Craniofacial Form and Evolution

It's time to give my preliminary review of the evolution of craniofacial form I've observed over the past six weeks.

Again, I've been to Lexington, KY, Springfield, IL and now Tucson, AZ, collecting shape data from prehistoric crania and mandibles from a number of Native American populations. My research is designed to test the hypothesis that the shift from hunting and gathering to agricultural subsistence resulted in decreased robusticity in numerous aspects of the crania and mandible. This is known as the functional masticatory complex hypothesis. The FMCH posits that the causal mechanism behind this trend of decreasing craniofacial robusticity, or craniofacial gracilization, is the transition to a diet consisting of a higher proportion of soft, processed foods. Simply put, according the the FMCH, an individual needs to generate less bite force to chew corn meal as opposed to nuts, seeds or dried meat. As a result, an agricultural diet places lower demands on the bones and muscles of the face than does a hunting and gathering diet. Thus, with the shift to an agriculture-based diet, the cranium and mandible became less robust through evolutionary processes or through the regular, developmental responses of bone, or through both. "Robusticity" is a term that paleoanthropologists have struggled to define. Loosely, it includes aspects of bone thickness, overall size, as well as the presence of certain "robust" features, such as pronounced bony browridges.

On to the review. After each paragraph, I provide labeled drawings which identify the anatomical points referenced in the text.

In Lexington, I studied a prehistoric population of Archaic hunter-gatherers. During this period, we see definite development and growth of features throughout the facial region. This growth extends from the zygomatic arches on the sides of the face, inferiorly down the mandibular ramus to the gonion of the mandible, and forward from there to the zygomaxillary suture, the alveolar areas of the maxilla and mandible, the mental eminence which marks the most anterior aspect of the chin, and gnathion, the most posterior aspect of the chin. But this development should not be viewed on a feature-by-feature basis. Rather, it is spread across the entirety of the face and jaw.

Now to Springfield, where I collected data on a prehistoric population which, over millenia, transitioned from hunting and gathering to a subsistence economy heavily reliant on maize agriculture. Here, after a period of relative stability or even growth, we do observe the total loss of developed features in certain regions of the face and mandible. This loss seems to take place in an abrupt, step-wise fashion. If evolutionary processes are at work, I don't yet completely understand them. In any event, the first disappearances are in smaller spots--at the alveolar region at or near upper first adult molar, and a sort of "trimming" in the upper cheek region, at and around the zygomaxillary suture. This is followed by similar but more broadly occurring phenomena of loss along the lateral corpus and lower ramus of the mandible. Mostly unaffected, however are (1) the alveolar region from the midline of the face to the canines, (2) the midline region of the jaw from the alveolar margin (infrandentale), through the mental eminence, down to the most posterior aspect of the chin (gnathion), and (3) development along the zygomatic arch and mandibular condyles. All of this seems to be a series of transitional forms on the way toward final manifestation.

Finally, in Tucson, I am collecting data on a prehistoric population of well-established agriculturalists. Here, we see only one substantial change: the complete loss of features of the chin (from the mental eminence to gnathion), except for retention at infrandentale.

Below I provide photographs taken during my six weeks on the road. This chronological sequence demonstrates the physical reality of what I've described above. And while we may all have different opinions of the end result, from brilliant to, well, cheesy, I suggest that we have reached for the foreseeable future what we in the business refer to as an evolutionarily stable state.

Lexington, early stage . . .

Springfield, early stage. Note: ALL SKULLS (EXCEPT MINE) ARE PLASTIC CASTS. NO DISRESPECT TO THE DEAD.

Springfield, transitional forms

Tucson, final form!

Postscript: Yes, I took some of these pictures of myself. But there was a journalistic purpose to it, I guess.

I'm back

I had bad Indian food today at the University of Arizona food court. It made me think of my friend Nikhil, who hasn't called me back, which makes him a bad Indian. Where are you NM?

If summer 1969 was the "Summer of Love," . . .

. . . summer 2009 may go down as the Summer of "Hey, what are your plans this afternoon?"

Two, not one but two couples I know well eloped in the month of August. Each couple has already been together longer than most marriages last, which I think bodes well.

Congratulations all. And well done.

Confounded!

Damn cranial deformation. I can't use geometric morphometrics to analyze whether cranial robusticity diminished in populations that switched from hunting and gathering to agriculture if the agricultural populations engaged in the cultural practice of artificial, intentional cranial deformation. Look at these folks. They're all adults...

The crania are all from a Central Illinois prehistoric agricultural population. In the last picture, the lighter colored cranium on the right is not intentionally deformed, and provides a good comparison. Clearly, I can't use the posterior cranium data from the deformed individuals. The problem is, I might not be able to use mid-cranial data either. I'm not sure exactly how far forward on the cranium intentional posterior deformation has an effect. I suspect far enough that it could raise and widen the posterior aspect of the frontal bone, where I take several landmarks. Where else? Temporals? Probably. Maxillary? At least where they articulate with the temporals.

Cranial deformation could even affect the shape of the mandible: it could, for example, change the shape of the condyles, change overall shape by altering the angle of muscle attachments, or push the ramus (posterior portion of the mandible) farther forward.

Cranial deformation isn't present on all individuals in this Central Illinois population. But even that presents something of a problem. With the naked eye, it's not easy to tell the difference between an individual with a naturally broad, round cranium side-to-side (brachicephaly) and an individual with cranial deformation.

Like I said, not everyone in this population has artificial deformation, so this is not a total disaster. But it is very annoying.

Background reading:

http://www.clas.ufl.edu/users/nparr/index_files/Page398.htm

Blues and BBQ

I managed to keep a fairly healthy diet for the first three weeks of my research trip. Not tempeh and quinoa salad healthy, but reasonably healthy for traveling on a budget, shopping at big chain super markets, and having only a refrigerator and microwave to keep and prepare meals. This past week I got lazy. I didn't feel like getting up in the morning to make another whole roast turkey breast sandwich for lunch. I definitely didn't feel like washing any more salad in my sink for dinner at night. So I went to KFC, picked up a 12-piece dinner, and survived on that for about three days.

After having the Truckdriver's Special breakfast -- french toast, eggs, hash browns, and sausage -- at Bill Evans Family Restaurant Saturday morning, enough was enough. I needed healthy fare. Again, I'm not talking about a vegetarian diet, even though it gets harder for me to justify eating meat the more time I spend in communities, like Springfield, where hunting is popular. I don't see much substantive difference between hunting and eating as two justifications for killing an animal. So it's doesn't make much sense to me that I disapprove of one and still engage in the other. On the other hand, I don't fuss too much over the need for moral consistency.

Boy do I ever digress. My point is that after some local sight-seeing Saturday afternoon, I drove to downtown Springfield to find the specialty market and get myself some good eats. Only instead I found this....

...Hot on the heels of the State Fair, Springfield's annual, jam-packed Blues and BBQ Festival! Baby back ribs and pulled pork (sandwiches) everywhere. BBQ specialists came from as far as Texas and Wyoming to sell their stuff. My healthier diet is postponed for a few days, until I finish the full-rack of ribs I've got broken up into sections in my mini-fridge. I did, however, avoid all fried foods and purchase a couple of side dishes that could at least pretend to be vegetables (baked beans and cole slaw).

Vanity in the Heartland

Almost from the moment I arrived in Springfield, I was struck by the seemingly high percentage of cars sporting vanity license plates. It could have been sampling error at first, just a random encounter with multiple vanity plate cars driving side by side in a two-lane or parked next to one another. But it's not sampling error. People in Springfield purchase vanity plates.

I took all of the following photos in a 24-hour span. I wasn't looking for vanity plates. They're everywhere.

SNOMEN 8 (left, middle-ground), FINN 87, FLAT 367

FITTS 9 and 1 HETON

MISSION and PKAY 92

A 6-bagger! LM, MINNI G, UFO 9, SANTAR 4, JOE 24, and OHHH 7 (continuous row, multiple photos)

It's gotten to the point where I look for vanity meanings on regular old humble plates most likely coded by the State ... "H2O 6458"? This is an excellent use of my free time.

I asked a graduate student who works part time at the Museum about the Springfield vanity plate phenomenon. She surmised that people get them because cars in Springfield all look pretty much the same; individualized plates make it easier to find one's auto in the parking lot. This is a classicly "emic" explanation, if you ask me. Of the 13 cars in the photos above, no two are the same make/model. Further, in any given State, all license plates are unique, regardless of whether their individuality is the result of State assignment or car-owner choice. This is a ready-to-wear dissertation topic for a socio-cultural anthropologist, no? Maybe if my cranial data is a bust, I'll switch wings.

Can you say this on public television?

As I write, Illinois TV station WGN Sports is airing the Yankees-White Sox game, which the Yanks are dominating 9-0. One of the White Sox announcers just said, "The Yankees lineup has a lot of hitters who know how to ride a pitcher hard and put him away wet."

Isn't this expression a sexual allusion, albeit one with great color? I always thought so. Maybe not. Maybe it has something to do with livestock. Anyone?

And yes, I'm supposed to be out touring Abe Lincoln historical sites, but I got stuck trying to decide whether or not to shave my beard. You know, important stuff.

Oh, and the same announcer just referred to a hard swing and miss by Nick Swisher as "big head no cattle." Maybe that says something about the earlier statement in question.

Land of Lincoln Tour Truncated

My plan for this weekend was to visit a few of the Abraham Lincoln historical sites in and around Springfield. My tourism meta-plan is to avoid elitist smirking at unsophisticated tourist offerings. So, I will skip the Abraham Lincoln Presidential Library and Museum.

But I can still engage in a little elitist smirking at descriptions of tourist offerings. An extended description of the Lincoln Museum in the Capital City Visitor, a local tourist guide, includes the following:

-"Professional actors read Lincoln's words. One highlight: a simulated television director's studio where news stories and commericals for Lincoln's 1860 presidential campaign are continuously played on video monitors as though the election were being held in modern times." Wouldn't it be infinitely more interesting to be given a sense of how politicians waged election campaigns in the nineteenth century?

-"Part two of 'The Journey' beings in a replica of the White House's Blue Room, where Mary Todd Lincoln appears to extend her arms in welcome." (While actually wishing all these strangers would stop visiting)

-"In ... a 17-minute layered-projection show, 'Lincoln's Eyes,' ... the seats tremble when cannons are 'fired' into the audience, and other special effects add dimension to the story."

Here's something I'd been wondering about: Lincoln worked as a lawyer and was elected to the Senate while living in Springfield, but he was born in Kentucky, grew up in Indiana, and earned his legacy while living in Washington, D.C. So how exactly did Springfield become Lincoln's historical center of gravity? By arm-twisting and gall, it turns out. The Capitol City Visitor explains: "Within hours of Lincoln's death, the Springfield City Council had passed a special resolution seeking to secure the return of the city's favorite son. During the Washington, D.C. funeral, about 400 people from Illinois attended a special meeting in the White House's East Room to lobby for the body... Mary [Todd Lincoln] initially resisted. Her first choice was Chicago, followed by Washington."

I'm off to Lincoln's Tomb.

Woke up this morning, . . .

. . . put Neosporin on my toothbrush. Temporary brush replacement: q-tips.

Little notes

Accomodations: I switched hotels yesterday, moving myself from the Red Roof Inn to the Day's Inn. The price is the same, but several factors so far make the hassle of packing and unpacking myself one extra time worth the trouble: (1) when I return to my hotel room at the end of the day, I no longer need time to get used to the smell, (2) so far I have found zero pillows in my Day's Inn hotel room with a golf ball-size blood stain, which is one less than the number of such pillows in my room at the Red Roof, and (3) I can be anywhere in this city and easily find my way home now that I live in the shadow of Springfield's giant cloud-making machines.

Postscript on Republican Day at the Illinois State Fair (at best): I suggested it a few days ago, but I didn't actually believe that Republican Day drove down attendance at the Illinois State Fair. However, it may have. It turns out that Republicans do not hold a single statewide office in Illinois, and whathisname, the head of the Illinois Republican whatsitcalled Committee, used the occassion of Republican Day at the Fair to resign his chairmanship.