Beauty and the teeth: perception of tooth color and its influence on the overall judgment of facial attractiveness.

“This study investigated the influence of changes in tooth color on judgments of facial attractiveness. Standardized photographs were presented, and teeth were digitally manipulated (main categories: original, whitened, colored; filler category: impaired). Participants were instructed to evaluate the faces for attractiveness.Additionally, they were asked to name facial features they found either positive or negative with regard to attractiveness. Whitened teeth were mentioned more often in a positive way but did not improve participants’ assessment of attractiveness. A colored tooth did not attract attention, and the attractiveness judgment did not worsen. Tooth color is thus not necessarily perceived and does not have a major impact on facial attractiveness.”

Photo: flickr/david_shankbone

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Here’s an excerpt from my third post at the Techonomy blog–which is on how technology and humanity are “coproduced.” You can read the full post here.

At the official opening plenary session of Techonomy, Kevin Kelly–a co-founder of Wired, and author of the forthcoming book What Technology Wants–made what I considered a pretty profound remark. “The first animal we domesticated was humans,” Kelly said. He went on to describe how we “physically changed ourselves through agriculture, through cooking…we’re both masters of technology and also the children of technology.”

Kelly sounded, in this statement, as though he’d read a book that I recently recommended and blogged about, and whose author I interviewed for BBC 2’s “The Culture Show”: Harvard anthropologist Richard Wrangham’s Catching Fire: How Cooking Made Us Human. It’s hard to think of a better example than cooking if you want to show how human beings and technology are “co-produced,” which I take to be Kelly’s argument.

In Wrangham’s account, our ancestors discovered fire and cooking at some hard-to-fix point in the past—but farther back than most scientists had previously assumed. At this point, the power of this innovation then dramatically drove human evolution.

Cooking food was a game changer….READ ON.

In my review of Replenishing the Earth: The Settler Revolution and the Rise of the Angloworld, 1783-1939 I left one aspect of James Belich’s thesis out of my list of criticisms because it wasn’t relevant to most of the argument. He seems to reject, mostly based on incredulity, the idea that there were massive population collapses in the New World when the natives encountered diseases incubated on the World Island (I say “World Island” because it wasn’t only Eurasian diseases, African slaves brought their own suite of lethal ailments which “cleared out” Amerindians from many lowland zones). He points out, correctly, that the Black Death in Europe is estimated to have resulted in a decrease of only ~1/3 from the total population. How then could it be plausible that there may have been population contractions on the order of a magnitude (i.e., the post-collapse population being only ~10% of the pre-collapse population). The skepticism of extreme population decline on the part of indigenes dovetails with the author’s focus on the particular explosiveness of Anglo natural increase, as well as migratory bursts. Heightening the “contrast effect” at the heart of his central thesis.

I think the author’s incredulity only makes sense in light of biological naivete. To a first approximation moderns tend to assume that all populations are interchangeable in our models. Like the economist ignoring individual differences and fixating on H. economicus for analytical purposes this has some utility, but it does miss much of the picture. The Black Death was only one of many epidemics which swept over Europe, so one can presume that European populations were already somewhat robust in the face of a new strain of infectious disease. The revisionist scholarship, which posits mass population collapse, is thoroughly reviewed in Charles C. Mann’s 1491: New Revelations of the Americas Before Columbus. But even today biological differences matter when it comes to disease, for example in relation to swine flu fatalities.

One of the implicit aspects of Belich’s skepticism is that population crash models in the New World are rooted in inferences, not concrete censuses. But I recently stumbled onto a “test case” for contact between Europeans and indigenous people where we have some good data sets, Tahiti.

The initial data point of ~50,000 in 1767 is a low boundary estimate. But the subsequent data points are more concrete, from missionary surveys, or censuses. Even excluding the estimate the pre-contact population of Tahiti island seems to have dropped by one half in a two generation period. This is greater than the average decrease of the Black Death in Europe.

I think the reason for these massive population collapses when isolated groups meet more cosmopolitan ones is simple: they compress many generations of natural selection and immunity acquisition into just a few. In the historical record we know that the 2nd century A.D. witnessed the outbreak of plagues in the Roman Empire, and the subsequent decline and fall was concomitant with the endemic status of malaria in the Italian lowlands. The great Plague of Justinian in the late 6th century has been fingered as the causal factor behind the rise of Islam, the replacement of Celtic Britons by Anglo-Saxons, and the end of the Classical World more generally. Populations isolated from the grinding pathologies of Malthusian agricultural interlude just experienced it in all its glorious misery in a very short burst.

Source: Urbanization in French Polynesia, RC Schmitt, 1962