Human Nature

There have been a couple of articles lately that have given me pause because of their poor interpretation of human nature. I can be a misanthrope with the best of them, and certainly living in the reactionary-right-wing bastion of Canada, at the end of the Bush years and soon after the G20, does nothing to improve my opinion of human kind. But I'm also a mom to a darling little girl, who's going to have the earth I leave her, so the nature of the dominant species on this planet is an important question to me.

In Scientific American, John Horgan discusses the book Mothers and Others by Sarah Blaffer Hrdy (Our nature is nurture: Are shifts in child-rearing making modern kids mean?). Sarah Blaffer Hrdy is an evolutionary biologist/anthropologist, who really sounds like someone I might like. Dr. Hrdy worked as an anthropologist during the years when women's contributions to science were not readily accepted, and also raised three children. Her book emphasizes a type of child-rearing that allowed her to pursue her career - allocare, or the assistance of non-related members of the troop. Group child rearing differentiates us from the rest of the great apes, who rear their offspring individually.

In his article, John Horgan then goes on to discuss modern human societies. Many of today's children receive most of their care from non-kin, and often times care from the parents is distant, which can result in disorganized attachment. Might this then result in a loss of empathy in our species, if empathy is not selected for? He then cites a recent study showing that empathy in college students has suffered a precipitous decline in the last 30 years.

I'm going to go out on a limb here and suggest that Sarah Blaffer Hrdy probably didn't say this in her book, because no evolutionary biologist would suggest that any phenotype can be selected against in roughly one or two generations. Not only is 30 years much too short a time frame for the evolutionary loss of any phenotype, but it would require that empathy be strongly selected against. Certainly the misanthrope in me thinks this is the case in modern society, but in reality empathy is required for the most basic of human interaction and communication, so its selection against seems unlikely to me. But it isn't the science of this article that upset me. I wasn't really sure, however, what was bothering me.

Then tonight I reread an old issue of Discover and came across an article by one of my favorite columnists, Bruno Maddox. He shares my love of Ghost Hunters and wrote eloquently on one of Darwin's bigger mistakes. In "The Body Shop" (Discover, May 2010, pg 43) he discusses the rise of the robot, and wonders why people aren't as disturbed by robotics as they used to be. A large body of 20th century literature examined the fine line between the potential advantages and dangers of robotics, and until just recently, we all seemed to be terrified of the thought of robots taking over the earth. Now, as robots adopt human-like faces, vacuum our floors, and take over the battlefield, we seem to have quietly given up our fears of being made obsolete. Why? Maddox suggests that this is because we've really stopped thinking we're any good at all. The basis of our fears of robots was our belief in unique nobility of humans. Maybe, however, in the age of the internet, we suddenly realize that humans are largely stupid. "[Man] enjoys porn and photographs of cats on top of things. He spells definitely with an a, for the most part, and the possessive its with an apostrophe. On questions of great import or questions of scant import, he chooses sides based on what, and whom, choosing that particular side makes him feel like, and he argues passionately for his cause, all the more so after facts emerge to prove him a fool, a liar, and a hypocrite." Perhaps then, our fear of robots has been replaced with a hope that they can be programmed to be the intelligent, rational, even empathic beings that we have failed to be.

And there it is. This particularly Judeo-Christian idea of the fallen angel. That mankind's nature is inherently selfish and irrevocably sundered from our noble origins. This philosophy has coloured western philosophy for centuries; Thomas Hobbes' depiction of life as naturally "solitary, poor, nasty, brutish and short," Garret Hardin's Tragedy of the Commons. I can't underestimate how much this philosophy has coloured the thinking of the west, and we hardly seem to question it. But we should question it, strongly. Because in a world where humans are basically jerks it becomes very difficult to put in the energy to make it better. It makes it easier to care less for our neighbours, and easier to accept injustice.

It would be easy to categorize my objection to this poor view of human nature as a womanly or sentimental instinct to protect my child, and to be perfectly honest, that is part of it. No parent wants their child to grow up in a society that is irredeemably selfish. But the bulk of my objection comes from the fact that this cynical view of humanity is just too easy. It's simple to look at the state of the world and roll your eyes. Cynicism takes no courage and leaves no room for outrage.

The cynic in me doesn't have a hard time accepting that college students of today are less empathetic than they were thirty years ago, but the optimist in me doubts strongly that this is due to some genetic decline. Instead it seems clear the problem stems from a culture that strongly rewards self interest and devalues idealism. This is not the real tragedy, however. The real tragedy is that, like a rapacious economy and lying politicians, we think that this is the natural, immutable progression of our society. There is no scientific or anthropological reason to suggest that humans societies are limited by rapacious self interest, so let's not give into a poor philosophical excuse.

Intralocus conflict in evolvability of parenting traits - it's way more catchy than "Men are from Mars, Women are from Venus"

Oh, I mention gender differences in parenting and everyone gets their panties in a bunch. Cries like women. Bangs their chests. Clearly there are a lot of weighty preconceptions that come to the fore when we talk about the differences in parenting between men and women. The difference between men and women is the trite fuel of bad comedy and self help books (he's just not that into you) but it's hard to deny that there are innate differences. Well, what's innate and what's learned is a big question. Nature versus nurture, that old chestnut.

Parental investment varies a lot in the animal world. From fish that lay eggs and swim away, to seahorses in which the male invests a lot of time and care, harem-maintaining mammals, and monogamous birds. Again, from an evolutionary perspective, a lot of it boils down to the only reliable difference between males and females, in plants, animals, and insects (notably not always fungi - there can be hundreds of mating types in fungi, but I digress). Females produce larger gametes - the egg. That's it. Only difference. But from that, so much follows. Males therefore have an easier time producing gametes, hence produce, and spread, more gametes than females. Females invest more from the very start, so automatically have more reason to continue investing in this one egg. From this initial imbalance, there is a selective pressure for males to invest less, and females to invest more. But let's not take this to mean that males have it easy: even in harem maintaining species, males have to invest a great deal in fighting, attracting, and guarding females. Yet it still remains a truism biologically and in human societies: males benefit from spreading their seed far and wide and females benefit from tying them down to take care of their offspring. Bring home the bacon. Thus males are cast as rogues and women as the ball and chain.

CLEARLY this doesn't explain everything, because if life were that simple then the animal kingdom (and Calgary) would be full of harems. I was MOST disappointed, as I did research for this post, that a great model system for investigating parental investment is burying beetles. That's right. Beetles that burrow into a carcass to lay their eggs. Who knew that carrion-eating bottom feeding insects were instructive to everyone, not just Wall Street executives? Intellectually, burying beetles are quite interesting because they're the only non-social insect in which both the males and females invest care in their young. But in reality they're disgusting, their offspring are maggots, and they live in rotting dead animals. And try googling "sex determination in burying beetles" and finding anything to read that does not contain pictures. And if you know me, you know I'm TERRIFIED of bugs. I'm ashamed to admit that I have invited people over (begged?) for the sole purpose of killing a silverfish in the bathroom. Anyway, I did manage to learn, before shuddering, turning off the computer and grabbing a beer, that male and female burying beetles both care for their offspring by regurgitating rotten food and spreading the carcass with anal secretions to keep it fresh enough for the maggots to eat. It's okay, I'll wait. Go get a beer. But here's where it gets interesting. If you take one or the other partner away, the remaining parent is equally capable of performing these tasks and the offspring are fine.

So are the parents in this case completely interchangeable? Truly equally helping each other out in a completely cooperative manner? Evolution would suggest that this wouldn't be a stable situation. And sure enough, the females to tend to specialize in direct care more when both parents are present. So the authors of a particular study (Walling et al. 2008. The quantitative genetics of sex differences in parenting. PNAS, 105:47. Spoiler alert: there are pictures.) investigated whether this situation would be stable. Say if perhaps the situation changed and the species were forced to evolve such that either males or females became the predominant caregiver. This is a new and interesting type of question: basically the authors were curious as to how evolvable these traits were. And surprisingly, male direct care was less evolvable than female direct care. In other words, lack of direct investment by males wasn't just the evolutionarily smarter thing to do, it was the only option available genetically. If selection increased for male direct care, there wasn't a lot that would change in the species, because the gene for direct care in males was incapable of increasing its influence. The reason for this is the title of this post - intralocus conflict. It's complicated, and not that interesting. The take home message is that some solutions aren't necessarily the smartest evolutionary strategy: they might just be the most convenient for your genetics.

As evolutionary biologists we spend a lot of time coming up with explanations for why things are the way they are that credit selection for everything. It's nice to be reminded every now and then that selection doesn't determine everything. Thus no one gets to use "I'm evolutionarily inclined to spread my gametes" as an excuse for infidelity. And the whole question of evolvability adds another layer to the old question of nature vs. nurture. It asks us: just how written in stone is the "nature" portion of ourselves?

You're advertising WHAT??

We’re a young family and I’m a scientist so as you can imagine we are short on nickels to rub together, so I sold out to the man and added ads to this blog (Day one – 37 cents – thank you Mom!). This is a Google-run enterprise so you would think they would be pretty good at matching content, but what do I see when I checked for comments today (Day 21 – one comment – thank you sister!)? AN AD FOR AN ANTI-EVOLUTION BLOG!!! One can only hope that a) I get another 37 cents for clicking on it and b) he/she gets ads for my site.

It would be marvellous to have a civil discussion about evolution and theology. The problem really is lack of common ground, and the kindest way I can put it is that evolution is based on evidence and intelligent design is based on faith at best and wishful delusion at worst. But for meaningful discussion about science, there are two basic popular misconceptions that have to be cleared up. First, a theory in science does NOT mean some wacky idea that hasn’t been proven yet. So when it’s called the ‘Theory of Evolution,’ that is not to imply that it is a neat idea that may have some merit. In this case, theory means a group of principles that guide our understanding of basically all of biology. Secondly, just because there are two explanations does not mean that they have equal validity. So often, the media will give equal time to two explanations of a phenomenon. It gives the impression that there is a credible other side; but as for global warming and vaccine efficacy, the scientific evidence for evolution is overwhelming. I keep thinking of Lewis Black stand-up: “FOSSILS! FOSSILS! FOSSILS! I WIN.”

Creationism as a competing theory fails on the ground that it is not science. In a fascinating decision, Judge John E. Jones III of Pennsylvania ruled that Intelligent Design – the more popular cousin of Creationism – is not science. The case Kitzmiller et al. v. Dover Area School District pitted was a captivating test of this question, as the school district was trying to include Intelligent Design in the science curriculum. Essentially, because Intelligent Design is not a theory based on evidence, it does not qualify as science. You can read the full decision here and an interview with Judge Jones here.

Anyway, that’s my rant. As I watch the ads being renewed I can see there are a lot of blogs devoted to creationism. Kudos Google. I wonder if after my agonizing post about SUVs there will be a Hummer ad next. Let me know.