Friday, May 22, 2009

Armchair Evolutionary Psychology is Quackery

I haven't read the entirety of this piece of stupidity in (Pseudo)Scientific-American, it was just too painful:

Now, I guess I shouldn't expect much from someone who uses the words "patternicity" and "agenticity", but this was linked over at, and people there seemed to like it. So I think there's some merit in spelling out why armchair evolutionary psychology is woo, plain and simple. Here's a quote:

"[W]e make two types of errors: a type I error, or false positive, is believing a pattern is real when it is not; a type II error, or false negative, is not believing a pattern is real when it is. If you believe that the rustle in the grass is a dangerous predator when it is just the wind (a type I error), you are more likely to survive than if you believe that the rustle in the grass is just the wind when it is a dangerous predator (a type II error). Because the cost of making a type I error is less than the cost of making a type II error and because there is no time for careful deliberation between patternicities in the split-second world of predator-prey interactions, natural selection would have favored those animals most likely to assume that all patterns are real."

The reasoning is silly. Suppose I said: "If you believe the rustle in the grass is an indication of food when it is just the wind (a type I error), you are LESS likely to survive than if you believe the rustle in the grass is just the wind, when it's actually food (A type II error). Both times you get no food, but the in the first case you spent energy and effort that could've been used to look elsewhere. Because the cost of making a type II error is less than the cost of making a type I error, natural selection would have favored those animals most likely to assume that NO patterns are real."

Or, a parody more to the point: "Because I can think of one case where thinking X is better than thinking Y, and the thought that X has property F and the thought that Y has property not-F, it follows that evolution makes it the case that having thoughts with property F is always better and evolution made us prefer them in all cases."

Yes, people say this sort of crap. And get published in Scientific American. And fawned over at It's unsettling.

Let's set the record straight. The argument assumes (in particular, provides *no* evidence) that pattern-forming is in general better or less costly. We know this to be false, because Bayesianism is the true account of ideal rationality. If you don't set your present credences equal to your prior subjective probability distribution conditional on your evidence, and you don't act so as to maximize expected utility, you will be more likely to die. That's a theorem. Sometimes your evidence confirms a correlation, sometimes it doesn't. But picking "all patterns, all the time" as your update rule is not optimal, and therefore we've no reason to *a priori* expect it.

Now maybe we do form patterns more than it is rational to. It would be nice to have an explanation for that. Presumably it's because cobbling together agents that can survive for more than a few seconds is difficult, and evolution had to jury-rig some aspects of our psychology from non-optimal other bits. But pursuing any particular theory of what went on requires looking at the damn facts. We need to know what psychological traits are heritable (if any), we need to know which among them were available in the ancestral population to be selected for, which competed with which, what the selection pressures were, etc. And we don't freaking know any of that.

All right. End of rant. FYI I plan to update the blog on Fridays this summer. And I do genuinely plan on blogging, so check in, say, every Saturday


  1. Michael,

    I think I'm just as frustrated as you are that such intellectually inadequate writing has mainstream respectability. I also think it's ironic that the passage you quote is immediately preceded by:

    "The problem is that we did not evolve a baloney-detecting device in our brains to discriminate between true and false patterns."

    However, in all fairness I am not sure that we are dealing with armchair evolutionary psychology rather than an unhelpful and misleading summary of the results of other people's empirical research. The author of the article does go on to cite a book discussing empirical evidence for the sorts of general claims with which the article is concerned...

    Be that as it may, with friends like the author one doesn't really need the Discovery Institute. What you discuss as the reason to reject the "a prioricity" (see what I did there?) of the passage you quote should lead us to be highly cautious of accepting empirical findings that support similar conclusions. The author apparently ignores the fact that ones performance outside of "the split-second world of predator-prey interactions" can be just as significant (for all we know) to a given individual and/or species gaining evolutionary advantage in a given environment over other individuals and/or species as their performance when it comes to fast-paced and continuously active predator avoidance. This is an especially significant consideration when it comes to animals like our ancestors, who weren't always dependent on hunting and who were relatively high up the food chain. (Theirs was often the split-second world of berry gathering...) And there is no reason to think that the widespread tendency of animals to relocate when startled requires anything as cognitively advanced as the sort of pattern recognition evolved by "our Paleolithic ancestors". My empirical research on house flies suggests that they can do it just as well as humans, if not better.

    Besides, whether an error counts as Type I or Type II depends in part on how one describes the case. Here are two errors:
    (1) Holy shit, it's a lion!
    (2) Holy shit, my path through the savanna isn't uniformly lion-free!
    These could be erroneous reactions to the same situation, but (1) is a Type I error, while (2) is a Type II error. Therefore, etc.

    What the article fails to discuss altogether is how "patternicity" and "agenticity" have become so tangled up. From the armchair, one might expect them to be in conflict - perhaps to see agency in a being one must notice deviations from patterns one noticed in it initially, which serves as a stepping stone to seeing complex second-order patterns. If something like the above conjecture is true, then the cognitive pressure to find patterns might have counteracted (at least to some extent) the ability to ascribe agency. Even if, when it comes to beings like oneself, agency gets ascribed through noticing the enormous degree of similarity to oneself, it would leave unexplained the fact that agency gets ascribed to all sorts of things (and in some belief systems to virtually everything) that are very different from the members of one's tribe and/or species. A fortiori, it would leave unexplained why ascribing it to beings other than the other members of one's species, as well as, perhaps, other cognitively advanced animals, stuck with us through natural selection. And certainly nothing in the article suggests that we are in position to draw conclusions about the relative weight and modes of interaction of "agenticity" and "patternicity", which we presumably would need to answer the above questions.

    I certainly don't wish to suggest that we can answer these questions from the armchair. Perhaps we will never even be in position to get conclusive answers through empirical means. But hey, I take a pretty dim view of the intellectual rigor of much of Dawkins's following, so their positive response to this stuff doesn't surprise me one bit...


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