November 16, 2010

Evolution and the citizen. What about diversity in the human population?

Over at his blog The Loom Carl Zimmer puts forward an open question about evolutionary biology and citizenship.

My task is to discuss “how understanding evolution allows Americans citizens to formulate more informed decisions about societally important matters.” I like this assignment, because it’s an interesting twist on the standard question about the value of evolutionary biology. Typical answers to that question include the cosmic–how it helps us see our place in the history of the universe–and the practical–how it can help in our search for better health and happiness.

The question I’m addressing is a bit different. How does a good understanding of evolution better prepare us to make decisions as citizens?

It's a really tricky question. Judging by the kinds of answers given in the comments at The Loom, it seems difficult to hit the right spot. The answers easily fall into the "cosmic" kind or the "practical" kind, but I'll try to give it a go.

I don't really see a clear distinction between the "cosmic-how-it-helps-us-see-our-place-in-the-history-of-the-universe"-answers, the "practical-how-it-can-help-our-search-for-better-health-and-happiness"-answers and the "preparing-us-to-make-decisions-as-citizens"-answers. Don't they all prepare us to make decisions as citizens? The kind of decisions the "cosmic" answers allow us to make have to do with for instance animal rights, natural conservation and environmental ethics, more global decisions; while the "practical" answers allow us to make decisions regarding things like bacterial resistance, drug response in disease treatment and nutrition, more specific solutions to specific problems. They're all great reasons to make sure we as citizens understand evolutionary biology correctly. But the question at hand seems to do with the decisions that lie in the sphere of civics somewhere between the global and the specific. It's a good question inasmuch as I have never really seen anyone adress it specifically, but I wonder how big that spot really is. It's difficult to tell.

Several answers that have come up have to do with the acceptance of human diversity, and I think there definitely is something to it. Understanding that evolution generates diversity as well as how it generates diversity certainly prepares us to make informed decisions regarding our society, but I have to be very skeptical when it comes to the idea of assigning a "value" to that diversity in itself or to over-interpreting the evolutionary role that any specific part of that diversity might play in the future of humankind and our changing society. I think it's far more concrete than that.

An example: The strong evidence for a genetic basis for ADHD and autism shows that these conditions form part of the "normal" genetic diversity of the human population as generated by evolutionary processes. The fallacy lies in thinking of ADHD and autism, but perhaps also mental illnesses such as schizophrenia, as "abnormal" conditions, "defects" that evolution strives to "purify" the human population of. Instead it seems as though they are "natural" parts of human diversity and exist in different gradients as a result of the genetic variation that evolution has generated. They follow humanity hand in hand. This realization has long-reaching consequences for how we see pedagogy and education policy, for instance, as well as the whole infrastructure of our society, which for the most part is built to conform to the majority. This realization also makes us question the terms "normal" and "natural" when applied to the human population. A proper understanding of evolutionary biology and the patterns of human genetic variation also allows us to address issues of race in a correct way, which I've commented on before, and potentially also questions concerning intelligence, homosexuality, risk-taking and violent behavior, addiction et c.

These are very concrete issues that manifest as specific societal problems, but they sort of also connect with questions of our place within all of the natural variation and in the history of the universe.


  1. Dear Daniel,

    thanks about your post. I'd like to add some thoughts on evolution "striving" to rid humanity of conditions such as ADHS and autism (or rather not doing that):

    My opinion is that while evolutionary mechanisms of course can be applied to the human population, we have to be careful when doing it. Strong forms of autism can be a problem for an individuum living under savannah conditions, and would consequently be a selectable trait that evolution would perhaps "strive to remove" (i.e. it would not take hold in a majority of the population). I find it hard to argue, however, that in our (western,modern) human society, it still is a strongly selectable trait.

    You are saying that it is not a "defect" that evolution strives to purify us from, but a natural element of human diversity. I fail to see the distinction, since each "defect" is part of the natural diversity, as long as it is not introduced in an unnatural way, e.g. by mutagenic substances. And evolutionary principles (as an acting agent :-)) make no distinction between "defects" and "natural parts of variation". Every variation can be a defect under certain circumstances, it's the circumstances that define whether something is deleterious (a defect) or advantagous, or unimportant.

    Insofar it might be helpful to teach citizens about evolution, to make sure they don't see it as "purifying fire" that "weeds out the weak" and is all about "survival of the fittest". Saddeningly, some people use this wrong understanding of evolution to justify what they see as helping evolution, e.g. when cutting back social programmes etc.

  2. Hi Florian! Thanks for commenting.

    I think we're speaking "around each other", as we say in Swedish, but that's OK, I'll just clarify my point.

    I very deliberately wanted to avoid speculating about, as you write, "evolutionary mechanisms... applied to the human population" because like you I dislike those kinds of speculation. I wrote: "but I have to be very skeptical when it comes to the idea of assigning a "value" to that diversity in itself or to over-interpreting the evolutionary role that any specific part of that diversity might play in the future of humankind and our changing society". So I did not at all want to make a point about the actual effect that things like ADHD and autism have on the changing allelic frequencies over time in the human population, because it's not important for the point I want to make. It's almost impossible to argue too because things like these are very polygenic, have dosage effects, trade-offs, and are in general very tricky to unfold genetically.

    So regardless of whether it might be selected for or selected against or not at all or only very very little (which is my own personal opinion), these traits are there and I don't think our evolution so far has done a "bad job" at not removing them. It's simply too complex of a situation to be able to say one way or the other.

    I put "defects" in citation marks for a reason: the word shouldn't be used literally. Like you wrote, what's advantageous or disadvantageous changes, obviously, and in the case of human evolution it's mostly a question of speculative interpretation. The point is that evolution, taken as a whole, gives us diversity. It does NOT, as a whole, strive towards a homogeneous population. Understanding that changes our perpective on traits that are disadvantageous in our societal architecture, or are only interpreted as disadvantageous, but that in actuality are just as "normal" (within citation marks) as any other trait we would usually consider "normal". So people with ADHD or autism are not "defective" in an evolutionary sense, although they might experience difficulties. I think you fail to see the distinction because I only make it in a pedagogical sense and you, being smart, look one step ahead. So we're actually saying the same thing.


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