who've been talking about the joystick perception experiments, which I consider only relevant for debunking Skinner... which isn't really as useful as it used to be.

Comment author: orthonormal 11 August 2009 03:35:10AM 1 point [-]

I take it you skipped reading Marken's references then, since I believe one of the cited papers was on how physicians' errors in prescribing medicine match a PCT model of the situation, but fail to match an intuitive model of how such errors would respond to environmental changes.

OK, that does sound like a result of the type I'm looking for. I think I can find "Error in skilled performance" at my campus library. In the meantime, could you tell me if the following are true in your opinion:

  1. R.S. Marken is a respected researcher in the PCT community, not a fringe figure.
  2. You (P.J. Eby) have read this paper and approve of the methodology.
  3. The results of this paper constitute strong evidence for PCT for an open-minded skeptic who hasn't read the rest of the PCT literature.

Thanks.