The Evolution of Buttfaces Explained

While I was very very pregnant about two years ago, I posted something on this blog and then took it down the same day.

It was a labor of love and admiration for BAHfest. I didn't believe it was worthy of submission to the judges, but I thought it was worth sharing here.

But then, even given all the silliness I've posted here over seven years of mermaid-hood, seeing my b.a.h. in print was too much for me to bear and bare. Hence the embarrassment and why I took it down.

Butt now, I have good reason to post it again and for good!

It's all thanks to this news about a recent primatological study:

"Chimpanzees recognize rear ends like people recognize faces"

Here's the rub:

Because rear ends serve a big purpose in the chimp world. Female chimps’ buttocks grow redder and swollen when they are ovulating, signaling to males that it’s business time. And it’s important to know whose bottom it is, in part to prevent inbreeding. The buttocks have, in scientific parlance, a “high socio-sexual signaling function.” 

But when we began walking upright, our bottoms became fleshier and no longer broadcast our ovulation status, possibly to discourage casual hookups in favor of pairing up and sticking together for the children’s sake. On the other hand, humans — “especially females,” the researchers write — developed ruddier and thicker lips, as well as fattier faces.

So not only are chimpanzees better at recognizing butts and worse at recognizing faces than we are, which is interesting in its own right. But this suggests that our faces function like our ancestors' butts! 

Bummer? Yes and no.  On the one hand, this makes my "bad ad hoc hypothesis," re-posted below, worthy of sharing without any more embarrassment. Butt on the other hand, it means it's no longer bad enough to make BAHfest. So, instead of working on this one some more, I need to come up with an entirely new one from scratch if I'm going to have a shot at ever participating.

Butt before I go back to the drawing board (with my hot glue gun, see below), here's that old post. Like that recent news story, it's about butts driving the evolution of primate faces. In this case we're focusing on rainbow-colored monkey butts, but the theories may be liberally applied to this idea that human faces are functionally ancestral hominin butts. OK! Enjoy?

*** 

 “No other member in the whole class of mammals is coloured in so extraordinary a manner as the adult male mandrill.”  ~  Charles Darwin, The Descent of Man, 1874

Darwin was famously astonished by the extraordinary coloration of the mandrill monkey, Mandrillus sphinx. Because males are more striking than females, evolutionary explanations have focused on the adult male. And, as the thinking goes, it's the adult male face that's been the primary focus of selection, with duller female faces and the colorful rumps of both sexes being secondary, in evolutionary terms. 

One explanation for the colorful male mandrill face is sexual selection. Males with healthy, robust physiologies capable of building and maintaining that rainbow visage are the sexiest. And because coloration isn't as pronounced in females, that's an indication that it's less crucial for their reproductive success. But their ability to choose male mates based on good looks is, and the particular genetic mechanism which beautifies the male carries some of that beauty along in females. So that sufficiently, albeit vaguely, explains the mandrill face.

But for many of us an even more urgent question is, Why did the mandrill rump evolve to resemble the face? 

And there are a few possible answers.

There's the more-is-better explanation: those with colorful faces are seen, socially and sexually, as all right, but those with colorful faces and butts are all that. They're the real peacocks of the troop. 

There's also a potential social benefit to being visible and, better yet, identifiable, both coming and going in the dark dense forests where mandrills live. 

Then there's a strength-in-numbers sort of idea, where other groups or predators, even, will see twice as many of you. 

Alternatively, the development of rump color could be genetically linked to face color, so it could simply be an accidental byproduct of selection on the face. 

But what if we flip our view around and assume that the monkeys' rainbow hinies are the primary focus of selection? After all, we find colorful bums and privates across the primates, and in both males and females, and in species without much to match on the face. (Yet.)  This alternative perspective could free us to arrive at the real explanation for mandrill coloration. 

And this means we should ask, Why did the mandrill face evolve to resemble the rump?

Dear Reader, I'm sure you can think up all sorts of advantages to having a face that looks like a butt. 

For instance, by appearing to groom your ass, rather than eat food, you might not attract competitors to your precious food source.

And there's always the Handicap Principle:  He’s got a face like a butt, but he’s still got it going on. And if males are choosy (it's possible!) it could go the other way too.  

It's possible that having basically two rear-ends causes confusion, on the part of the male, during copulation, that can accidentally lead to some innovative, pleasurable positions that strengthen social bonds.

Relatedly, having a face like a bum could be a nice way for females to test male intelligence and choose procreative partners accordingly: If he can't distinguish which end is the business end, then no way am I making this transaction. 

There's great possibility that this coloration is a sort of menage-a-trompe-de-l'oeil. Females are more attractive if they're not one but two! And to any onlookers, this threesome is quite impressive. 

It could be as simple as mandrills getting along better with mandrills with faces that look like butts because that's just, pure and simple, the very best part of a mandrill, to a mandrill. This applies beyond the sexual and into the general social realm.

One, some, or all of the above hypotheses, and many others that I'm sure you've already thought of, could easily explain mandrill face coloration. But I now offer what I think is the best rump-first-then-face explanation of them all. 

When it comes to infants, selection pressures are on hyper-drive, so our adaptive hypotheses about babies are essentially iron-clad. Nature’s got to get infancy right for evolution to continue and nature’s got a genius way to get it right in mandrills and it’s why mandrills are colored the way they are.  

Mandrill face coloration is an adaptation to infant perception.

As mandrill neonates slowly emerge from their mothers’ bodies during parturition, they are gobsmacked by the electric coloration of her rump.

Photo of mandrill birth was unavailable.

Sure, female mandrill rump coloration is not as striking as males', but imagine if it's the first real color you ever saw... ever. So, from a neonate's perspective, this welcome to the world is probably as striking as the healthiest mandrill males' tookus is to other mandrill adults, and to us.

Look closely and you'll see the same color pattern of the male rump is there, just muted.
(captured from Arkive film)

Think about how much we as primates love colors. If you saw that booty upon your earthly arrival, you'd be enchanted. You'd want to keep looking at it, wouldn't you? 

And if it weren’t for the mother’s colorful face proximal to her teats, mandrill infants would be dangerously inclined to literally hang around at the gorgeous yet abysmal end of their only source of food and social development. Food and social boding are, of course, requirements for primate life. 

The colorful bum, alone, is just too distracting. So, mothers with colorful faces to match their butts have more success nursing their infants, and thus have more surviving offspring, that go on to have surviving offspring, than others. They can even get away with those plain whitish nipples because their faces are so enticing.

(source for pic on left)

So that explains mandrill female faces but what about the male rumps and faces? Especially since they’re even more colorful?

This crucial and intense early experience, which selects for colorful mother’s faces, affects mandrill phenotypic preference throughout their lives. 

All social and sexual realms are better with color because of the experiences of these individuals born  to colorful bums and raised by moms with colorful faces.  Colorful males are adaptive in this situation because youngsters fall in love with how they look too, ingratiating themselves with what could be a killing machine, softening his heart and preventing him from ending lineages of mothers with colorful faces who birth babies through their colorful places. 

And this could explain, in turn, why male faces look so much like male genitalia but also why male faces look so much like female genitalia, especially at their peak attractiveness.  (See photo of fertile female's rump, above.) Males with these features are attractive to other males, which promotes group cohesion and reduces tension and competition. Likewise males with these features are attractive to females because it makes them more like their mothers and sisters, that is, not just beautiful but less threatening. 

So that first splash of color that neonatal mandrills experienced is such a technicolor Oz, that they grow up preferring not just color but the most electric adults out there… Runaway selection at its finest! 

To test whether the rump or the face is the driving phenotype…

Dye the butt fur of all the mandrills to match the rest of their olive-colored bodies. All future mandrill babies will be born to a mother's dull rump. And then if selection is relaxed on the face coloration, as predicted by the rump-first approach, mutations should take over and remove the color from the face. Then next, stop dying the butt fur of the mandrills and selection should bring back the colorful face again. Unfortunately this will only answer the question as to which end, the face or the bum, is driving the appearance of the other. 

To test the Perinatal Imprinting hypothesis….

Dye the butt fur of pregnant drills (the rainbow-free cousins of mandrills) to match female mandrills' and see if (a) drill neonates spend too much time hanging around mom’s distractingly colorful butt and, thus, not enough time nursing and bonding with mother’s eyes and face, (b) mother drill's faces evolve coloration in future generations and, also, coloration evolves in drill males too. Easy.

Drill. Mandrillus leucophaeus (source)

But remember, one of the most compelling aspects of the Perinatal Imprinting hypothesis is that it cannot be proven wrong, even if other explanations are better supported. 

Concluding Remarks

Not only is adaptive coloration of the mandrill face secondary to the primary adaptive value of the coloration of the butt, but the adaptive coloration of the males is actually secondary to the primary adaptive value of the coloration in the females!  

Colorful female rumps, and the infants who love them, are responsible for the extraordinary coloration of mandrills, not competitions for sexiest male. Everyone, especially Darwin, was thinking about this all wrong!

 ***

P.S.

I recently donated to Arkive because I heavily rely on it for teaching, writing, and learning. I hope that if you use it like I do, that you'll do the same so that it continues to thrive as a resource. 

My infantile hypothesis  follows in the tradition of the wonderfully infantile ones to be born at Bahfest exemplified by this one from organizer Zach Weinersmith and also last year's winning hypothesis from Tomer Ullman. (2016 note: Dates are off because this note was written in 2014)

Many more words are extinct than those we get to read

I'm starting a new human evolution book project. Technically I've already started it but I've got the greenlight from my agent so it's for real. 

So much writing, at least for me, is just exploratory, organizational vomit that I never times infinity wish to see on the printed page. 

But, here, let me show you my vomit from this morning:

High heels are sexy because they change a woman’s posture so that her boobs and butt stick out and that’s attractive because boobs and butts and because waist hip ratio. 

Wait, no, they’re sexy because they make a person taller and taller is universally attractive. 

What if they’re a handicap or a fitness indicator like a risky bird call or a peacock’s tail? The hampered, painful locomotion signals to potential mates how badass the high heel wearer is. “We will have badass kids!” say high heels. 

source

Or they keep women from being able to escape too quickly if ambushed by aroused men, but that’s too macabre for me to consider further and pisses me off. 

How about, they’re sexy because we decided they are. Culture is weird and powerful: neck lengthening rings, circumcision, Taco Bell. 

Or they’re sexy because they make a woman’s feet look small for her height and this is sexy because … Fibonacci? (Must do calculations.) I don’t know. "Hold me closer tiny footed," isn’t how the song goes. 

But, wait, high heels change a woman’s locomotion. Women who walk in them have an exaggerated female-stereotyped gait. Ask those biomechanists who said so. That’s why heels are sexy, then, they heighten femininity and project its signal further out across the savannah, and into the gaze of more men for longer in each of their numerous salivating minds. 

But why are swinging hips sexy? Because they’re opposite of a man’s? 

But there’s something else that heels do to gait. They make a person unstable, careful, as if they're just learning to walk. One slips into those torture slippers and they're suddenly precious, adorable, in need of rapt attention. Like a toddler, walking for the very first time. 

The idea’s out there, somewhere, that heels make a woman helpless and that’s attractive to men who want to rescue women. This toddler idea is just a fraction of a degree away from that one. Is male attraction to helpless women the same thing that drives them to be doting fathers? Gawd. If that’s true, that means I shouldn’t be as annoyed when they want to rescue full grown women, and when full grown women want to be rescued, because, after all, it’s just good fatherly mojo. But, we’re not babies, dammit. 

High heels. Sexy for so many reasons, but also because they make women into babies and, hey, wait a second...

We don’t think babies are sexy. What the bleep am I talking about? Back up: what we prefer in babies can be preferred in adults for fundamentally similar reasons but those preferences can result in different outcomes. 

Attractive helpless babies get cared for and not sexualized (too much) and attractive helpless women do too but that affection includes bleeping. 

It all makes perfect sense. How on earth did our lineage survive this long without high heels?

Just-So Babies

If you've ever watched a baby eat solid foods, that's DuckFace.

If you've ever seen a shirtless baby, that's DadBod.

Why are we so into these things, whatever they are, right now?

Because whether we realize it or not, they're babylike, which means they're adorable. And all things #adorbs are so #totes #squee right now for the millions (billions?) of social media users in our species. And if they're babylike, they're especially adorable to women and women are more frequently duckfaces than men. And women are increasingly open to embracing, maritally, the non-chiseled men of the world...who knew?

Well, anyone and everyone who's spent a damn second raising a baby, that's who. Especially those with mom genes.

Understanding babies, how they develop, and our connections to them while they do so is key to explaining just about everything, and perhaps literally eh-vuh-ray-thing, about humanity. How can I be so sure? Well aren't you?

We all know that the most attractive women are the ones that look like babies. 

source

And to help Nature out, makeup, lasers, and plastic surgery neotenize us temporarily or permanently, making our skin smooth, our eyes big, our lips pouty, our cheeks pinchable and rosy, and our noses button-y.

That stuff about beauty is common knowledge isn't it? We do these things to ourselves because of our evolved preferences for babies. We find them to be so extremely cute that this adaptive bias for babies affects much of the rest of our lives. Beauty is just the tip of the iceberg because, like I said, babies explain everything: DuckFace, DadBod, ...

And, yes, I do have more examples up my sleeve.

All that weight we gain while pregnant? You think it's to stockpile fat for growing a superhuge, supercharged baby brain both before and then after it barely escapes our bipedal pelvis?

Me and Abe, with hardly an inkling that there's still a whopping five more weeks ahead of us... suckers.

Or maybe I gained 20 pounds above and beyond the actual weight of the pregnancy so that I could protect my baby from calorie lulls from disease or food shortage, especially when those things happened more frequently to my ancestors.

Nope. And nope.

Pregnant women gain all that weight so that its lightning fast loss while lactating leaves behind a nice saggy suit of skin for the baby to grab and hold onto--not just on our bellies, but our arms and legs too. Our ancestors were dependent on this adaptation for quite a while, but over time mothers and infants became less dependent on it when they started crafting and wearing slings. Slings reduced selection on a baby's ability to grasp, you know.

Before slings, selection would have been pretty intent on favoring baby-carrying traits in both mothers and babies. For example, the way that our shoulder joints are oriented laterally, to the side, is unlike all the apes' shoulders which are oriented more cranially, so they're always kind of shrugging. You think we have these nice broad shoulders for swinging alongside us while running, for seriously enhancing our throwing ability, and, of course, for making stone tools? 

No. No. No.

All that's great for later in our lives, but our lateral facing shoulder joints are for being picked up and carried around while we're helpless babies. Our sturdy armpits are necessary for our early survival. And, biomechanically, those shoulder joints are oriented in the optimal way for carrying babies too. It's a win win. Combine that with the shorter hominin forearm, oh, and that itty-bitty thing called hands-free locomotion and it's obvious that we're designed to carry our babies and also to be carried as babies.

Bums come into play here too.

You probably think your big bum's for bipedal endurance running don't you? Or you might assume it evolved to give a stone-tipped spear a lot of extra oomph while impaling a wooly rhino hide.

Wrong. And wrong again.

Our big bums develop early in life because, like armpits, they build grab'n'go babies as well as well-designed grown-up baby carriers.

source

Bums plop nicely on a forearm and most certainly give babies and moms an advantage at staying together. Bums on moms (if not completely liquefied and fed to baby) steady her while holding such a load and also provide something for a baby slung on her back to sit on. Once babies lost the ability to grasp onto moms, babies' bodies had to adapt to be portable objects and moms bodies had to adapt to never drop those portable objects (at least not too far). No doubt big bums, like sturdy armpits, evolved before slings and home bases were ubiquitous in our species. 

Here's another one: The pregnancy "mask."

All those pigmentation changes that we describe as a side effect of the hormones are much more than that. Those new brown and red blotches that grow on a mother's chest and face, those are functional. They're fascinators. A mother's body makes itself more interesting and loveable for the busy, brainy baby on its way. Once we started decorating our bodies with brown and red ochre and pierced shell, bones and teeth, selection on these biological traits was relaxed. But they still persist. Why not? A human baby can't be over-fascinated, can it?

Oh, and fire. That was the best thing that ever happened to babies which means it was the best thing that ever happened to everyone living with babies. Quiet, serene, fascination, those flames... which also happen to process food for toothless babies whose exhausted, stay-at-foraging parents, would much rather swallow the food they chew up for themselves.

The baby also grows fascinators of its own. The big long hallux. Yep. Our big toe is long compared to other apes'. This is where you say it's an adaptation for bipedalism but you'd be only half right.

© naturepl.com / Ingo Arndt / WWF

The length makes it easier to reach with our mouths, as babies. And we teethe on that big toe. Imagine a world with no Sophies! That's what our ancestors had to deal with. Toes as teething toys doesn't seem so ridiculous when you remember that our long thumbs evolved for sucking.

Anyway, this long hallux was a bit unwieldy so thanks to a lucky mutation we stuck it to the rest of the foot and this turned out to work rather well for bipedalism.

Now that it's been a few minutes into this post, you must be sitting there at your computer thinking about boobs.

Yep, babies explain those too! The aesthetic preference for large breasts, by both males and females, is just nostalgia and allometry. You know how when you go back to visit your old kindergarten it looks so tiny compared to your memory? While you're a small human, you spend quite a lot of time with breasts, focused intently on them. But grow your early impression of breasts up in proportion to your adult body's sense of the world and, well, that's quite a big silicon kindergarten!

Your desires, your preferences, your tastes, your anatomy now, your anatomy when you were a baby... everything is babies, babies, babies. Even bipedalism itself.

Gestating a large fetus would not be possible if we were not bipedal. Think about it. All apes are bipedal to a significant degree. What pressured us into being habitual bipeds? Growing big fat, big-brained babies, that's what. Can you imagine a chimpanzee growing a human-sized fetus inside it and still knuckle-walking? I doubt the body could handle that. The spine alone! If you walk upright and let your pelvis help to carry that big fetus, you're golden. Obviously it worked for us.

I could go on forever! But I'll just give you one more example today. It's one you didn't see coming.

Women live longer than men, on average, and a large portion of that higher male mortality rate (at older ages) is due to trouble with the circulatory system. Well, it's obvious why. I'm looking at my arms right now and, complementing these brown and red fascinators, another part of my new mom suit is this web of ropy blue veins. Is this because my baby's sucked up all my subcutaneous fat from under my saggy skin, or... Or! Is it because my plumbing's stretched after housing and pumping about 50% more blood than normal by the third trimester. If my pipes are now, indeed, relatively larger for my blood volume and my body size then, all things being equal, that should reduce my risk of clogging and other troubles. Most women experience a term pregnancy during their lives. I'm sure this explains most if not all of the differences in mortality between men and women.

Like I said, that's just the start. And although I haven't provided evidence for many of the things I wrote, that shouldn't matter. These are just-so stories and they're terribly fun to think about. They're nothing close to approximating anything as lovely as Kipling's but they're what we humans do. If you're not a fan of today's post, hey, it's not like it passed peer review!

Why do cholla cacti use torture?

Ken and I were in Arizona and thereabouts last week visiting friends.  It was lovely -- warm, sunny, lots of good food and good conversation.  We saw some excellent shows -- the Charles Harbutt exhibit at the Center for Creative Photography in Tucson, the Chihuly exhibit at the Desert Botanic Gardens in Phoenix, Penn and Teller in Las Vegas.

Chihuly glass sculpture, Desert Botanic Gardens, Phoenix

And we had some fine desert hikes.

The variety of cacti is astonishing, at least to a north easterner.  So many ways to live in the same harsh environment.

Now, everyone warned us not to touch the cholla cactus.  Or the jumping cholla cactus, or the teddybear cholla cactus, all close relatives.  They all have sharp spines, and whole arms of the plant seem to want to leap off the plant and embed themselves in your skin if you get too close.  Is it too much of a stretch to say it's almost as if the plant were striving to do so, like yesterday's bean plants?

Do not touch!

The arms do fall off easily and around the base of many cholla cacti you can see where pieces have fallen, taken root and started a new plant.

So, at the foot of the Superstition Moutains outside of Phoenix I was walking along, minding my own business when I lightly brushed up against one of these guys without even realizing it, and suddenly I had a 6 inch piece of cactus biting into the skin just above my elbow.  I only wish I'd had the presence of mind to take a picture, never mind video the whole experience like this guy did.



But I didn't because it hurt and I just wanted it -- them -- out.  It hurt particularly because each spine has tiny barbs all along the shaft that make coming back out really hard.

Wikipedia

I'll spare you the details and just say that, happily, unlike in the video, the piece that attacked me had a stem that we could hold onto and pull.  But you have to really pull.  We have since learned that we should take a comb into the desert -- apparently it's easier to disentangle yourself from one of these things using a comb.  Next time.

But it did make us think.  Why would a plant do this?  This brings us to one of our common topics to write about: the problem of the adaptationist assumption, that everything in nature has to be here because of natural selection and that we can infer the reason for that selection.  At least the second part often seems to be assumed when 'the' explanation is offered.

Here conventional wisdom would probably say the thorns are a defense mechanism.  Once poked, twice shy: animals would shun the cholla like the plague.  But why would plants 'want' to be left alone?  Plants, including cacti, can afford to lose a lot of themselves and still survive.  Why spend energy on growing all these spines?  And many plants build in attractors, not repellers -- flowers, aromas, colors, even hallucinogens or flavors. Being eaten, shaken, browsed, and so on is great for them and their potential to bear offspring.  So maybe that's not the answer.

A second explanation also seems obvious:  so many desert plants have spines that they must have something to do with water retention.  Otherwise, if they're just for defense, why aren't all temperate or tropic forest plants spiny?  The preponderance of spininess in the desert almost shouts 'succulence!' at you.  And maybe there aren't even as many animals browsing around in the desert as in rainier forests.

Or maybe it's a self-dispersal mechanism -- stick to a bear or wooly mammoth's coat and fall where you may.  Cholla blobs that land on the ground take root.   But this doesn't ring automatically true because  the mechanism is such over-kill that it's hard to imagine how these spiney blobs could fall out on their own.  So pity the poor javelina who gets one of these in its nose, and then tries to paw it out.  Near certain death -- though nice fertilizer for the plant.  Maybe it was planning ahead.  And if dispersal is the selected trick, why are most desert plants so short-spined?  Are those ones just for protection against animals?

The problem is that there may be no single reason, nor even any single kind of history involved here.  Maybe all these, and perhaps many other, reasons are or were true in the evolutionary past.  Botanists must have many clearer ideas about this than we do, of course.  But we think this illustrates why, even when the assumption that the trait is 'adaptive'--that is, is here ultimately because of natural selection--that assumption is hard to prove and in particular the reason is hard to be sure about.

Story required.

It might seem like it this week, but sex isn't the only recurring theme here on the MT. From various angles, we hit on the culture of science quite regularly, quite relentlessly, and quite hard. We can't help it, we think anthropologically. We want to know the truth of things as much as anyone else, and we think discussing and revealing what we don't know and what obstacles we face are important steps in the process toward knowing. 

One of the ways that science is so clearly cultural is its love of stories. 

I even did the story thing just then. I made science into an actor. 

Try again:  Science is done by humans and humans love stories. 

source

Hardly anybody I know'd deny that.

But what we scientists (particularly evolutionary scientists) seem to resist like the dickens is that we require stories and we are required to fit our work into others' or to write new ones. 

These superstitions can't be the straightest path toward the Truth, can they?

Back up a sec. First, I'm not trying to dump on the power of analogy. Without analogy we couldn't have gotten this far, scientifically. Lacking analogous thinking is a big reason why chimps don't reason. 

And, second, I'm not trying to dump on anthropomorphism or personification because I've done that already recently (and I'd love to talk about something else today).

I'm talking about making our research, our methods, our findings, our results fit our desired narratives. Or any narrative for that matter.

One of these habits we often discuss here at the MT is selectionism which is closely related to adaptationism.

Ken's recent post on this is brilliant: 'Every trait is due to natural selection!'... often said but is it true?

And since reading his piece (and since before) I've been stewing about some related matters, like, why don't negative results get published? 

I'm of the frame of mind to spin the following: Because the story arc where there is no change (no arc?) isn't usually the one that sells the screenplay to Paramount, and likewise, isn't usually the one selling Nature ads and subscriptions.

There's a pretty big recent exception to the negative attitude toward negative results. When they didn't find dark matter, we heard all about it! 

But that's because it was the first exploration of its kind and the spin was that some big time physics equations were wrong and needed to be scratched and reconceptualized. How exciting and productive! And wtf is dark matter?! 

But when people find no significant p-values for any effect of a food or drug on some aspect of health, who cares right? No change. No cause and effect to bring no change about! No results! which is not true, but still... Boring!

In fact, "boring" is what a reviewer called the last paper I tried to publish in a relatively high impact anthropology journal. It was because I didn't push one hypothesis over the others and instead discussed how unfalsifiable and untestable some present anthropological explanations are. The hypothesis I was expected to push--and it was punishably confusing why I didn't--was the story I'd written not too long ago.  Well, because I had already rewritten this entire manuscript since initially submitting it and because I don't think I could have gotten it through a second round of revisions without insincerely and unscientifically pushing one idea over others (which aren't even falsifiable to my mind), I withdrew the paper and will try somewhere else. All I had to do was convince the reader to join me in favoring at least one clever story and I dropped the ball entirely. I flopped because I didn't even try. The story, I thought, was that there might not be a story! If Charlie Kaufman had co-signed my paper, maybe it'd have had a chance? It might have no chance in anthropology journals, but I haven't given up yet. 

Try to find, let alone publish, an evolutionary paper without a story, without circumscribed causes and real or apparent effects. I haven't tried that hard, but I haven't succeeded yet either. It's probably much more common for people to attempt to publish stories but to have those rejected as the wrong stories, the ones not preferred by reviewers, or pushed by reviewers with vested interest in the 'correct' stories. 

Even my little flipbook classroom exercise, which simulates genetic drift, got rejected for publication partly because they feared it would tell the wrong story: intelligent design.

What's hard to swallow is, we can't really know the real natural history in all its glory, and so there's really nothing preventing us from writing natural history the way we want to (within bounds, whatever those may be). And so why's that enough for so many scientists? Why does that suffice? Maybe doing natural history is more like doing history than I ever thought. You get the details correct and you can write the story, the agents, the causes and effects based on your own interpretation and arrangement of those details. And as long as people like your story, you're good, you might even be golden. 

O! What if I'm just an anal retentive weirdo taking it all too literally? 

I didn't bait you here to read me whine and gasp existentially. I actually had more interesting thoughts about the bigger picture to share today. 

For instance, when you see so many potentially real but unfalsifiable evolutionary hypotheses as the stories that they are, it makes it so awkward to watch when science-minded folks spew venom at the "ignorant fantasy stories" of creationists.  

For more in this vein, or related to it, even remotely, I leave you this afternoon with some recent stories about stories, some favorites, others just plain interesting or relevant:

There's no Santa Claus, There's no Easter Bunny and there's no Queen of England! by Joel Adamson
~ If you want to know why I love this piece, see the comments.

Are hobbits human? Textual and genetic analysis of our closest real and magical relatives by Matthew Yglesias
~This is great, but took flak from both sides: scientists for the paleo and nerds for the Tolkien.

...and timely follow-up to that...
Myths matter from Maria Popova 

...and a response to Slate's story about a story...
Slate's embarrassing Middle Earth error by Max Read

Standing up for sex by Henry Gee
From the piece: "Now, I advance the above more than half in jest. It’s possibly no better or worse than any other idea, but I’m not going to pin anyone against a wall and shout about it. "
~ I have a hunch I'll like his book but I'm head-cocking over the attitude given what Nature publishes.

Public's views on human evolution by Pew Research Center

Surprising number of Americans don't believe in evolution by Jaweed Kaleem 
~ I don't believe in evolution either if it always ends in a white dude like the crappy figure they used here.

I had my DNA picture taken, with varying results by Kira Peikoff

Does reading actually change the brain? by Carol Clark-Emory

Claims of 'virgin births' in U.S. highlight pitfalls of self-reported data by Sharon Begley

In saving a species you might accidentally doom it by Ed Yong
~ Knowing the story of natural selection saved these birds from the humans who started out by ignoring it.

We need to talk about TED by Benjamin Bratton
From the piece, "If we really want transformation, we have to slog through the hard stuff (history, economics, philosophy, art, ambiguities, contradictions). Bracketing it off to the side to focus just on technology, or just on innovation, actually prevents transformation." 
~ So many parallels with what admins and students expect of profs.

And finally...

Editing your life's stories can create happier endings by Lulu Miller
~ THIS IS WONDERFUL.

The evolution of peculiar human traits. Sigh

In one short window of Twitter feed on a Sunday morning, people are tweeting and retweeting links to a  a story in the Guardian called "Why do humans cry?", a blog post called "Why do I sigh?".  And, on our ride back to Pennsylvania from Tennessee after the physical anthropology meetings on Saturday, the BBC played a piece on why humans kiss.  The question of why we do X usually has two meanings -- what biological function does X serve, and why did it evolve, though, surprisingly, only the first question is addressed re. the sigh (but we can fix that).  And 'why' always means the natural selection explanation, as is routinely assumed to be necessary and appropriate.

Why do humans cry?  Darwin couldn't think of a biological purpose, but scientists today can, writes Mark Honigsbaum in the Guardian.

In recent decades, scientists have offered several accounts of how the capacity for tears may have given early hominids an adaptive advantage. These range from the aquatic ape theory, according to which tears were an adaptation to saltwater living, to the notion that by blurring our vision tears may serve as a "white flag" to potential aggressors – a signal that the crier is incapable of harm. Then there are the straightforward biological theories, such as the claim that tears evolved to keep the eye moist and free of harmful bacteria.

But perhaps the theory enjoying the widest currency at the moment is the notion that tears are a form of social signalling that evolved from mammalian distress calls – a clear visual signal in other words that someone is in pain or danger and needs help.

Now a new book, Why Only Humans Weep, by Ad Vingerhoets, explains that adult humans are the only mature mammals who continue to signal distress, by crying, even if it might also signal their presence to a predator.  He further suggests that the human's relatively large visual cortex evolved to perceive the nuances of emotion we show on our faces.  "In addition, crying is an emotional expression that signals appeasement and supplication in adults – something that he argues would have been advantageous in early human communities as a means of promoting greater mutual trust and social connectedness."  We also cry tears of happiness and joy, and empathy.

Gustav Klimt; The Kiss (Wikimedia Commons)

Why do we kiss?  This is answered by the BBC's "The Why Factor".  The biological reason is that it's pleasurable, and appeals to all five senses.  And it evolved because our primate relatives signal sexual receptivity with bright red, swollen genitalia, but when our ancestors began to walk upright, their sexual receptivity signal switched   to their full, pink lips, which have a 'come hither quality about them'.  This is called "the genital echo" (the reddened genital signal moved upwards, and this also explains why human breasts evolved to be larger than the mammary glands of our non-human primate relatives -- they look like sexually appealing buttocks).  This could be when lipstick evolved as well, but it's hard to say since it doesn't preserve well in the fossil record.



Why do we sigh?  One researcher who addressed this question received the IgNobel Prize for his efforts.  KH Teigen in 2011, though, in fairness (and sounding a touch defensive) he told one blogger he was doing the work to make the point to his students that there were subjects that haven't yet been studied by psychologists.

The answer is that sighing helps your breathing when you're stressed, is an expression of annoyance, and it's a "mental reset button".  How do we know?  Teigen and colleagues at the University of Oslo used a questionnaire to elicit the feelings people associate with sighing, feelings about others sighing vs themselves sighing (we do it when we're frustrated but others when they are sad).  And they gave participants two puzzles, one easy and the other one impossible, and asked people to try to solve them, but to quit whenever they wanted to.  They counted sighs as people worked on the puzzles.  Seventy seven percent of people sighed, most 4 times.

Researchers at the University of Leuven (Vlemincx et al.) also studied sighing, and have just published a new review on the subject.

The causes and consequences of sighing are reviewed and integrated in the proposed model in which sighing is hypothesized to function as a resetter in the regulation of both breathing and emotions, because it restores a balance in respiratory variability fractions and causes relief.

So, researchers have answered the question of what biological function sighing might serve, but we're astonished that they haven't addressed the evolutionary question which would be, essentially, what is it about sighing that caused our early ancestors who sighed best to have more children?  Since no one else seems to have answered this, we may as well.

If it's true that when we see someone sigh, we think that person is sad, then clearly it evolved for much the same reason crying evolved.  (Except that it involves the auditory part of our brain, not the visual, which is a bit of a problem.  Why isn't our auditory cortex more highly evolved?)  So, as we evolved living in small bands, we were empathetic and when someone close to us was sad, we would have wanted to help.  And, well, it's a short path from helping someone feel happier to mating with them -- sometimes it's one and the same act -- so this may well explain the origins of sighing.

Oh, except that cats sigh, dogs sigh, hell, maybe even lizards sigh.  So, we need an explanation that predates our earliest hominin ancestors.  Well, dogs are empathetic, so maybe our explanation still holds water.

Prairie dogs kissing (Wikimedia)

And as for kissing, although it has a magical, neurological, 5-sense etc. evolutionary origin, as explained by the interviewees on The Why Factor, and is therefore also part of our unique Darwinian heritage, well, yes, it's true that it's not universal and has only spread worldwide in more recent times.

Nothing like water tight explanations of everything in Nature!  It seems anybody, journalist or professor (anthropologist or not) is qualified to write books or be interviewed internationally, with essentially nobody questioning either the explanations offered, or the offerer's credentials, or whether anybody has such credentials when it comes to some of these evolutionary 'explanations'.

Sure, it's possible that crying, sighing and bussing were naturally selected.  That is, that those who cried, sighed and kissed best had the most children, and therefore that the traits became fixed in the human population.  But this is something that can't be tested, nor can the reason these traits evolved be ascertained.  But that doesn't stop people from speculating.

And it's possible that these traits have a significant biological function.  But these can't be ascertained with certainty, either.  And, they have to be shown to serve the same purpose cross-culturally, which Darwin certainly tried to do with his speculations about emotions, but which is very difficult.

Speculation is fun, not new, and it pays the bills, so why bother to complain about it, except for the myth that science is about knowledge, and science programs are about education. Supposedly.