As I so often do, I’m going to start this post with something that seems totally un-related to the main post, but which I will manage to tie in- in a surprisingly relevant way- later on. And the thing I’m going to start off with is… my kids’ piano lessons.
No, no- wait! Don’t click away! I haven’t lost it, and I assure you WTWWU isn’t turning into a mommy blog. This will be relevant.
So we have a piano in the house. Awesome Wife occasionally pulls out some old sheet music and plays for a bit. A couple of years ago, we noticed that Twin B would often sit down at the piano and start improvising. And the thing was, her improvising- just pure making stuff up- sounded really pretty. Check out this video from 2 years ago.
After hearing her do this a couple of times, AW and I said to each other, “Hey, she seems to like playing the piano. Maybe we should give her lessons?” And so we signed up not just Twin B, but the whole Trifecta.
Our expectations were that Twin B would shine, Bird Whisperer would do OK*, and Twin A would struggle a bit. Twin A was the slowest of the 3 to catch on to reading, the slowest to start talking, and in several other ways has matured a bit more slowly than the other 2.
*Bird Whisperer is smart enough to do most anything well, but he deals with piano as he does with most matters outside the lens-like focus of his interests: the absolute minimum to get us off his back.
So how’d it turn out? Exactly the opposite. Twin A took to piano- and musical notation- like a fish to water. Twin B on the other hand, our little girl-genius who practically learned to read when we weren’t looking- has struggled, nearly unable to read basic notes after a year+ of instruction, to the point where we’re considering changing teachers and/or teaching methods.
Musical talent. Hold that thought.
Now let’s talk about me and my latest self-improvement project. Guess what I’m doing? Taking a night class? Learning a foreign language? Taking up yoga? Learning judo? No, no, hell no, and no. I’m growing a beard.
Tangent: Before I go any further, I want to give some advice to any male readers considering growing a beard. It’s critically important that you position your beard-growing as something you are proactively doing, and not just something you are allowing to happen to you. You’re not sloppy or lazy or unhygienic; you’re ambitious, you’re a go-getter, you’re always taking on new challenges, and growing a beard is just the latest exciting challenge you’re taking on.
Here’s an example. Let’s say a friend you haven’t spoken with in some time emails you and asks what you’re up to. You could reply with something like: “Things are super-busy, but great! Work is crazy, the kids have started school again, and on top of all that, I’m growing a beard!...” Or if your spouse asks you something like: “Are you going to have time to put up those shelves in the garage this weekend?”, you could say: “Probably not. I’ve got a pretty full plate this weekend, what with everything going on and working on my beard and all…”
I’m growing a beard for several reasons, including, but not limited to:
2- I’m bored with my face. No I don’t hate it; I’m not getting a nose job or anything. I’ve just been looking at it for a long time in the mirror, and I want a little break, both from seeing the same face, as well as from staring at it so darn long while I shave every day.
Tangent: I’m a white guy with dark hair, which means that when I do shave, it needs to be a close shave, or I look like a mobster or President Nixon. Electric razors have never worked for me, nor for that matter, has shaving without a mirror. Lots of guys talk about how they shave in the shower, and then I see guys actually shaving (with electric razors) while they drive! How do they do it? I can barely drive in a straight line with both hands on the wheel, and here are these guys shaving at 75MPH! Why just the other day I tried to change the radio station while driving, and I swerved so badly I had to stop texting, spilled my latte and nearly dropped my Egg McMuffin on the newspaper I was reading! OK, not really.
3- The Trifecta egged me on.
Tangent: And they are being, I must say, wildly supportive of this project. They check the beard daily, touch it, offer compliments and encouragement. This is, sadly, in stark contrast to the feedback from Awesome Wife, who I have to report is staunchly anti-facial hair. In particular, she claims that my new beard makes gives me an uncanny resemblance to a certain Mideast political leader.
Me, I don’t see it.
4- I was worried that if I waited too many more years it would come in gray, and then I’d look like the snowman-narrator in the Rudolph special. (Of course I’d still wear pants.)
5- Finally- a real reason: Beards are great for outdoor sports in Winter. Yes, I’ve grown beards before, and this is absolutely true. When temps dip below 30F, a beard is wonderful when running or biking. And for skiing, they’re fantastic, particularly on a stormy day when they ice up, creating an insulating mask over your lower face. In contrast, they’re not so fun on a hot summer day, and that’s why I’m growing it now.
And really reason #5 brings us to the point of the post (and yes there is one and I am getting to it) which is why? Why do men grow beards? And it seems pretty obvious, right? Because it’s warm. Because back in caveman times things were cold, what with the Ice Age and all, and a nice warm beard would help keep your face from getting frostbitten, help retain head in your head and reduce the whole risk of death from hypothermia thing. Makes sense, right?
Except that if you stop and think about it, that makes absolutely no sense at all. First, why would only men have beards? Don’t women’s faces get cold? And what about children? And not all men even grow beards. While they’re common among European men, lots of people around the world grow hardly any beard- just a few whisps of hair on the chin. Know who doesn’t grow beards? The Inuit (pic left, not mine). That’s right, Eskimos grow only little whispy beards- talk about people who need to stay warm!
Side Note: Inuit by the way are a great example of people with real cold-adaptations. The distinctive epicanthic fold (pic right not mine- think it’s from NY Times) of the eyelid is commonly cited as an example (to protect the eye against cold, wind, sands, glare) though it’s not quite clear how much protection it really affords. But non-shivering metabolism of Inuits is something like 30-40% greater than in control groups, and recent research suggests that even the hands of Inuits may have an enhanced, heat-retaining morphology.
Well, maybe then it’s just a hold-over from when our ancestors were hairy all over, and somehow some portion of human males just never full lost the fur coat on their face? The problem with that idea is that our closest relatives- chimpanzees and gorillas- don’t have beards. Sure, they have hairy faces, but nothing like Santa Claus-length beards we can grow.
All About Sexual Selection
So what’s the deal with beards? The answer is, apparently sexual- as opposed to natural- selection. Natural selection is the process that drives the obvious features of evolution- why a cougar has big teeth or why a pronghorn is fast. Because the mealy-mouthed cougars and slow pronghorns didn’t survive well or long enough to reproduce as effectively. Sexual selection is the process that drives evolution specifically through an organism’s ability to attract and procure mates. So let’s go back to Porcupines: if a male Porcupine is strong and healthy and has a great coat of quills and everything else needed to survive, but he’s incapable of performing the trademark “urine-shower” to court a female, he won’t leave any descendants behind. So male porcupines are selected for- among other things- their ability to perform effective urine-showers, and that type of selection is called sexual selection. There’s no individual survival benefit to being able to explosively urinate all over a female porcupine, but because female porcupines find urine-showers arousing, sexual selection for urine-shower-ability shapes Porcupine evolution.
Sexual selection has been used to explain all sorts of animal characteristics that don’t seem to have any traditional survival benefit. A peacock’s tale, a lion’s mane and a Lazuli Bunting’s plumage are all thought to be the result of sexual selection processes. Sexual selection is also suspected to be the driver behind the evolution of human male and female body shape, armpit & pubic hair, human female breasts, the human penis* and yes, beards.
*I’m trying to keep this post PG13, but here’s the deal: there is no biological reason for the human penis to be anywhere near as large as it is. The erect penis of a gorilla for example, is about 1.5” in length, and it appears to achieve its reproductive function just fine. Human female breasts are also- biologically speaking- completely unnecessary. There is no correlation between non-lactational breast size and ability to produce milk.
So apparently, at some point in our* past, women found bearded men to be more desirable than un-bearded men, and bearded men produced more offspring, leading to a population in which males are bearded.
*I’m using “our” in a fairly parochial sense here, as in peoples in which the men have beards- like white people, for instance…
Or maybe not. Sexual selection also drives the development of features or traits designed to outcompete rival males for access to females, either through force or intimidation. The muscles of a Gorilla and the antlers of an Elk are two great examples. Both can be used to fend off competitors, and in fact the mere appearance of either is often enough to dissuade prospective suitors. Perhaps a heavy, bushy beard makes a man appear more threatening, more menacing, more virile, more bad-ass, and serves to intimidate prospective rivals.
*Incredibly, this same mechanism- visual intimidation of prospective male rivals- was actually proposed as an explanation for human penis length back in the 1960s!**
**To clarify, I mean that the idea was proposed in the 1960s. I didn’t mean to imply that human penises were longer in the 1960s.
This is the wonderful and the awful thing about sexual selection; it provides plausible explanations for so many biological traits- like the peacock’s tail- that otherwise make no sense at all. But at the same time, sexual selection provides so many possible explanations that it sometimes seems like it can be used to explain away nearly any peculiar trait.
Tangent: So back to my beard- which is it? Attraction or threat? In my current life, the one female whose opinion matters is, as I’ve mentioned previously, anti-beard. But I have grown beards previously, and in fact my first beard, during my junior year in college, I sported during a time when I was both single and in avid* pursuit of female companionship. Here’s what I found:
*OK, “desperate”, really.
Most modern American women (at least at the college I attended) do not go for beards, and I would say that something like 70% of women pretty much immediately rule out men as a dating prospects if they’re bearded. But- and here’s the key thing- having a beard got you off to a better start with the remaining 30% than not having a beard did with the beard-hating 70%. Get it? So while my pool of dating prospects was smaller, I was better-positioned within that smaller pool.
All About Skin Color
It gets even more confusing in that some traits may be shaped by a combination of natural and sexual selection. One example is skin color. For decades*, variation in skin color was thought to be directly-related to solar exposure. People in sunny places had dark skin so that they didn’t die of skin cancer,. Melanin blocks UV. But people in places with very little sun had light skin, allowing them to obtain more UV from the limited sunlight they received. A certain measure of UV is necessary to synthesize vitamin D3, without which a number of developmental problems- including rickets- can occur.
*I believe William F. Loomis was the first to formally propose this idea back in the 1960’s.
But in the 80’s and 90’s, other scientists* questioned this conventional wisdom. While skin cancers are awful and all, they overwhelmingly don’t afflict victims until after prime reproductive years. Yes, very fair people would probably suffer greatly from, and maybe even succumb to, sunburn-induced overheating and even secondary infections from sun-poisoning, but most moderately-complected white-skinned folks- like me for example- would probably sport a deep tan for a few decades before falling to cancer- plenty of time to bear and raise offspring. Instead, perhaps different groups in different parts of the world tended to select for fair or dark skin in different areas because they found those skin shades attractive, just as other facial or body features may be more or less attractive in different societies and cultures around the world.
*The ideas in this paragraph are drawn mainly from Jared Diamond. That’s right, the guy who wrote The Third Chimpanzee, Guns, Germs and Steel, and Collapse- all great reads, BTW.
But in the late 90’s other researchers* studying UV radiation and its effect on folates proposed a 2.0 version of the natural-selection hypothesis for skin color. Loomis, they said, was half-right. Fair-skinned peoples (pic right = white guy) such as Northern Europeans did benefit from greater receptivity to UV for D3 synthesis, but skin cancer was not the principal threat to fair-skinned peoples in sunny climes. Rather it was the damaging effect of UV on folates, or folic acid. Folic acid is necessary to synthesize nucleotides, which are the structural building blocks of DNA and RNA. Without sufficient folic acid, you may suffer from anemia and some other nasty effects. But for a developing fetus, lack of folic acid is catastrophic and can lead to an array of growth deformities including spinal bifida.
*Ideas in this section are those of Nina Jablonksi and George Chaplin.
Interestingly it also turns out that folic acid plays a key role in spermatogenesis, the creation of sperm cells, and so men with insufficient folic acid are often infertile. So it sure seems logical that sunny climes would favor darker skin and less-sunny climes (>latitude 40N or S) would favor lighter skin.
But on the other hand, darker-skinned people do occur in some notably un-sunny places. The Inuit are not a fair-skinned people, and natives of the cloudy New Guinea highlands or cool, Southerly Tasmania* are very dark-skinned.
*Savvy Southern-hemisphere readers may object that perhaps I should be referring to Tasmanians in the past tense, since the last full-blooded Tasmanian (pic right) died well over a century ago. I’ve heard that this is a sensitive issue with present-day mixed-blood Tasmanians, and so have elected to use the present tense.
Well, yes, but Inuit don’t require all that much UV exposure because their heavily fish-based diet provides ample D3. And the Southern hemisphere lacks large land-masses South of latitude 40S comparable to the huge Northern hemisphere land expanses North of latitude 40N, which makes the rise of Southern-hemisphere fair-skinned peoples less likely…
See what I mean? It goes on and on, and it may well be that both explanations- natural and sexual selection are at least partially correct when it comes to skin color.
Tangent: Before leaving skin color, I have to mention 2 absolutely fascinating things about the topic. The first is that white skin appears to have come about twice, independently. Paeloanthropologists generally believe that the first hairless hominids were dark-skinned, due to their African origins.
Nested Tangent*: The earliest hominids were presumably hairy, like Chimpanzees and Gorillas. Hairy primates usually have either lightly or un-pigmented skin beneath their fur. Once hairless, hominid skin would have benefitted from (presumably dark) pigment. The whole issue of human lack of body hair is another huge, controversial topic outside the scope of this post. But the most widely-accepted explanations center around our increased number of sweat glands relative to other primates, and which probably came about as our ancestors took to a bipedal lifestyle.
*Yes Sid, I am getting technical in a tangent and a nested tangent. Get over it.
White skin is thought to have come about later, as humans migrated to areas North of latitude 40. And in fact researchers have identified likely mutations that caused this shift to lighter skin in both Europeans and East Asians. But- and here’s the freaky thing- the mutations are different between the 2 groups, meaning that Europeans and East Asians are “white-skinned” through completely different genetic mechanisms.
The second fascinating thing is blond hair, which does seem to be the result of sexual selection, possibly in just the last several thousand years*. Northern Europeans are of course known for a high incidence of blond hair color, but what’s interesting is that blond or “dirty blond” hair is much more common around the world in children. Australian aboriginal children for example (pic left, not mine) often have blondish hair which darkens as they mature. And even among blond-haired adults, hair color almost always darkens by the late 20s/early 30s*. Blond hair appears to be a youth indicator.
*My source for most of this section was Matt Ridley's wonderful book The Red Queen. It's probably my 2nd-favorite Ridley book, the 1st being Genome.
**News flash for spaceshot-men like me: Nearly every blond woman you see over age 30 is coloring her hair. I am embarrassed to admit I did not know this until I was over 40. I know, I am clueless.
Human males are generally attracted to female physical characteristics that indicate youth and reproductive health, such as figure/body shape and skin tone. In a cold Northern climate where people are heavily clothed much of the time, such indicators may not be generally obvious. But hair color is, and a head of blond hair could reveal a 5 or 10 year age-difference that clothing might otherwise conceal. Men who “selected” such blond/younger women (pic right, so not mine) might end up with a mate who had an additional 5-10 available child-rearing years, leading to more children and… you get the idea.
It makes sense that sexual selection would shape anatomical characteristics related to mate selection, attractiveness and reproduction. What’s really fascinating about sexual selection, though, is all the non-obvious characteristics which it is suspected to drive. Here’s the most fascinating one: the human brain.
About a year ago I posted about the Pronghorn, and how for many years the big mystery about it was why is it so damn fast? Since it’s way faster than any possible predator, what could have driven evolution* to make the animal such a fast runner?
Here’s a similar question about another mammal: Why does the human brain need to be so damn big? Our large brains allow us to do all sorts of fascinating things- visit the moon, build particle super-colliders, compose symphonies and paint masterpieces. But there was no selection pressure to be able to do those things- clearly the need to build spacecraft could not have driven our evolution.
The standard explanation is that the human brain evolved to facilitate better hunting and tool-making. But really, you don’t have to be Einstein to outwit a mammoth or skin a rabbit. Yes, some smarts would help, but do you really need a brain 3 times the size of a Chimpanzee’s? Somehow, something in the last few hundred thousand years drove a dramatic evolution of the human brain, and one possible explanation* is sexual selection.
*The ideas in this section are largely those of Geoffrey Miller as described in his fascinating book, The Mating Mind.
In a social species like us, a smart guy, who can better understand motivations and emotions, is going to be more effective at attracting/ charming/ seducing females than a dull-witted guy. Females who mate with such smarter males will presumably bear smarter children, who will similarly enjoy the enhanced mating opportunities of greater intelligence. Smarter males might well have been able to negotiate and position themselves better within a group, with access to better resources, authority and mating opportunities. Females would have similarly benefited from higher intelligence in negotiating social position and access to resources for themselves and their young. And equally importantly, higher intelligence would benefit females in evaluating potential mates.
Mate selection among mammals (and most animals) is a higher-risk investment for females than males. In Pleistocene times females who made bad mate-choices, in terms of that mate’s health, character, social prospects or access to resources, would have left behind fewer descendants than those who made “good” mate choices. And so the ability to fully evaluate a prospective mate- not just their strength, health and vigor, but also their intelligence and charisma, became even more critical.
Back to Where We Started
According to Miller, many of the expressive and even artistic abilities in modern humans may have arisen as mechanisms for displaying mental acuity, creativity and resourcefulness to prospective mates. Even music. Which leads us back to… Twin A. (Sorry for the poor video. It is, regrettably, the only one I have. Skip the first 30 seconds.)
Neither my beard nor Twin A’s musical talents seem to make a lot of sense from a natural selection standpoint. Neither would help us kill a mammoth, outrun a leopard or survive a bout with malaria. But perhaps sometime in the last 100,000 years our ancestors faired just a bit better on the dating scene because they sported extra whiskers or could carry a tune.
Twin A is continuing piano lessons this Fall, and I’m looking forward to many warm-faced days over the long Winter ahead. Or maybe I’ll just move to Iran and run for office.
One More Thing
This part isn’t essential to the post, but I wanted to get it off my chest. Here’s my biggest beef with Sexual Selection: it’s continually presented as separate and distinct from natural selection, which contributes to a confusing perspective of Darwinian evolution for the layman. It’s like, “Oh hey, natural selection pressures- avoiding predators, not freezing to death, being able to run/fly/bite/whatever- that stuff drives evolution. Except for this other stuff, like feather-plumage and blond hair and boobs. That’s driven by this completely different mechanism…”
This distinction between natural and sexual selection has been made ever since Darwin, and I think it’s artificial and unnecessary. Sexual selection is part of natural selection, or more properly a subset of it. Sexual selection pressures are just one slice of the vast array of selection pressures faced by all living things, and I’d argue for a more holistic view of natural selection that includes sexual selection.
As always, remember I’m a layman with zero scientific education or qualifications, and so I may well be talking completely out of my ass. But I really do believe that a good part of the reason we have millions of intelligent, literate people dismissing evolution as “just a theory” and believing the world is only a few thousand years old is because scientists so often do a crappy job explaining stuff that just about everyone should be able to understand. And anyway, even if you don’t agree with my argument for a more holistic view of natural selection, then at least we should be able to agree about my beard. Doesn’t it look awesome?