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Some thoughts on evolution

Transhumanism
No, this is not an Evolution Versus Creationism Death Match. Really, there's only so many times one can watch Godzilla squash Bambi before it ceases to be amusing any more.

Rather, this is a post intended to clear up some popular misconceptions about how evolution works. I've been meaning to write it for a long time, and some comments made at a Dragon*Con panel reminded me that I still haven't ranted about this in my journal. So, it's high time to get my rant on!

There are two popular notions about evolutionary processes that I hear all the time, often from folks who ought to know better, and they tend to get under my skin. The first is that evolution is no longer operating on human beings; the second is that evolution is goal-directed, that it makes a species "better." Ready? Here we go!

Evolution still operates on people, just as it always has

"Evolution is about survival of the fittest," people say. "Today, thanks to the miracles of modern technology, people who would have died a hundred or a thousand or ten thousand years ago can be kept alive. They don't die off, so their genes still spread. So that means we've stopped evolving."

Fine, except that it's wrong. Evolution isn't about survival of the fittest. That wasn't Charles Darwin's phrase; it was coined by Herbert Spencer, and was included in On the Origin of Species only at the fifth reprint, as it had become popular by that time.

But evolution is not, and never has been, abut "survival of the fittest." That's an overly simplistic and inaccurate view of how evolutionary processes work. Evolution is about the propagation of those genes which most enable an organism to...propagate its genes. What's good for the gene is often, but not necessarily, what's good for the organism; a gene that shortened its host's life by fifteen years but increased the probability that its host would reproduce by .01% would do quite well in the evolutionary game.

(As a segue, I've frequently heard an argument against transhumanism in general and life extension in particular that says "Mortality and a finite life expectancy must be good for us. If they were not good for us, then we would not have evolved to have a finite life span. So the fact that we have evolved in such a way means that there is some benefit to being mortal." This argument does not hold water, because the bulk of our evolutionary heritage comes from a time when most members of the species would die through accident, disease, or predation far, far before they would die of old age. A gene that conferred immortality offers no reproductive benefit to a species whose members are killed by leopards, diseases, tumbles off a cliff, or each other before they're thirty. Ergo, such a gene would not be selected in favor of. We have genes that confer mortality because there's no advantage to genetic immortality.)

Evolution is not about survival of the fittest. It's about the genes that spread. Evolution needs only three things to operate, namely:

1. A population whose individuals are different from one another;
2. A system whereby those differences are heritable; and
3. A system whereby those differences make a difference in how likely an individual is to reproduce.

That's it. That' all it needs. And yes, you have those things in humanity. We are not all the same; the differences between us can be transmitted to our children, and sometimes, those differences make a difference in how likely we are to have children, or how many children we have.

Contrary to the crude understanding of evolutionary processes so common in pop culture, it is not necessary for individuals who have a particular trait to die for that trait to be selected against. If a particular gene--a gene making its bearer more likely to have asthma, say--decreases the odds that a person will reproduce by 0.01%, that's enough. If even one person out of ten thousand has one fewer child because of a particular gene, then evolution is still working.

Modern medicine keeps many people alive today who would die in a pre-industrial society. That does not mean that people with detrimental genes have exactly the same number of children at exactly the same rate as people without that gene. As long as a particular gene has any impact on the number of children its hosts have, however slight, evolution still works.

Evolution is not goal-directed

Evolution does not make a species "better" for any value of "better" that people often use. Evolution favors genes that make its hosts more likely to reproduce. That's it. A gene that causes you to die of a horrifying, debilitating cancer after you hit menopause isn't going to be selected against.

Furthermore, evolution is completely blind with regards to "better" and "worse" as human values. At the panel, one person used Down's syndrome as an example of how evolution no longer applies to human beings. If people with Down's, he reasoned, have children, then how can evolution make the human species better?

This question falls down on a number of levels, and shows a lack of understanding of what evolution is. Down's syndrome is not generally heritable; it's caused by a particular genetic malfunction that does not, usually, affect the gametes.

But leaving that aside for the moment, let's assume that it is heritable. What does that mean? If people with Down's syndrome had more children than people without it, then from an evolutionary perspective, Down's syndrome would be "better." From an evolutionary standpoint, there is one and only one definition of the word "better," and that is "more likely to reproduce."

I mean, if you think about it, I am a worst-case scenario. I have not had children at all, and I have even opted for voluntary sterilization, so I never will have any children. My particular collection of genes is a dead end. I am, evolutionarily speaking, the poorest possible outcome. From the perspective of the processes we're talking about, a person who has Down's syndrome and has children is better than I am.

It frustrates me that American culture is so divided and American politics is so wrapped up in the idea of evolution, yet very few people even understand what "evolution" is. They feel passionately about it, but they're incapable of articulating the most basic principles of evolutionary biology.

Rant off.

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Comments

red_girl_42
Sep. 4th, 2007 09:54 pm (UTC)
This is wonderful--thank you! I may have to add this to my memories as it touches on a couple of my own pet peeves about people's "understanding" of evolution.

Another couple of pet peeves of mine:

1. People assuming that if you say that something is an evolved trait, you must also be claiming it's a morally defensible trait. An example of this is when some scientists suggested that rape is an evolved behavior that has allowed men with little access to willing women to propagate their genes anyway. There was a huge feminist uproar about this--not attacking the actual science behind the suggestion, but attacking the idea that anyone would even dare voice this hypothesis. Evolution isn't morally based. Sometimes we evolve in ways that are politically incorrect. I don't think it's really fair that men are on average bigger and stronger than women, but I shouldn't attack scientists who study this and find it to be true. When a scientist tells us what *is,* they aren't telling us what *should* be. Nor are they telling us that we have no choice in the matter. Our genetic makeup isn't the only factor that governs our behavior.

2. Similarly, and also something you touched on...I hate when people assume that an evolved trait is necessarily the ideal one. For instance, people promoting that "hunter-gatherer diet" claim that because we evolved in hunter-gatherer societies, a diet similar to that of our ancestors must be the healthiest one we can eat now. But just because our bodies adapted to survive and reproduce in certain limited conditions, that doesn't mean other conditions can't be even better. It's not like our ancestors had the opportunity to try. Certainly, some products of agriculture/industrialization *are* unhealthy for us, but others (such as access to dairy products, so that pregnant mothers don't wind up losing teeth with every child) are most definitely a good thing. The mother who loses all her teeth in childbearing (because the human body is designed to feed the fetus first, the mother last) is just as much of a reproductive success as today's toothy mom. But I'll take my cow's milk and pearly whites over a gummy stone-age grin anyday.
boigrrrlwonder
Sep. 5th, 2007 12:36 am (UTC)
1. People assuming that if you say that something is an evolved trait, you must also be claiming it's a morally defensible trait. An example of this is when some scientists suggested that rape is an evolved behavior that has allowed men with little access to willing women to propagate their genes anyway. There was a huge feminist uproar about this--not attacking the actual science behind the suggestion, but attacking the idea that anyone would even dare voice this hypothesis. Evolution isn't morally based. Sometimes we evolve in ways that are politically incorrect. I don't think it's really fair that men are on average bigger and stronger than women, but I shouldn't attack scientists who study this and find it to be true. When a scientist tells us what *is,* they aren't telling us what *should* be. Nor are they telling us that we have no choice in the matter. Our genetic makeup isn't the only factor that governs our behavior.

In a society when one of the dominant discourses is "natural = acceptable" (think about how much investment has gone into finding a gay gene and the argument that gay people are born gay as a means to justify gay rights), what good can come from a study that argues that rape is an evolved behavior? Furthermore, a lot of evolutionary biology, when studying humans, often reflects the sexism of our society (for example, how common it is to assert that women want monogamy while men want nonmonogamy in evolutionary biology).
catwoman980
Sep. 5th, 2007 03:41 am (UTC)
Indeed.

The reason I have a problem with the rape=evolution argument is that I, personally, find it to be incredibly lazy science in addition to the fact that the only people I've heard make it are usually rape apologists using it in a really twisted (and usually political) way.
red_girl_42
Sep. 5th, 2007 05:39 am (UTC)
I'm not arguing for or against rape as being an evolved behavior. However, I remember when the book A Natural History of Rape came out, the majority of responses to it read something like, "I haven't actually read this book, but it's offensive and wrong!!1!11!!" If you want to accuse researchers of lazy science, then you need to actually read their studies (the actual journal articles) and analyze their methods using scientific standards. And if you do that and you still decide that the science is shoddy, that's fine, that's exactly how science is meant to work. I have no problem with that. It's the folks who immediately dismiss any research that contradicts their world-view that I have a problem with. That and the folks who read a story about a study in USA Today and think they have any ability to judge its worth based on a 300-word mangling of the science.
catwoman980
Sep. 5th, 2007 05:57 am (UTC)
If you want to accuse researchers of lazy science, then you need to actually read their studies (the actual journal articles) and analyze their methods using scientific standards. And if you do that and you still decide that the science is shoddy,

I have, and I did.

It's the folks who immediately dismiss any research that contradicts their world-view that I have a problem with.

Me too. And the world view of women=passive and men=aggressive/men want lots of partners and women want monogamy/men rape because of evolution! tends very much to come from people who have a very sexist worldview. It influences the science--or lack thereof--and their research and their arguments are poorly constructed.

If you've read peer-reviewed articles that express the whole evolutionary-rape thing well, that's great. I haven't, and I've looked. In addition to that there are a bunch of pseudo-intellectual rape-apologists running around quoting (what I believe is) already shoddy research for political reasons. If there are feminists freaking out on one side, there are just as many, if not more, individuals reading USA Today articles and telling me that--evolutionarily speaking--women prefer pink! It's bad science, bad journalism, and a bunch of sexist jerks saying "It must be true!" without putting much thought into it, because they see the world that way anyway.

Personally, I think complex and interesting discussion can be had on the subject--as well as the subject of evolution vs. environment in general--but it's been abused to much for social or political gain that it's not even a scientific argument anymore. Often, it has more to do with social policy.

Point being, I honestly think we're agreeing. We're both bothered by the same thing (lazy/shoddy science) we're just sitting on opposite sides of the issue (presumably), and I'm merely trying to point out that the evolutionary biology camp has its own group of political opportunists.
catwoman980
Sep. 5th, 2007 05:59 am (UTC)
*So much, not "to" much.
red_girl_42
Sep. 5th, 2007 06:13 am (UTC)
I think we're agreeing, too. As for whether we're sitting on opposite sides of the issue--I never gave an opinion on the issue. ;-) I merely gave an opinion on people who automatically assume that when someone says a behavior is evolved, that they must be saying it's morally acceptable. Replace "rape" with any other human behavior and it's still an incorrect assumption.
catwoman980
Sep. 5th, 2007 06:25 am (UTC)
I think (and
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I think (and <lj-user="boigrrrlwonder"> can correct me if I'm wrong) that the original point was not so much that "evolved" is inherently a moral distinction so much as it is <i>taken</i> as a moral distinction.

Science does not occur in a vaccuum (har). Researchers are just as likely to have political motivations, or social biases, as just about anybody else. The people funding them are often even <i>more</i> likely to have an agenda.

<i>I merely gave an opinion on people who automatically assume that when someone says a behavior is evolved, that they must be saying it's morally acceptable. Replace "rape" with any other human behavior and it's still an incorrect assumption.</i>

I think it's problematic but fair to make that assumption. It's fair because, especially in the west, I think the vast majority of people out there <i>are</i> making a moral judgment. It's problematic because it perpetuates the assumption. The western world, I think, has trouble doing or thinking anything without ascribing some kind of judgment to it--usually moral.
james_the_evil1
Sep. 8th, 2007 11:40 pm (UTC)
The whole pink/blue thing is actually involved in advertising changes in the US in the early 1900's.
Prior to that, pink was associated with boys (as it was a milder version of red which was considered a masculine color due to its link to fire) and blue for girls because it was tranquil and calm like the ocean.
So that particular one's memetics, not genetics, but is still linked to biased views of sex & gender :-)
catwoman980
Sep. 9th, 2007 02:52 am (UTC)
The reference was to an article floating around that claims that girls genetically prefer pink, and boys blue, and that it must be because women were gatherers and were looking for ripe fruit, so their eyes would be drawn to red, so they like pink. It's stupid and wrong on about 98709870868976 levels. The study itself showed that all people tend to be drawn to blues and purples, but that women more often tended to be drawn to purple. And that's more red than blue, so that means women like pink!
james_the_evil1
Sep. 9th, 2007 02:54 am (UTC)
Yup, I'm aware :)
I was just pointing out the idiocy of that given that anyone who's taken a marketing class knows it's a societal construst & only about 100 years old.
catwoman980
Sep. 9th, 2007 03:06 am (UTC)
Ahhh, ok. Sorry if that seemed snippy or defensive. :)
james_the_evil1
Sep. 9th, 2007 03:07 am (UTC)
's cool ;-)
red_girl_42
Sep. 5th, 2007 06:00 am (UTC)
what good can come from a study that argues that rape is an evolved behavior?

I don't think we should limit research subjects (or censor their results) based on what is and isn't politically correct. The good that comes out of any research study is that we increase our knowledge of the world around us, and hopefully our ability to make it a better place. If the evidence bears out that rape is indeed an evolved behavior, then I think it's worth knowing that. It might give us clues to how we can best prevent it, which I think is a very good thing to do. But basically, I think knowing the truth is better than believing in pretty lies. And the only way to get to the truth is to allow all researchers to present their results and state the conclusions they have drawn. And then other folks can look at their methods and repeat their studies and determine if, in the grand scheme of things, the study has merit. If you subjectively censor reearch you don't like then you can't actually determine what is and isn't true.

for example, how common it is to assert that women want monogamy while men want nonmonogamy in evolutionary biology

Actually, in evolutionary biology it's becoming less and less common. And the reason is that numerous studies are coming out showing that females (of many species, including humans) aren't nearly as monogamous-minded as we once believed. For example, genetic tests have revealed that chimpanzee females will risk life and limb (male chimps are very violent) to sneak outside the group and have sex with males from other groups. Again, this is how science works. It's cumulative. No one study provides a definitive answer to questions, but you can't get a clear picture of what's going on unless you have access to all the studies available and the ability to study, repeat, and improve on their methods.

You might say, "What good can come from a study that argues that rape is an evolved behavior?" But there are plenty of conservatives out there who might say, "What good can come from a study that argues that reproductive freedom is good for women?" No matter what you study, someone will be opposed to your results. Which is why everyone needs to be free to publicize their results, instead of letting political opinions squelch them.
tacit
Sep. 5th, 2007 03:13 pm (UTC)
In a society when one of the dominant discourses is "natural = acceptable" (think about how much investment has gone into finding a gay gene and the argument that gay people are born gay as a means to justify gay rights)...

I don't think that the idea that sexual orientation is genetic is necessarily about "justifying gay rights." Frankly, I think a stronger case for gay rights can be made simply on the basis that people's private choices are not, and should not be, a matter of public policy, and that equal protection under the law is not meaningful if it doesn't apply to everyone.

Nevertheless, I do strongly feel that the pursuit of knowledge, of and by itself, has value. We are physical creatures; we operate in accordance with the laws of physics; our behaviors are rooted in our brains, which are physical organs shaped by our genes and our experiences. If sexual behaviors are influenced by genetics, that's something that's worth knowing about.

Anything we can learn about ourselves has value. The truth has value. Understanding ourselves better is important; it is knowledge that counters ignorance and superstition.

"...what good can come from a study that argues that rape is an evolved behavior?"

If it is true, then knowing that it is true has value.

People may misuse this kind of knowledge to attempt to justify violence and rape. This is not an argument against learning whether it's true that rape is an evolved reproductive strategy, because the people who would use this to try to justify it have already decided that rape is acceptable. It's not like you're going to find people who say "Well, you know, I used to believe that rape was morally wrong, but hey, now that I know it's a behavior that has been selected in favor of among many primate species, now it's OK--in fact, I think I'm going to exercise my evolutionary heritage by raping someone on the subway this afternoon"--and any person who would do such a thing is clearly not a good person to begin with.

"Furthermore, a lot of evolutionary biology, when studying humans, often reflects the sexism of our society (for example, how common it is to assert that women want monogamy while men want nonmonogamy in evolutionary biology)."

Very common, at least among laypeople. Among serious evolutionary biologists, that idea has been shown not to hold up very well; modern evolutionary biologists have discarded that model in favor of one in which many primate species, including our own, benefit the most by pair-bonding and then cheating. (This idea is supported by sociological surveys, which reveal things like the fact that about 5% of all families in the US have at least one child who is the product of an illicit affair, and the fact that women are statistically more likely to cheat during times when they are most fertile). That's one of the nice things about the scientific method; science tends to be self-correcting over the long term.
james_the_evil1
Sep. 8th, 2007 11:37 pm (UTC)
I hate when people assume that an evolved trait is necessarily the ideal one.

Well yeah, especially when you consider things like Tay-Sachs & Sickle Cell Anemia are evolved survival traits.
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