January 26, 2006

Are our frontal lobes bigger than in late Medieval times?

The BBC reports:

Researchers have found that the shape of the human skull has changed significantly over the past 650 years. Modern people possess less prominent features but higher foreheads than our medieval ancestors.

Writing in the British Dental Journal, the team took careful measurements of groups of skulls spanning across 30 generations. The scientists said the differences between past and present skull shapes were "striking"...

They looked at 30 skulls dating from the mid-14th Century. They had come from the unlucky victims of the plague. The skulls had been excavated from plague pits in the 1980s in London.

Another 54 skulls examined by the team were recovered from the wreck of the Mary Rose which sank off the south coast of England in 1545.

All the skulls were compared with 31 recent orthodontic records from the School of Dentistry in Birmingham.

The two principal differences discovered were that our ancestors had more prominent features, but their cranial vault - the distance measured from the eyes to the top of the skull - was smaller. Dr Peter Rock, lead author of the study and director of orthodontistry at Birmingham University, told the BBC News website: "The astonishing finding is the increased cranial vault heights.

"The increase is very considerable. For example, the vault height of the plague skulls were 80mm, and the modern ones were 95mm - that's in the order of 20% bigger, which is really rather a lot."

He suggests that the increase in size may be due to an increase in mental capacity over the ages.

Is this true? Did foreheads, and presumably frontal lobes, get bigger over a few dozen generations in England, where there was very little ethnic change from 1066 to 1945?

I have the nagging feeling that some scholar did a more complete study than this of this question back in, say, 1930, when skull measurements were the bread and butter of anthropology, but the answer got buried by the triumph of the Boasian cultural anthropologists.

Along those lines, the latest NYT Magazine ran a good articled called "The Animal Self" by Charles Siebert on the belated rediscovery by scientists of the fact, which is utterly obvious to anyone who has owned more than one pet of the same species, that animals have varying personalities and feel emotions that are often similar to ours:

Not so very long ago, concepts like animal sentience, emotion and personality were not merely the stuff of anecdotes told by farmers and pet owners; they were wholly embraced by the scientific community as well. In the late 19th century, animal emotion and behavior were integral aspects of the newly emerging science of human psychology. Charles Darwin devoted much of his time after the publication of "The Origin of Species" to researching "The Expression of the Emotions in Man and Animals," published in 1872. Although that era's cross-species conjecturing and comparing was often naïve or intuitive, the impulse behind it went on to inform human psychological study well into the 20th century. Beginning with the appearance in 1908 of more sober, scientifically sound works like John Lubbocks's "On the Senses, Instincts, and Intelligence of Animals With Special Reference to the Insects" or Edward L. Thorndike's "Animal Intelligence," animal studies figured prominently in standard human psychology textbooks well into the 1940's. And then, steadily, the animals began to disappear...

The banishment of our fellow beasts from psychological literature can be blamed by and large on that branch of psychology known as behaviorism. The field's major proponents, eminent psychologists like B.F. Skinner, stressed the inherent inscrutability of mental states and perceptions to anyone but the person experiencing them. And even though the behaviorists were themselves major proponents of the use of animals in behavioral research, they sought to rein in subjective verbal descriptions of the animals' mental states, as well as the sorts of experiments that relied on such necessarily vague data. If the human mind was, as Skinner famously referred to it, "a black box," then surely the minds of animals were even further beyond our ken...

Now, however, the pendulum has begun to swing back in that direction, and it is a shift that has been impelled, somewhat surprisingly, by hard science. Advances in fields like genetics and molecular and evolutionary biology have lent to the study of psychology something that it really didn't have when behaviorism first came to the fore: a better understanding of the biological and bioevolutionary underpinnings of behavior.

On the whole, science is less driven by arbitrary and often stupid fads than is, say, architecture, but it's hardly immune. The marginalization -- in fact, the demonization -- of physical anthropology and biometrics by the cultural anthropologists after WWII was definitely one of those stupid fads, and harsher terms like "disinformation campaign" might be more appropriate.

My published articles are archived at iSteve.com -- Steve Sailer

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