Evolutionary Science and Gresham’s Law of Ideas

So there’s a book that said something really dumb:

And by cursory inspection of excerpts and reviews, it is chock full of all kinds of silly ideas that experienced what I can only imagine to be a frictionless path from the authors’ minds to publication. I don’t really care about this book or the specific ways in which it is is bad. And I don’t really care about the authors, who appear to be mediocre self-styled evolutionary scientists whose major claims to fame appear to be favoring ivermectin over vaccines and supporting themselves financially by levying a lawsuit against Evergreen State College.

What I care about is evolutionary biology and psychology as subfields. The core idea is that the evolutionary framework of persistent adoption and adaptation of traits under unrelenting selective pressures can be a useful modeling framework for generating theories of social, economic, biological, and psychological phenomena. Evolutionary selection is a good idea, one of the most powerful in intellectual history! But to me, an outsider economist with a long-ago acquired undergraduate degree in biology, the subfields seems to be suffocating under the weight of ad hoc theories generated in volume by marginal practitioners and non-scientists. Why? What’s wrong with evolutionary sciences? Here’s a couple thoughts.

1) There’s nothing wrong. Saying something is wrong with the subfields is like watching The Shining and thinking “There’s something wrong with axes”. This is just a bad book with bad ideas thought up by authors with minimal right to claim the mantle of evolutionary science.

That’s a totally reasonable response but I’m in no mood to leave well enough alone.

2) There’s a perverse selective pressure within evolutionary sciences where the worst ideas rise to the level of public dissemination. The culling forces of the popular press select along dimensions that are not merely orthogonal to good science, they are actively selecting against it. Put in the language of my own field, publishing bad ideas seems to be more profitable than publishing good ones.

That’s pretty big claim, and one for which I have no real proof, just tacit intuition and a small number of anecdotes. Sorting through the reviews of the Heying & Weinstein book, I thought of the brief phenomenon that was “Sex at Dawn” a decade ago. It, similarly, sold a breathless explanation of human behavior, specifically promiscuity. Emphasis on the world sold. “Sex at Dawn” proved that you could be scientifically hollow and still sell a boatload of copies. For those who are curious, here’s a review by an evolutionary psychologist that doesn’t hold nearly the grudge that I do. He politely sifts through the major claims, weaving through the silliness to find the handful of specific claims, and proceeds to debunk them. Other reviewers were considerably less kind (including those at Oxford Press, who rejected it for publication).

So why are these and similar books, so successful?

I’ve long suspected that there is a Gresham’s Law of Popular Science at work. Simply put, bad ideas are less costly to generate than good ones, so they are more plentiful. For the non-expert consumer of popular science, this raises the costs of search probability that a randomly encountered book is bunk. What I believe to be more problematic, though, is that bad ideas are often less costly to consume. Spoon-fed as common sense writ magnificent and powerful, pseudoscientific books get a foothold in our mind first through the scarcity of our time and attention only to then grow roots in our ego. Easily consumed during rare moments of relaxed reading, they then show us ideas that give us explanatory access to life, the universe, and everything. Why struggle through caveated niche explorations when someone else has distilled the complexity of a modern life well-lived to something that is as flexible in its flattery as a horoscope and often conveniently enumerated?

Does this happen within economics? Of course it does. It happens in every scientific field. But that is why scientific fields evolve intellectual immune systems, and often very aggressive ones at that. The entire field of “Statistics” essentially exists as the custodian of the scientific method. But there are little details that matter, too.

Take, for example, the core concept of “maximization” in economics. Sure, it gets abused, but at the end of the day it’s pretty tough to get very far with an ad hoc utility/profit/wealth maximizing model in economics that produces useful predictions. Why is that? Well, a big reason is that we’ve left out a very important word. Economists deal almost exclusively in constrained maximization. Absent constraints, nearly every maximizing model amounts to little more than a tautology. It’s requirement for maximization under constraints, both components transparently introduced, that gives a model it’s power. When I observe meritless pop evolutionary science books, mostly what I’m seeing is unconstrained just so stories that work backwards from a conclusion they believe there is a book-purchasing audience for. There are selective pressures, but where are the resource constraints? There are groups but where are the rivals they are competing with? There is this evolutionary path, but why not the other paths?

So what should evolutionary sciences do? Well, first of all, I don’t know. But if I had to guess, the answer is nothing. Nothing but do the thing a proper science always does. Do the work, push the good ideas, kill the bad ones, and trust that the custodians of the scientific method will do their jobs. And so will the editors. And the hiring committees. And the critics. Sure, a couple folks will pay a couple years mortgage, but a bit of financial and status injustice are a small price to pay while we keep the scientific mission moving forward. At least until we’re all crabs.