Walk this way, talk this way, roll in the hay

Teaching anthropology and human evolution involves tearing down stubborn misconceptions and stimulating students to discover and to behold their culturally-limited assumptions objectively.

That's if you're skilled and if you're lucky. OK, let's be honest: that's if you're supernatural.

The job sometimes feels like digging a hole, going deeper and deeper, never having the chance to mold something out of all that dirt, to build upon existing knowledge and insights. To move upward and onward.

Enough preamble though. There's a point today and it's got to do with:

The ever-annoying, but ever-so educationally priceless enigma that is... The Neanderthals [appropriate sound effect... and more].

I just finished a semester of Paleoanthropology where my students were asked to answer, "What happened to the Neanderthals?" for their course-long and final projects.

Even a familiarity with Neanderthals from their Intro to Bioanth or their Intro to Archaeology course does not fully prepare all upper-level Paleoanthropology students to consider them in a more advanced scientific framework. In fact, I think that familiarity combined with the claws of pop culture can inhibit them.

Despite hosting an expert to present to my students the many obstacles and issues with identifying extinction and its causes in the fossil record, and despite an admittedly brief but explicit exposure to the cutting edge genetic evidence, some of them still assumed they were charged to find the cause of Neanderthal extinction.

Two of them went so far as to rewrite my question at the top of their final paper as, "Why did the Neanderthals go extinct?" They had no idea that their version of my question contained assumptions. It's got to have a lot to do with the fact that we kicked off the first week of class and their assignment by binge-reading "The Humans Who Went Extinct" by Finlayson. The book does a wonderfully broad treatment of the issues, but I was completely blind to the title's potential to inhibit nuance. If I'd anticipated this I would have discussed extinction much more during the course. [Consider this post, as so many are, an elaborate note to self.]

The trouble, as I see it, is it's unclear whether the Neanderthals went extinct the same way that we consider the Dodo to have gone extinct or the same way that dinosaurs (except birds) did at the end of the Cretaceous, etc.

Of course there aren't any Neanderthals alive now. But there aren't any australopiths alive now either and nobody's talking about australopith extinction.  Australopiths begat or, if you'd rather, evolved into Homo. Ardipithecus didn't go extinct either.  As of now we think and say that they evolved into (or, e.g., are in an ancestor-descendant relationship with) Australopithecus.

Aside from Neanderthals, Paranthropus is probably the only other hominin taxon that we discuss in terms of extinction. If its phylogenetic position is correct (and there is no dispute that I know of beyond the debate over one or two genera), then it left no living descendants and faded from the fossil record about a million years ago during a time when many other sub-Saharan fauna disappeared too. But these creatures were weird little bipedal apes, not stocky and muscular, big-eyed, big-nosed, ginger-haired, complexly cultured Europeans as the Neanderthals seem to have been. It's obvious to me why we obsess over the demise of the latter and not the former.

Anyway. Point is. I think we're being a bit intellectually reckless assuming Neanderthal "extinction." To me the question of their fate is more fairly posed "What happened to them?" with a strong answer being extinction but with a kind of extinction that needs to be carefully defined.

In order to hold the Neanderthal demise apart as special, as an exclusive story of "extinction," it needs to be shown that other long-dead LSA/UP hominins that we don't call "Neanderthals," but that we might claim as our more direct ancestors, didn't go "extinct" or have no story of extinction to tell. Don't you think?

[Aside: Here's where questions of cultural demise vs. continuity that are being addressed by archaeologists really might help. But again, we face problems because we know from modern examples that culture change does not equal genetic change and culture stasis does not equal genetic stasis.]

Further, and probably more significant here:  If Neanderthal "extinction" is the answer then it needs to account for the factoid that 23andMe says I have 2.9% Neanderthal (77th percentile for site users) in my genome which, as a Homo sapiens, is already more than 99% the same as a Neanderthal's.

There are at least 12 people who are more Neanderthal than I am.

I know that's confusing. I read the 23andMe methods paper, which is supposed to be simpler than the published one, but I still don't understand much about how they make the estimate.

Basically, it's about a percentage of SNPs (single nucleotide polymorphisms, a.k.a. mutations) that I share with dead Neanderthals but that so many live Africans (who I'm more closely related to!) do not. Therefore, if the methods are generally good, my genome contains evidence that people in my ancestry mated with Neanderthals. People who do not have these mutations either (a) never had Neanderthal mutations flow into their ancestors' families, or if they did  (b) those Neanderthal mutations drifted away before science could capture them from descendents today.

[You only got one mutation from mom and one from dad, the other part of the pair in each parent that you didn't get are dead ends (extinct!) unless your siblings or cousins got them. So a lot of SNPs and other variants disappear regularly and, on the other hand, everybody has new variants compared to their parents thanks to constant mutation.]

Tendrils of my ancestry must have been much more Neanderthal than 2.9%, but those SNPs drifted away over time. In other words, far enough back there had to be at least one hominin with a 100% Neanderthal genome in my ancestry (whatever that means), because that's the only way the genes got to me in the first place...but now they're diluted down, drifted away, and maybe even selected against to end  up 2.9% in me. I think that's about right.

These findings, that many people like me with ancestry from the northern hemisphere share small percentages of their DNA with Neanderthals, are not at all surprising to me. And that's for a couple reasons having to do with what we know about Neanderthals at this moment in scientific history, which in turn has a lot to do with why I titled the post the way that I did, which in turn has to do with my love of Young Frankenstein, and I think it's fairly common to think of Frankensteins and golems in the same imagination space as Neanderthals...

Walk this way

People are still studying Neanderthal feet and limb proportions to try to estimate energy expenditure during locomotion. But since we stopped basing all our reconstructions off an old man with arthritis, and a bunch of badass bone breaks that healed, we've accepted that Neanderthals are not clumsy, knuckle-draggers. They were good bipeds like we are--just coming into dangerously close contact with dinner and surviving well enough to string out their suffering before death.

Talk this way

Whether they had language is more of a lingering question but still one that's lop-sided towards yes, with the caveat that it probably wasn't as diverse and therefore wasn't as complex as ours. New research on a Neanderthal hyoid (small horse-shoe shaped bone in our throats that moves when we swallow and speak) claims that its structures reflect speech mechanics. But I really like reading about the work by Lieberman and McCarthy (written about broadly here) that explains how the Neanderthal throat and mouth dimensions probably did not allow for the tongue to move as much as ours does to manipulate expired air. This is how we make different vowels. Lieberman and McCarthy suggest Neanderthals couldn't have made as many distinct vowels as us and probably were as limited as human children in that regard. (Immature throat and mouth dimensions contribute to why kids sound like accented foreigners while they're developing.) Without as many vowel options their vocabulary would have been limited, but not non-existent! Surely they could produce something approximating this, no? Which brings us to...

Roll in the hay

So if it walks like a human, and sort of talks like a human, it probably bleeps like a human too. And our imaginations needn't feel naughty for going there since I already told you, if the methods are good, I carry evidence in every cell of my body that at least one of my ancestors waited until marriage to lose her virginity to a Neanderthal. (If you do want to feel naughty, read Ken's two recent posts here and especially here.)

***

They're so much like us or we're so much like them that we can't always tell their bones from ours! For a fascinating story on this, see Stephanie Pappas's piece "'Neanderthal' Remains Actually Medieval Human."

And yet you might see the latest news of "Neanderthal fossil indicates incest was common" which is about this article and say,  Hey! We're not like those incestuous savages! But ... well.. yes we are. We so are. And remember, we don't exactly have this kind of information from fossils that we welcome under the Homo sapiens umbrella and if we did (or when we do) I can all but guarantee we'll be finding some skeletons in those skeletons' closets too.

Neanderthals even took time away from incest to behave in some other pretty amazingly human ways. Scroll down to the bottom and check out what scientists have discovered about Neanderthal behavior just over the last year in this 2013 roundup by Kate Wong.

So despite the shrinking barrier between us and them, that we continue to call them "Neanderthals," sets them apart from us. It sets them apart from the real, or at least more human-y, Late Stone Age and Upper Paleolithic human hominins who begat us, whoever they are. And there's such a long tradition of differentiating them from us that it's hard to break free of the mold and present their story any other way than cloistered off as just that: "Their" story and one that ended before any of them could write it down. So they must have gone extinct, yo. Poof.

No seriously, which is it? Are they like chimps or dogs to us now, or were they like The French or The Red Sox of their day?

Maybe they're something else that we can't fully understand unless we actually encounter one another. So the best anybody can do is bring them to life from the inanimate material they left behind.

And because this is the best we can do, and because the fascination will always fuel it, the Neanderthal enigma can only intensify with more discoveries. It's so satisfying to say something conclusive at the end.

The non-biodegradability of plastic and the evolution of the human hand

Yesterday, on New Year's eve, we reprised a post we had done a couple of years ago.  That was itself a follow-up to our previous day's post on the nature of evolutionary speculation and reconstruction.  Today, on the actual holiday, we follow up on yesterday's repeated installment.  Yes, you might conclude that we're getting desperate to fill our pages over the holidays!

Well that's not really so, because our two previous posts were intended to be humorous, but also to make a point that is completely serious: our biological nature is often attributed to forces of natural selection in arguments that, to put it bluntly, do not always reflect the tightest of scientific reasoning--indeed, 'explanations' that sometimes are just fitted to a strongly held prior belief, an assumption that is accepted but not tested.  We think that is often not good science, or even not science at all.

Because the points are so highly technical and relate to the key subject of understanding human evolution and our behavior in particular, we'll take them in order:

Plastic is not biodegradable
Plastics are polymers made from natural carbon compounds such as we (today) take from fossil fuels.  They are resilient molecules with strength and durability, which is why we use so much of them.  In particular, however, they cause an environmental problem:  they are not biodegradable.  Discarded plastic litters our garbage dumps, but also our beaches, roadsides, picnic sites, etc.  Perhaps only chewing gum lasts longer (at least, under desks and on movie theater floors).

Everlasting evidence of almost anything we use! http://www.debgoesgreen.com/?p=1349

Unfortunately, because plastics hardly degrade naturally, they last for thousands of years, and with current rates of use that means a huge litter problem, danger to wildlife, and unsightly vistas.  But there can be a beneficial side-effect of the non-biodegradability of plastics:  as has widely been pointed out, our plastic remains will tell future archeologists much about how we lived today!  By the same token, we can turn that to our advantage today, by seeing what plastics tell us about our own past--in particular, our evolutionary past, and in ways you probably hardly realized!

The human hand evolved 'for' something
A characteristic of human beings that has attracted a lot of attention from paleoanthropologists is our hand.  Our dextrous hand enables us to do many things, such as type, pick our noses, and use tools of various sorts.  It is so very handy, so to speak, that it simply must have had some origin due to natural selection.  It couldn't have evolved just by chance.

Yesterday, in a reprise of a post from 2011, we examined the clearly dextrous nature of the fossil hand-bones of the species named Australopithecus sediba.  We argued that the species was wrongly named, in articles that hyped its importance in some ways on the thinnest kind of evidence.  In particular, the long-fingered hand was assumed to be related to early evidence of tool use, despite the minor irritating detail that no tools were found at the site.

The ritual explanation for the human hand's evolution, as an adaptation for tool use, that is offered by anthropologists shows aspects of our culture more than it does of our understanding of evolution.  Natural selection works only if a trait's presence leads to greater reproductive success than its absence.  That means that, whatever the reason, the hand must have evolved (if selection was involved) for some use that increased reproductive success.  Aesthetics alone would not be enough!

The usual handy explanation. Source  

Instead of tool use, we suggested that it was equally, if not more plausible that the hand evolved for its usefulness in masturbation.  Self-pleasuring is a way of generating sexual excitement and readiness, we noted, and would be thus very closely connected to reproductive fitness.  It's a much more direct and hence plausible explanation for the origin of the dextrous hand than is the ability to hurl rocks at fleeing wildebeests or to bring down a bunch of berries otherwise too high to reach by mouth.  So we suggested that the species would be better named Australopithecus erotimanis, to recognize the fundamental role that self-attention played in the evolution of our hands (that, we quickly acknowledge, most clearly were used for tool-making at some later time in our evolutionary history).

Now, one might argue that to suggest that our hand evolved for self-enjoyment was demeaning or silly, trivializing the gravity of the need for true evolutionary explanations.  But this is not because the argument was weak--after all, sexual arousal is even more closely tied to reproductive success than hunting and gathering by stoned ancestors, which might just have evoked laughter in their intended prey.  But topics, or even words, like 'masturbation' are awkward in our society and not likely to be taken seriously in real science....or are they?

To make our point, back to plastics!  We wanted to stiffen our discussion of the use of the hand, based on the actual evidence of the A. sediba finds.  So what could plastics possibly have to do with it?

The plastic tool--that wasn't!
We launch our argument by noting that the original sediba investigators essentially inferred tool use among the creatures they found, despite the absence of tools at their fossil site.  But even the tool-use assumption has been made impotent, one may say, by the restricted definitions that are applied, by which 'tool' refers to hunting, gathering, or warfare.  It may seem natural, but as default arguments so often do, that has become such a reflex explanation that it led investigators to fail to recognize the vital importance of what else wasn't found at the site!

We ourselves fell into the trap.  We failed to mention, in our original post on these finds, that not a single dildo or vibrator was reported among the artifacts at the erotimani site.  Yet, as we noted above, plastics are not biodegradable.  If our ancestors had been using their hands to wield those tools for self-stimulation, surely we would have found them!  But neither their casing nor any of their metal electronic parts (the ones that vibrate) were found.  Not a trace!  Not even a travel case!

Now this is as hard a piece of evidence as one could want for our hypothesis.  Unlike the absence of stone tools and tool-use, the absence of vibrators shows that they must have been using their hands--not tools.  Supporting this fact is that not only were there no stone axes, but there were no stone dildos, either, which of course would have survived to be found today.   You might say that, as practiced tool-users, the erotimani would perhaps have fashioned wooden ones instead of stone, and wood would have decayed and not be found today.  But that argument doesn't hold (so to speak), because wooden ones would have led to very painful splinters which certainly would not have been good for reproductive behavior.  Ouch!

The best explanation must be true....mustn't it?
Now there is so much of a tendency to offer, and uncritically to accept, just-so adaptation stories, that surely we must agree that one of them must be the true one.  But how do you decide which is best?  And why would our effort at explanation be dismissed out of hand, so to speak?  How can one assert that we have not fingered the truth?  Perhaps the reason is not scientific at all, but instead is cultural--reflecting both our need for simple explanations and our particular sensitivities.  This possibility is easy to see.

If someone were to find a structure in beetles, or even oysters, that the organisms routinely used to stimulate their genital organs, and this were related to reproductive behavior, the evolutionary argument would be totally compelling and would be front-page material in the Times and Nature or Science.  Do you doubt that?  So why not in humans--unless this is about our cultural squeamishness rather than science!  Hunting tools are respectable in mixed company in our society, but humping tools aren't.

Upon close inspection, and seriously, our explanation is in every way as good as the usual ones.  We didn't write it just to wet--or rather, whet--your appetite with our suggestive, er, post (sorry! Many words on this topic have potential double entendres, and I'm finding it very hard to work on my post, which drains the pleasure out of it).  Think carefully about how present-day behavior is typically assumed to be the past's selective reason, about the often near total lack of actual evidence for invoking a specific adaptive explanation, especially in regard to vague things such as behavior, but often about structure as well.

So, we challenge anyone to seriously say that our explanation is not at least as good, and at least as closely tied to evolutionary fitness--that is, reproductive success--as other explanations.  On what grounds?

Life is complicated by the fact that most structures have more than one function today, and not all of them need have evolved at the same time, though the tendency is to pick one of them and insist it was in the long, distant past the reason for the structure's existence today.  Fragmentary or statistically weak evidence, today or from the past, is too often accepted if a nice story can be told by it.  We think this isn't the best that science should offer and that, except perhaps in sexual affairs, restraint would be a better policy.

Even indirect evidence, such as the non-biodegradability of plastic, may tell the tale.  You never know.

Happy New Year, MT Readers! Here's a holiday treat from the past

What?  What are you doing here, on a holiday eve?  Perhaps you're bored, web-browsing while waiting to become thoroughly plastered later tonight?  Or, at least waiting to watch the ball drop in Times Square.  Well, we here at MT thought that as a pre-holiday service we'd bring you an echo out of our own modest past. We seemed to have aroused a stir with yesterday's foray into the wild territory of wild explanations about behavior. That forced a bit of reflection and soul-searching on our behalf, which we'll try to correct with a bonus post today.

The fact is that yesterday's post seemed to elicit a bit of confusion, or even anger, about what we are up to here at The Mermaid's Tale, at least with respect to our views on evolutionary psychology and behavioral evolution.  We were even accused of being so opaque as not to understand or even believe in evolution!

So, in an effort to show that we're in fact Equal Opportunity critics, we thought we'd solve your pre-holiday boredom by rustling up this old post of ours (from 2011), that showed how absolutely open-minded we are, except that instead of explaining live behavior, we examined explanations for past behavior, based on paleontological evidence.  This should make it crystal clear that we certainly value, indeed even offer, evolutionary explanations.
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From the very beginning of formal taxonomy in biology, genus and species names have been assigned partly as descriptions of important aspects of a species.  Hence, Homo sapiens refers to our species' purported wisdom.  The underlying idea is that one correctly understands important key functions that characterize the species.  Linnaeus did not have 'evolution' as a framework with which to make such judgments, but we do.  And we should use that framework!

However, sometimes, in the rush to publish in the leading tabloids (in this case, Science magazine), a name is too hastily chosen.  That applies clearly to the recently ballyhooed 1.9+ million year old South African human ancestor.  Substantial fossil remains of two individuals, a male and a female, were found and seemed clearly to be contemporaneous.  Many features suggested that they could be marketed as a Revolutionary! revision to our entire understanding of human origins.

Now, too often in paleoanthropology there is little substantial evidence for such a dramatic consequences, similar to the pinnate carnage known as the War of Jenkins' Ear between Britain and Spain in 1739.  But not in this case here!   In this case, the specimens were dubbed Australopithecus sediba (See the special issue of Science, Sept 9, 2011 [subscription required]), and there are many traits, some more dramatic than others, by which to argue that it is Really (this time) important.

We haven't the space to outline all these features, but although we are amateurs at paleontology (for expertise, we fortunately have Holly the Amazing Dunsworth as part of our MT team), we feel qualified to comment.  One of the most remarkable features of A. sediba is its long, delicate digits on its obviously dextrous hand, and in particular its long and clearly useful thumb.  But useful for what?

One who is rooted, or rutted, in classical human paleontology, and thinks that tool use is what Made us Human, the obvious inference is:  a dextrous hand for tool use!   There is, however, a tiny problem: no tools were found in the site.

Now this can be hand-waived away in defense of the explanatory hypothesis that is derived from classical adaptive thinking.  Wooden tools, like stems chimps strip and use to ferret out termites, wouldn't preserve, and at that early stage of our evolution, stone pebbles might have been used--or even made--but would be perhaps sparse and if not remodeled by the creatures, unrecognizable.  Or perhaps these creatures hadn't carried their tools to the site.  There may indeed be perfectly reasonable explanations for why no tools were found, but one must at least admit that the absence of tools does not constitute evidence for the tool hypothesis.

Still, if you believe there must be a functionally adaptive explanation for absolutely everything, and you are committed to the current framework of explanations about our ancestry, then tool-use is the obvious one.  How occasional use of pebbles led to higher reproductive success--which, remember, is what adaptive explanations must convincingly show--is somewhat less than obvious.  Also, it is the female specimen whose hand is best preserved, though the male is inferred (from one finger bone!) to have been similarly handy.  But females don't throw pebbles to gather berries!

A satisfying explanation
So how solid or even credible is the tool-use explanation?  Could there be better scenarios? We think so, and we believe our idea is as scientifically valid as the tired old one of tool use.

It is obvious upon looking at the fossil hand, that its most likely purpose was, not to mince words about it, masturbation.  Just look at the hand itself and its reach position (figure 2).  Think about it:  deft and masterly self-satisfying would yield  heightened sexuality, indeed of keeping one's self aroused at all times, ready for the Real Thing whenever the opportunity might arise. Unlike having to wait for prey to amble by, one could take one's evolutionary future in one's own hands--and use one's tool in a better way, one might say.

Being in a dreamy state is a lot less likely to provoke lethal strife within the population nor "Not tonight, I'm too tired" syndromes, compared to the high-stress life of hunting giraffes (much less rabbits) or trying to bring down berries, by throwing chunky stones at them.  Our laid-back scenario does not require fabricating stories of how rock-tossing indirectly got you a mate, because pervasive  arousal would be much more closely connected to reproductive coupling, a way of coming rapidly to the important climax: immediate evolutionary success.

Indeed, and here is a key part of our explanation, the same fitness advantage would have applied to both the males and the females.  If both parties were at anticipatory states more of the time, fitness-related activity would have occurred even more frequently than it does now, if you can imagine that, and quickly led to our own very existence as a be-thumbed if not bewildered species.

Supporting our hypothesis, vestiges of the original use are still around, as for example the frequency with which football and baseball players grab themselves before each play.  Of course, humans seem subsequently and unfairly to have evolved to be less gender-symmetric in this regard.  But our explanation is far better than the tired stone-axe story-telling with which we're so familiar.  For this reason, we suggest the new nomenclature for our ancient ancestor:  Australopithecus erotimanis.

Now, you may think our scenario is simply silly and not at all credible.  But is it?  By what criterion would you make such a judgment?  Indeed, even being silly wouldn't make it false.  And, while you may view the standard Man the Hunter explanation as highly plausible, being plausible doesn't make it true. Nor when you get right down to it, is the evidence for the stone-age hypothesis any better than the evidence for our hypothesis.

Indeed, if you think carefully about it, even the presence of some worked pebbles would not count as evidence that hands evolved for tool use.  The dextrous hand could have been an exaptation, that is, a trait evolved in some other context, and then later was co-opted for a new function--in this case, the flexible hand, once evolved for one use, could then be used to make and throw tools.  What we have explained here is the earlier function that made the hand available in that way.

Don't laugh or sneer, because this is actually a not-so-silly point about the science, or lack of science, involved in so much of human paleontology.  It's a field in which committed belief in the need for specific and usually simple adaptive scenarios, using a subjective, culture-specific sense of what is  'plausible', determines what gets into the literature and the text-books (though our idea might have a better chance with National Geographic).

Will anthropology ever become a more seriously rigorous science, with at least an appropriate level of circumspection?  It's something to ponder.

"Italians are lovers, not fighters!" -- genes, behavior and ideology

In what now seems like a long time ago, I was an Air Force weather officer, stationed at a NATO base in England.  One of my fellow forecasters, Gus Leshner, the best forecaster I ever met, was a Warrant Officer who had fought in WWII in Italy.  He once told me that, in a wartime discussion with some Italians just after their country had rather easily surrendered, one of them told him rather unembarassedly that Italy lost because "We Italians are lovers, not fighters."

At the time, and in its context, that story seemed an apt metaphor for Italian culture as we saw it at the time.  Gus told me a few of his other war stories while we finished working up the morning forecast for the swarm of pilots who would shortly call for their pre-flight briefings.

I never thought about his quip except as an apt description of a rather weak military country that is loaded with culture--sculpture, opera, paintings, intellectual movies, fantastic food, and people who talk by waving their hands.  Organized crime aside, it's a warm and appealing image, and it befits Anne's and my wonderful son-in-law, a native of that land.

But then along came sociobiology....

In their genes
Sociobiology is one of several names for that field of biology (evolutionary psychology, known as evo psycho by some, is another) that seems to think that everything we do or say is mandated by our inherited genomes (sometimes, possibly affected in minor ways by the environment).  Even our culture itself is the product of our genes. Our genes make us do what we do, and if we do it well, our population proliferates (as a corollary, behavior has Darwinian-based values that proponents of this view can easily identify).  You may know how the theory goes, as it's all over the news media.

A few decades ago, , as I recall, Robert Ardrey, an author about as highly qualified as Richard Dawkins to write about the nature of life, proclaimed about Italians that their honking, fist-shaking impatience in traffic (another clearly inherent trait, as you know if you've ever tried to actually drive in Italy) was part of their genetic make-up (Ardrey was a playwright, so that, like others of his scientific ilk, inventing fiction was his specialty).

Well, when it comes to the lusty Italians, one can't resist conjuring objects of what's in their (excitingly tight, body-hugging) jeans as well as genes, given various memorable cinematic and statuary representatives of their genome.  The Land of Lovers!  Soft violin music, or a Verdi aria in the background, a glass or two of Valpolicella, and....well, one's imagination is hard to control.

But wait--isn't, um, Rome in Italy?
When these thoughts pass, we find that we've got some reconciling to do: the image of the pacific Italian lover vis-à-vis the Romans (who were from Italy, as we recall).  They were for many centuries the dominant military power, by unrepentant force of arms controlling the biggest empire the world had known (til the Brits came along, and nobody ever accused them of being lovers rather than fighters, given their gloomy climate).

Tough guys, or sissies?: http://annoyzview.files.wordpress.com/2012/03/roman_soldier_1.jpg

Romans with shields, chariots, wielding their swords (in combat, that is)!  They had oval chariot-combat arenas, and gladiatorial combat centers (coliseums, probably named after food-brands or insurance companies now lost to history).  They slaughtered vicious lions to prove their mighty valor, and slaughtered each other to prove their, well, I'm not sure what, but it certainly wasn't about love!

Now, I have myself seen these scenes of brutality in many places, and have read about what happened in them, even in books by authors from that time (e.g., Galen, one of whose important jobs was fixing up gored and sliced gladiators, and another was taking care of the slashed and stabbed soldiers of Emperor Marcus Arelius), and in Charlton Heston movies.  The Romans were rather nasty beasts.  If the classics are anything to go by, a favorite sport was crucifixion.

But then how is this possible?  I mean, everyone's heard about lovers' spats, but this seems rather different!

The Roman empire fizzled out only about 1500 years ago.  Maybe some Jews and a few other stragglers from the Middle Eastern part of the Empire, or Turks and their like, ended up in Italy as that fizzling happened.  But, hostility to immigrants being what it is (and, sociobiologists would tell you, it's inherently genetic), these drifters certainly didn't replace the Romans and their seed.

But, if we're to believe the story told by the likes of evolutionary psychologists, the very same population that is now amorously pacific by nature was once quite violent.  So how on earth did the requisite nation-wide genome replacement take place, and how were gladiator genomes exterminated by the soft-and-sexy, artsy ones that now fill the Mediterranean boot?

Our inclination is to venture to say that culture is not, after all, in our genes, and that genes enable all sorts of behaviors, but don't prescribe them.  But that must be wrong, because so many anthropologists and others who should know, assure us that what we are can be read off a DNA sequencer.  Indeed, we hear tell of a new book, due out in the spring, by a New York Times 'science' (op/ed?) writer of a particularly determinist persuasion that will insist that this is so.

To quote Thomas Huxley in 1891, an acerbic critic of religious orthodoxy who, even back then and unlike many of their lot today, actually understood evolution, himself quoting Goethe from 1833; "There is nothing more terrible than energetic ignorance." [Huxley, 1891, "Hasisadra's Adventure".]

It's going to be a long, hot spring.

Wishes for the new season, in old verse.

Even in science, which is supposed to be objective, and should be objective, there are times when feelings and interactions are not consistent with that ideal.  Scientists, as any other group of humans, often disagree passionately and as a result, can treat each other coldly. 

We offer you on this Christmas day an 1888 verse by the wonderful pastoral poet William Wordsworth, who made his points in ordinary language so as not to be exclusive about his subject or his readers.

The point, for scientists, is that we needn't hoard our every idea or result, even ones we're no longer using, against those who might gain warmth from their use.

We may differ about what is right or wrong in science, but we know what's right in how we regard each other, so let neither our acts nor our wishes set each other's teeth achatter!

Goody Blake and Harry Gill

Oh! what's the matter? what's the matter?
What is't that ails young Harry Gill?
That evermore his teeth they chatter,
Chatter, chatter, chatter still!
Of waistcoats Harry has no lack,
Good duffle grey, and flannel fine;
He has a blanket on his back,
And coats enough to smother nine.

In March, December, and in July,
'Tis all the same with Harry Gill;
The neighbours tell, and tell you truly,
His teeth they chatter, chatter still.
At night, at morning, and at noon,
'Tis all the same with Harry Gill;

Beneath the sun, beneath the moon,
His teeth they chatter, chatter still!

Young Harry was a lusty drover,
And who so stout of limb as he?
His cheeks were red as ruddy clover;
His voice was like the voice of three.
Old Goody Blake was old and poor;
Ill fed she was, and thinly clad;
And any man who passed her door
Might see how poor a hut she had.

All day she spun in her poor dwelling:
And then her three hours' work at night,
Alas! 'twas hardly worth the telling,
It would not pay for candle-light.
Remote from sheltered village-green,
On a hill's northern side she dwelt,
Where from sea-blasts the hawthorns lean,
And hoary dews are slow to melt.

By the same fire to boil their pottage,
Two poor old Dames, as I have known,
Will often live in one small cottage;
But she, poor Woman! housed alone.
'Twas well enough when summer came,
The long, warm, lightsome summer-day,
Then at her door the 'canty' Dame
Would sit, as any linnet, gay.

But when the ice our streams did fetter,
Oh then how her old bones would shake!
You would have said, if you had met her,
'Twas a hard time for Goody Blake.
Her evenings then were dull and dead:
Sad case it was, as you may think,
For very cold to go to bed;
And then for cold not sleep a wink.

O joy for her! whene'er in winter
The winds at night had made a rout;
And scattered many a lusty splinter
And many a rotten bough about.
Yet never had she, well or sick,
As every man who knew her says,
A pile beforehand, turf or stick,
Enough to warm her for three days.

Now, when the frost was past enduring,
And made her poor old bones to ache,
Could any thing be more alluring
Than an old hedge to Goody Blake?
And, now and then, it must be said,
When her old bones were cold and chill,
She left her fire, or left her bed,
To seek the hedge of Harry Gill.

Now Harry he had long suspected
This trespass of old Goody Blake;
And vowed that she should be detected--
That he on her would vengeance take.
And oft from his warm fire he'd go,
And to the fields his road would take;
And there, at night, in frost and snow,
He watched to seize old Goody Blake.

And once, behind a rick of barley,
Thus looking out did Harry stand:
The moon was full and shining clearly,
And crisp with frost the stubble land.
--He hears a noise--he's all awake--
Again?--on tip-toe down the hill
He softly creeps--'tis Goody Blake;
She's at the hedge of Harry Gill!

Right glad was he when he beheld her:
Stick after stick did Goody pull:
He stood behind a bush of elder,
Till she had filled her apron full.
When with her load she turned about,
The by-way back again to take;
He started forward, with a shout,
And sprang upon poor Goody Blake.

And fiercely by the arm he took her,
And by the arm he held her fast,
And fiercely by the arm he shook her,
And cried, "I've caught you then at last!"--
Then Goody, who had nothing said,
Her bundle from her lap let fall;
And, kneeling on the sticks, she prayed
To God that is the judge of all.

She prayed, her withered hand uprearing,
While Harry held her by the arm--
"God! who art never out of hearing,
O may he never more be warm!" 0
The cold, cold moon above her head,
Thus on her knees did Goody pray;
Young Harry heard what she had said:
And icy cold he turned away.

He went complaining all the morrow
That he was cold and very chill:
His face was gloom, his heart was sorrow,
Alas! that day for Harry Gill!
That day he wore a riding-coat,
But not a whit the warmer he:
Another was on Thursday brought,
And ere the Sabbath he had three.

'Twas all in vain, a useless matter,
And blankets were about him pinned;
Yet still his jaws and teeth they clatter;
Like a loose casement in the wind.
And Harry's flesh it fell away;
And all who see him say, 'tis plain,
That, live as long as live he may,
He never will be warm again.

No word to any man he utters,
A-bed or up, to young or old;
But ever to himself he mutters,
"Poor Harry Gill is very cold."
A-bed or up, by night or day;
His teeth they chatter, chatter still.
Now think, ye farmers all, I pray,
Of Goody Blake and Harry Gill!



And now here's another from Wordsworth...
in a more cheerful vein! 

Make it Snow!

The minstrels played their Christmas tune
To-night beneath my cottage-eaves;
While, smitten by a lofty moon,
The encircling laurels, thick with leaves,
Gave back a rich and dazzling sheen,
That overpowered their natural green.

Through hill and valley every breeze
Had sunk to rest with folded wings:
Keen was the air, but could not freeze,
Nor check, the music of the strings;
So stout and hardy were the band
That scraped the chords with strenuous hand.

And who but listened?--till was paid
Respect to every inmate's claim,
The greeting given, the music played
In honour of each household name,
Duly pronounced with lusty call,
And "Merry Christmas" wished to all.

Thumbs up...and heads down. More on 'selectionism'

Last week we used my glorious thumb and its several properties to illustrate the difficult problem of defining what a biological trait is, in relation to the widely held assumption that our traits are here strictly because of natural selection.  Our point was that it is quite tricky to define a trait, or specify just how precise, and in what ways, our assumed selection has worked, and is working.

A thumb is seemingly so simple that it can be surprising how difficult this is.  But here is another 'trait' that is clearly an evolved trait with what even I would agree is of fundamental importance to our existence, and in that sense, 'adaptive': the skull.  It, if it is an 'it', clearly has evolved and using evolutionary theory and comparative anatomy, we can identify what we assume are evolutionarily corresponding 'landmarks' (the dots in the figures below).  These are canonical anatomical locations shared by members of a species, but the distance between them varies within and among species.  These measures can be indicative of genetic and/or life experience variation.  But is the skull, or a landmark, the product of natural selection?  To answer that question, we must understand what 'it' is.

Landmarks: human, baboon, and mouse (Figure by Joan Richtsmeier)

This example is courtesy of work with our long-time collaborator (and good friend) Joan Richtsmeier, an expert on imaging and analyzing craniofacial dimensions and their pattern of variation.  Indeed, the figure shows various standard measures that people in this field use.  We and Joan, and Tim Ryan also in Anthropology here, along with Jim Cheverud of Loyola in Chicago, Heather Lawson at Washington University Medical School, Jeff Rogers at Baylor College of Medicine, and others, have been looking at the genetic contributions to craniometric traits in laboratory mice, and in a big baboon genealogy housed in Texas, and to compare that with what is known about human skull-shape variation.

We have CT scanned the skulls and made careful identification of standard 'landmark' points, the dots in the figure (the Figure just shows whole skulls, but in a CT scan the landmarks can be in 3-Dimensional locations and we can look at any slice through the object).  Then, using hundreds of individual skull-scans, we have been relating inter-landmark distances (lines that can be drawn between any two landmarks) to genetic variation, to 'map' the genomic locations that affect each distance's (or correlated distances') variation.  Yes, skeptical though we are of its over-interpretation, we are using GWAS-like methods (QTL mapping) to do this.  (We've described the difficulties with this work a few times on MT, including here and here.  The gene mapping issues we discussed in these posts remain unresolved.)

We chose the landmarks and distances based on what has been done before, or reflecting obvious locations like where sutures join or peaks in curvature and so on.  The statistical methods in the genomic analysis and so on are also well-tested (there are some controversies but they're beside the point, or comparable to the point that we're making here).  For most of the landmarks in one species, homologous locations can be found in the others (in our work, humans, baboons, and mice).  In this sense, the distances are very clearly 'objective,'  replicable measures of shape and size in the skulls.

But in what sense are they 'traits'?  Is the fact that we can identify and measure them, for reasons we decide on, a sufficient basis for the definition of a trait?  Is a measure's genomic 'control', regions that we identify by mapping, actually 'for' that measure?  If so it implies that other aspects of skulls, such as the bone thickness, dental cusp or shape patterns, and so on, are unrelated and irrelevant to the measure.   That seems hardly to be justified.

We know these traits evolved and that what we observe today ancestrally had to be consistent with successful survival and reproduction--passing the screening of natural selection or whatever other types of functional trials were imposed.  And they survived chance events, too.

But just as with the thumb example from Friday's post, it is we the  investigators who decide what a 'trait' is, and if we wish to infer adaptive scenarios it is we who decide what is adapting.  That leaves us the freedom to decide with equal subjectivity what it was adapting for.  Of course we know that other aspects than what we're testing had to have evolved consistently with what we're testing, or else a single, functionally viable and cohering skull would not have developed in the ancestral individuals as they and their various craniofacial 'traits' (whatever they be) were evolving.  But of the countless genes expressed in, and hence clearly contributing to, skull development, how is it that we can decide if the gene is 'for' some particular distance measure?  A gene may contribute to that strictly via some other effect than what we think our measurement is about (indeed, what 'strictly' means is itself questionable).  Indeed, most genes contribute to many different tissues and structures and developmental stages in the head, not just one.

Here, we're not just playing possibly-trivial thumb games, but are considering the nature and evolution of one of our most vital structures.  Yet the same question: what is a 'trait'? arises in regard to essentially every distance we assessed and to the very act of choosing landmarks and distances to measure.   So what we are really considering is the nature of evolution itself.

Chance is a chancy subject because it, and associated 'probability' are very hard to define.  But even if chance has, and always had, nothing to do with our 'traits', and if selection really were, as so often asserted, the be-all and end-all of life (except, of course, for love and lunch), and even if we've had Darwinian ideas for more than 150 years, and even if they were wholly correct, then even then, natural selection and the nature of evolution are still far from completely understood.

Somehow, however, many of people in evolutionary biology don't seem to realize this, or don't want to acknowledge it.  Or don't they care about truth, so long as they can tell a good story?

"Every trait is due to natural selection!"....often said, but is it true?

It is often said by people who claim to understand evolution that every trait is due to natural selection.  This is belief in a form of very strong determinism that reduces, in essence, to genetic determinism.  It's closely akin to the confident defense of the pop-culture concept of the 'selfish' gene against all challenges.  Put another way,  in such a view, natural selection is not a scientific statement about evidence, but an axiom--an assumption--that is used to make inference from data, but not something to be tested in itself.

For reasons we'll go into, it's not entirely clear where this view comes from, but it's often justified as a form of materialism, as if Genesis According to Darwin is true and therefore selection is the proper riposte to Genesis According to God.  But it's highly misplaced in science, and the assumption obscures an actual discussion.  Let's agree that if we'll stay within the confines of materialism--that is, no mysticism and that the laws of physical nature must  not just be consistent with, but must also ultimately explain, everything biological--we can examine the nature of strongly determinstic Darwinism.

So let's consider the proposition that every trait is due to natural selection.  We'll use an example.  First we need a trait.  Ok, here's a picture of my thumb (not used out of vanity over its undoubted beauty!).  Is 'it' a 'trait'?  If it is, of course, we can speak about 'its' evolution.  If it's not a trait, then what is it and how can we understand it?

Thumbs up...or angles out....or....?

On second thought, maybe the whole thumb is not a 'trait'.   Maybe it's the angle,  θ, the measure of the bend where the second phalanx starts.  Or is the trait that my thumb has a second phalanx?  Or that I can make that angle?  Or is the trait the length, x, of the second phalanx?  Or the angle between the thumb and the first finger?  How do we decide?  All of these traits or parts of traits have in some way evolved together, so it's hard to say when one aspect begins and another one ends, that is, what is the 'trait'.

But let's say we make our decision on that question.  Then, if whatever we decide our trait must, by the usual assumption, have evolved by natural selection, we want to be able to say what it evolved 'for'.  And to do that, we must show that the trait we're assuming resulted from natural selection somehow had direct fitness (survival or fertility) effects, because, since to selectionistic explanations chance is not an option, differential fitness is the mechanism by which natural selection works.  If our trait is θ, that means that if my ancestors had had an intrapollectial angle (pollex means thumb in Latin, and therefore using the word makes it 'science') that was--what?--greater than my θ, or was it less than my θ, or was it enough that it wasn't exactly my θ?, then they didn't have any kids and I wouldn't be here!

But wait!  What if the trait was the length of the distal pollectial segment, x, that mattered.  Those ancestors with more stubby thumb-ends are fossils without issue (that means, by the way, that when paleontologists dig them up they can't interpret what they were adapted for, since the death was because they weren't adaptive).  Or maybe those with gross thumbs whose last digit was a tad too long (how much is too much--one millimeter, say?) died out.  The trouble of course is that even my adaptive distant ancestors are dead, and how can we say whether they were 'fully' adaptive and died after having many kids, or were just caught by a lion when they wandered carelessly away from the campfire to take a pee one night (we don't need to consider whether, perhaps gender-related, the thumb trait was involved in that latter process).

Now given my important pollectial triangle (here we consider θ and x to have jointly been the critical 'trait', though what justification there is for that is an open issue), our task is to understand what natural selection molded it for.

The obvious thing is to look at what we actually do with our thumbs (that requires a triangular configuration like mine).   Most anthropologists will argue that our thumbs are for tool use--at least, it says that in textbooks about thumbs, so it must be true.  But I know that my deep ancestors didn't have pens and pencils or space-bars to tap, so it must have been for throwing stones in annual sporting events where the winner impressed the girls and, well, you know....

What about holding a rake in the fall when I clear my yard of leaves---it couldn't have been for that because my ancestors evolved in Africa where you don't have to rake leaves in the fall because it's tropical and there is no fall!  No, I have to think of uses that aren't just modern exploitations of a trait that was strongly selected in the past for something they did in the past.  This is a bit now-centered, because in the past the use of the traits they had then might not have been for what they did then, but what their ancestors did in their distant past.

Anyway, I suppose since the trait must have had important fitness-related function, if it is assumed to have evolved by natural selection, it may have had a role in sexual stimulation of some sort.  One can let one's imagination run wild, but we needn't go that far.  As I was saying, other than for modern uses, what I use my pollectial angle for is for getting itchy specks of dust out and sleep-grains of the corner of my eye.  Without that angle, θ, I wouldn't easily be able to do it.  Now on the dusty African savannah, when sharp-eyed spotting of  prey and aiming of spears or hunting-stones was vital, the eye-clearing use of thumbs is an obvious explanation.

There is the annoying little question of why not everyone's thumbs have exactly the same triangle--side length or angle.  If this is an adaptive trait formed by natural selection long ago, which it must have been since humans around the world have pollectial triangles (and so did Neandertals and even Denisovans!), then why is it still so variable?

Well, I'm getting tired of all this speculation.  This is especially unnerving because I can think of other aspects of thumbs that might be considered as traits, or the trait may be a complex of traits with their own individual selective reasons.  Or, really disturbing, these assembled aspects may have had different functions (that affected reproductive success) during the million years in which the trait(s) were adaptively evolving.

Now selectionist axioms don't provide room for probability in reproductive success.  That's why earlier I said that if my ancestors' value of θ was even a bit different from mine, then they must not have reproduced; if some tolerance was allowed, then fitness would be probabilistic, and that means chance, which is not allowed: the trait has to be functionally deterministic. That's because once you admit probabilities (genetic drift), you open the door to all sorts of less satisfying, less simple, and less clear-cut explanations--and Nature and the Times will shun your papers.  Part of the fear is that if one says a trait's presence is for 'random' reasons, it opens the door to creationism or, worse, lack of some explanation that's simple enough for undergraduates to understand or the research to be reported in the NY Times. It raises the specter of a 747 arising randomly out of a pile of scrap metal.

This is a silly non sequitur, since nobody (not even neutralists, who somehow can conceive of aspects of traits that arose for no adaptive reason at all) denies the role of various sorts of constraint, including classical natural selection, even when invoking genetic drift.  But it's just as silly to think that every tiny aspect of every trait has to be here because of specific natural selection in the usual sense.  Darwin rationalized various aspects of traits, such as correlations among them, basically as having developmental-constraint reasons and so on.  We know of such things in better molecular terms today.

More importantly, it is the definition of what counts as a 'trait' that we should be thinking more seriously about.  Organisms evolve as organisms, not just as sets of traits, and to the extent that a trait is in the eye of the definer, speculations about what it's 'for'  may also be just-so stories in the mind of the definer.  So is the use of selection as an axiom: if something (whatever that be) is assumed  to be here because of selection, then to say that it's here because of selection is a tautology.  The care one must take to avoid such tautological thinking has been known for many decades.  There are serious questions about evolution's mechanism that usually are swept under the rug because they point out inconvenient complexity that does not lead to convenient publishable answers. Who decides where a 'trait' s/he can define is or was a unitary phenomenon during its evolution?  And who decides how precise the hypothesized adaptation was?   And who decides how much of its variation may have been tolerated or even itself adaptive?

Trait micro-definitions, arbitrary post-hoc trait definition, and so on show by example how hard it is to legitimately decide what to include.  And if, as most of the evidence both theoretical and observational suggests, typical selective advantages are on the order of about one per thousand (you have 10001 kids with a good thumb-angle vs 1000 without such an angle), that is almost meaningless besides being literally impossible to prove.  It certainly means that traits with socially sensitive implications when interpreted in strong selectionist terms are, evolutionarily, essentially meaningless, as is the very notion that selection like that is a determinative 'force'.  Many such traits probably exist, and most traits may be like that, if we could even decide how to define them.  They should be deprived of their societal implications or value judgments, or much of the scientific surety with which the explanations are too-often couched.  Even mate-choice criteria, that could be very close to fitness, if the trait is used only now and then because there really wasn't much choice in human ancestral populations or kinship rules specified who you mated with, may mean little locally even if over long term the scenario is true.

The point about thumbs may seem like a kind of reductio ad absurdam, but is it?  Viewed from some time or vantage points, structures whose adaptive origins may seem obvious might be as problematic as my thumb from some other frames of reference.  For thousands of generations it could be that, say, the angle or size of the iliac crest would seem as trivial a 'trait' as my thumb, while today it seems fundamental to upright posture.

Fatigue wins....
I must confess that my patience is running low (that's one of my traits!), so I am simply ignoring the wrinkles in the thumb.  They may actually be the trait that evolved adaptively, though 'for' what is beyond me.  Probably I'm just tiring.  You can provide the explanation without my help, I'm sure.