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Building A Bigger Brain

from the July 13, 2010 eNews issue
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In the mid-1800s, it became popular to measure brains and cranial capacity in order to prove the higher intelligence of certain groups of humanity. Humans had bigger brains than apes. The bigger the brain, the argument went, the greater the intelligence, and those humans with brains closer to the size of apes must be less highly evolved and therefore less intelligent. Of course, the European male scientists doing the studies "proved" that Caucasian brains were the biggest and African brains were the smallest, with Indians and Asians in between. In reality, though, these men only proved how far they would go to distort science to support their own prejudices and preconceived ideas.

In his 1981 book The Mismeasure of Man, Stephen Jay Gould systematically examines the acrobatics that these 19th century scientists went through to prove that whites were smarter than blacks, that men were smarter than women, and that society's undesirables were more ape-like. Gould, an evolutionist himself, shows that even those scientists who prided themselves on their commitment to the data had a tendency to make the data say what they wanted the data to say.

In his introduction, Gould says, "In reanalyzing these classical data sets, I have continually located a priori prejudice, leading scientists to invalid conclusions from adequate data, or distorting the gathering of data itself."

That's a problem. Science is supposed to be the collection of pure data which leads to conclusions that we can all trust. Scientists, though, no matter how impartial they claim or try to be, still bring their personal beliefs and biases to the table. This is certainly true in areas of study open to wide interpretation, but even in studies that appear to be objective, the way a study is set up or the interpretation of its data can be subject to the scientist's often unconscious preconceived ideas.

Bias and Brain-Sizes:
For instance,19th Century physician Samuel George Morton sought to rank the races through brain size. He collected over a thousand skulls during his lifetime, but – likely unconsciously – selected skulls and measured their cranial capacity in a way that supported what he already believed. For instance, he chose the largest Caucasian skulls to measure, but had no problem including the small Inca Peruvians in the Indian category, thus reducing the average brain size of Indians compared to Caucasians.

Paul Broca, the famous professor of clinical surgery after whom the Broca's convolution in the brain is named, considered himself the objective scientist on the issue. He attacked the egalitarians of his day for allowing their hopes for the equality of mankind to cloud their judgment. He collected tremendous amounts of data to demonstrate that white people were more intelligent than "lowly races" and that men were more intelligent than women. When the evidence didn't fit his expectations, though, he found ways to explain it away.

For instance, he willingly corrected for the body sizes of small men when measuring their brain sizes, but did not feel obliged to do so for women. After all, he said, we all know that men are smarter than women. He said, "We might ask if the small size of the female brain depends exclusively upon the small size of her body. But we must not forget that women are, on the average, a little less intelligent than men, a difference which we should not exaggerate but which is, nonetheless, real."

As the old saying goes, "If I hadn't believed it, I wouldn't have seen it."

In fact, there was no consistent differences between the brain sizes of blacks and whites or Asians or Australians or men and women that could not be accounted for by the differences in body size, age, or health.

Brain size doesn't have much to do with intelligence anyway, contrary to what most people think. Even in Broca's day, he noted that certain eminent scientists had unexpectedly small brains, and recent studies have failed to show a correlation between brain size and intelligence.

Brain Size Studies Today:
A University of Minnesota study recently published in the journal Psychological Science demonstrates a link between the size of certain parts of the brain and specific personalities. People with a larger lateral prefrontal cortex are more likely to be conscientious, while extroverted people tended to have a bigger medial orbitofrontal cortex. However, no particular part of the brain appears to be larger in conjunction with intelligence or creativity. The scientists involved also noted that various parts of the brain may grow larger by exercising them through life experiences and are not necessarily genetically predetermined. A wide variety of factors can influence a person's personality, and the brain changes as it grows.

A recent study published July 12th in the journal Neurology concludes that people with larger brains are able to weather Alzheimer's better than people with smaller brains, possibly because there is more "back-up" space to use. However, while genetics may have an influence, nurture does a lot to determine the health of a person's brain. The brain does the majority of its development prior to age six, and children's brains develop better if the kids are actively cared for and have lots of opportunity for their minds to be stimulated. The brains of older people tend to be smaller than those of younger people, and keeping the brain active, exercising, and eating a healthy diet will also discourage the atrophy of the brain as seen in Alzheimer's.

Today, peer-review and lively discussion between scientists help uncover biases and keep scientists honest. Ultimately, whether performed in the 1800s or today, scientific studies are still done by human beings, and with them comes the ever-present "human" element. Especially when controversial issues are the subject of a study, it is important that researchers be aware of their own and others' intellectual baggage. For instance, Donald Johanson and the rest of the world can still see in the australopithecines a distant evolutionary relative, while those without an evolutionary viewpoint would say, "Lucy's just an ape." Geologists who assume the great age of a volcanic eruption will use Potassium-Argon dating to age-date volcanic rocks and, because K-Ar dating doesn't work accurately for recent events, will get an age of millions of years even if the volcanic eruption occurred 4000 years ago.

Christians are not free from guilt in this area, either. The problem cuts both ways. As we pursue scientific investigations, it is vital to be aware of our own biases and presuppositions. The true answer to any investigation is out there, and God is a God of Truth. Our job is to be honest, and do our best to diligently study and find out what it is. (And exercise our brains to ever-healthier sizes in the process.)