Natural selection “doing its job”

We’ve argued before that there is no such thing as completely harmless pseudoscience. But some forms more than others can easily entail consequences that are tragically tangible, including death. Medical pseudoscience, to name the most obvious example, can be devastating to both your life and your life savings. And with reported deaths of unvaccinated children, patients with treatable diseases and even healthy users of ‘alternative’ treatments making fairly regular appearances in the news, these stories are in turn a fairly common feature on skeptical social media. If you’re reading this post, chances are that in at least one of the comment threads these stories attract, you will have come across (and perhaps even typed yourself) something along the lines of Here we have it, ladies and gentlement! Natural selection in action!

A close cousin of assertions they had it coming, and serves them right, this variety of thread-fodder combines abject callousness with a misconception of natural selection that rivals even the most clueless creationist: the idea that if we sensible people just look on, we’ll bear witness to natural selection weeding out people who are stupid enough to believe such stupid nonsense, and quite right too. The implication, of course, is that at some point in the future, we’ll be a sturdy race of genuinely sapient Homo who just aren’t susceptible to “woo” anymore. All that’s required to reach this point is that we and our descendents let nature run its course.

Yes, yes, OK, OK, we realise that most people probably don’t really mean it. The natural-selection-doing-its-job guff probably serves primarily as just a quick and cheap means of signalling membership to Team Skeptic. But if solidarity is your sole reason for making such statements, you should realise that in reality you are hurting, not helping, the team image. As such, we feel duty-bound to signal our strong distaste for the sentiment, however non-committal that sentiment might normally be. We’ll start building our case with some scientific objections that arise from an understanding of natural selection itself, and finish up with objections from basic human decency.

Reasons why the statement is probably false

What is natural selection’s “job”, then?

Anyone who knows anything about (biological) selection knows that it doesn’t have foresight, and so it might seem like stating the obvious to say that it really doesn’t have a “job”—a word that is inextricably tied up with goalishness—at all. By “job”, these commenters obviously mean “blind generation of adaptation”, right?

So is it safe to assume that people dying of quackery will—however slowly—produce adaptation?

Natural selection is, to use George Williams’ definition, “statistical bias in the relative rates of survival of alternatives”. It is an inevitable property of populations comprising varying entities whose reproductive rates are causally linked to heritable attributes of those entities. If you have reproducing entities that are different from each other, where those differences correspond to differential reproductive output, you get natural selection…or, more accurately, you are looking at natural selection.

This textbook ‘recipe’ for evolution is, as Peter Godfrey-Smith puts it, “simply a numerical statement describing a mechanism that in the short term does no more than change the distribution of characteristics in a population”. It actually says nothing at all about adaptation; nothing about a source of new variation; nothing about the mode of reproduction; nothing about the criteria by which reproduction is favoured (ie., nothing about the ‘environment’). In other words, it is necessary, but not sufficient, for what we normally think of as evolution: the kind of cumulative change that leads to adaptation.

For proof of principle, consider the following example: I fill a basket with fifty blue balls and fifty red balls. I then decide, on seeing the result, that I want three times as many balls, but that red is twice as good as blue. So for every blue ball, I add another blue ball, and for every red ball, I add two more red balls (ie., I do so with a probability of 1). I am left with a population of 100 blue balls and 200 red balls. The End.

Believe it or not, this is “natural selection in action”, because whether any given ball gets to “reproduce” depends on something inherent to it. Yes, it involves foresight; yes, it lasts for only one ‘generation’; yes, it’s boring as hell, etc. etc. But as far as I can see, it still qualifies as an example of the basic mechanism that characterises selection, according to text-book definitions.

With this bear-bones definition of selection in mind, I’ll now discuss some of the problems facing the quackery adaptation hypothesis.

1) Are people who believe in quackery statistically more likely to die than those who do not?

Remember, natural selection is statistical bias. While people are killed by quackery, the very fact that we hear about this in the news testifies to it being a rare (ie. newsworthy) cause of death. And that is despite the immense popularity of unscientific health treatment. For instance, in 2007, 38.3% of adults in the United States reported having used some form of CAM, with that figure standing at 11.8% for children. In that same year, approximately $11.9 billion was spent by American adults alone on over 354 million visits to CAM practitioners. $2.9 bn of spending on CAM (again, only in the US) was accounted for by homeopathic ‘medicines’ alone.

Of all those who believe in the powers of alternative medicine, is the proportion who die as a result of quackery significant enough not to be drowned out by statistical noise? In biological evolution, the issue of how much extra risk of dying before reproducing that a given gene needs to confer in order to be subject to natural selection is complicated (as illustrated nicely by this fiddly debate on the subject).

It is certainly true that over geological periods, and given large populations, nature has enormous statistical power to ‘pick out’ tiny signals. However, even if all other things being equal there definitely were a statistically meaningful link between belief in alternative medicine and excess mortality, it might well be that such beliefs also make people more likely to behave in ways that could slightly reduce risk of dying. Here are some candidates I can think of:

  • Eat more fruit and vegetables
  • Meditate
  • Make more of an active effort to socialise with like-minded people
  • Have more opportunities (through New Age ‘workshops’/spiritual gatherings etc) to socialise with like-minded people
  • Be more likely to regularly take part in synchronous group activities (like drum circles for instance), which have been shown to do things like reduce pain threshold and induce social bonding effects
  • Exercise more (yoga?)
  • Get more sleep (because of reduced stress levels brought on by all the above?)
  • Have more children
  • Have more like-minded, child-orientated friends to look after their children

(I’m just throwing these ideas out there – I’m not saying that pseudoscience has fitness-enhancing effects, I’m saying that it might do. More on this, and the distinction between baby and bathwater when it comes to pseudoscience, in a future post.)

2) Beliefs are not genetic.

Things like antivaccinationism or a belief in homeopathy are inherited culturally via your social network. Whether or not you are antivax hinges on how you were raised, what crowds you hang out in, the nature of your educational history, and pure chance too, in the sense of coinciding events and whose influence you just happen to fall under at certain moments of susceptibility.

Williams stressed that “[t]he natural selection of phenotypes cannot in itself produce cumulative change, because phenotypes are extremely temporary manifestations.” Biological evolution is able to produce adaptation because of the ‘immortal’ nature of DNA.

Now, there is a massive ongoing debate about ‘cultural evolution’, the study of which sees cultural ‘variants’ as the rough equivalents of genes, since they (or at least representations of them) do survive beyond the destruction of individuals. It would be a mistake to try and summarise the arguments constituting that debate here (there is a huge amount of writing on the subject, which you can easily seek out for yourself), but I will just say that over the course of an MSc on cognitive evolution, I began to feel that the real point of contention is not so much whether culture evolves per se, but rather whether cultural evolution has much explanatory value. Can it—like biological evolution—decipher patterns that are otherwise mysterious, and that cannot be better probed via direct study of the human mind?

Leaving all that aside, there is a fundamental difficulty with the idea that a cultural trait which has evolved over multiple generations could serve as a proxy for ‘weeding out’ in a genetic reproductive sense. Namely, it leaves us with the problem of explaining the initial rise of the trait’s popularity. iIf we say that medical pseudoscience is the product of cultural evolution, we automatically admit that so far, it has not been good enough at killing people to prevent its own spread. Insodoing, we undermine the hypothesis linking quackery with reproductive disadvantage and have to concede that at the population level, the trait may be genetically neutral (or perhaps even slightly advantageous).

It does assume a fair bit of evolutionary theory, but for those who are interested, here’s an excellent recent paper that goes into more detail about the relationship between genetic and cultural fitness.

Some might argue in response that only stupid people take pseudoscience so far that it actually kills them—that *this* is what natural selection is currently in the process of weeding out—and that cleverer people, while they might dabble with a bit of airy-fairy stuff when it suits them, are not liable to get completely and utterly hooked, and will make good health decisions when it comes to matters of life or death. But…

3) Pseudoscience may well not even be linked to low intelligence (which does itself have a significant genetic component).

With so much aggressive anti-science propaganda out there, it is easy for a bright and well-meaning person to be duped by the movement. Steve Jobs is one noteable example.

The most successful pseudoscience preys on cognitive biases and thinking fallacies that are inherent to us all, thanks, ironically, to none other than natural selection. No matter how intelligent or vigilant one is in their thinking, it’s impossible to not succumb to the effects of something like confirmation bias. (Here’s a video looking at a potential evolutionary rationale behind confirmation bias)

In-built cognitive biases represent perhaps the most fundamental reason why the scientific method is necessary in the first place: we need an outside, impartial process that aims to circumvent and compensate for rigged jury that is the human mind. To echo the sentiments of Richard Feynman, there is no one easier to fool than yourself.

4) Is pseudoscience “a trait”?

The quackery adaptation argument tacitly assumes that, say, the antivaxxers come from the same population as the crystal-healers, and the homeopathy afficionados, etc. It’s true that the best predictor of one fringe belief is belief in other fringe beliefs. But the overlap isn’t perfect, which reflects the reality that it doesn’t make sense to think of the pseudoscientific mindset as a simple monolithic attribute. So if there were any underlying genetic components of belief in pseudoscience, the question of the associated statistical bias in survival that these components conferred would become even shakier, implying even more swamping from statistical noise, as we considered these components separately.

As a loose analogy, we might predict that somebody with a complex disease like ALS would turn out to have some of the major genetic risk factors for the disease. And in some cases, we’d be correct. But ALS is not really a single disease. ALS is just the term given to a family of diseases which cluster together within a certain range of physiological symptoms. Each case of ALS is the observable outcome of a unique constellation from an open-ended spectrum of genetic (and environmental) risk factors, with every patient having a unique aetiological profile. Some patients may not present any of the known major genetic risk factors, but rather were unlucky enough to have been born with lots and lots of very minor genetic risk factors that, individually, are not deleterious enough to have been weeded out of the human genome.

Rather than a delineable ‘trait’ that can be thought about in simple selective terms, a pseudoscientific mindset seems to me (if we’re going to assume, without any evidence whatsoever, that it has some meaningful genetic basis) closer to something like ALS. It doesn’t really make sense to think of ALS as ‘a trait’, which (when we’re talking about evolution) really refers to the direct outcome of a gene or small number of genes that is therefore inherited in predictable ways. For anybody who is interested, I wrote more about the genetics of complex disease here. The relevant section is under the heading “ALS Cannot be Cured Naturally”.

Reasons why the statement is just shitty, regardless of whether it’s false

Even if pseudoscientific beliefs were linked straightforwardly to genetically-mediated intelligence, what kind of person would approve of the systematic weeding out of less intelligent people? Intelligence isn’t the only wonderful thing that people can have to offer, and those who are not naturally great problem-solvers are definitely not excluded from skepticism. The nuts and bolts of skepticism are simple rules of thumb for navigating the world, and if you think it’s only possible to successfully teach these rules to people with above-average intelligence, then maybe, just maybe, you aren’t as clever as you think you are. Furthermore, not all people with below-average intelligence are believers in pseudoscientific ideas. (An antivaccination stance, for instance, characterises only a relatively tiny fraction of the population.)

As well as having less than zero value in terms of informing people, the statement does nothing to console, support or inspire. It serves only to colour the skeptic movement as a bunch of misanthropic cynics indifferent to human misfortune and misery. Rather than communicating support for Team Skeptic, it shows an apathy to the movement’s message. After all, why bother to promote skepticism? The endeavour must ultimately be a manifestation of—and subsumed by—a deeper concern for wellbeing, driven by compassion and the conviction that everyone deserves to reap the benefits that you yourself are fortunate enough to reap from a scientific worldview. Twisting this message into one of spite and contempt is perverse as it helps exactly nobody. The only reason for doing so is indulgence in gluttonous superiority, and amounts to using other people’s suffering as a means to stroke your own ego.

Let’s stop being gratuitiously horrible to each other. To combat pseudoscience and misinformation, we have to equip people with the tools they need to spot it. Waiting for natural selection to “do its job” will leave us standing there like lemons – it won’t work and, in our view, the idea just serves to brutalise people. It is parasitic on, and not part of, skepticism. Nobody “deserves” to die of measles. And making out that they might do is just shitty, whether you “really mean it” or not.


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