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Creationists all thumbs over digits research

by Rowan Hooper

It’s back to basics this month, with a look at evolution, science and religion.

Last week I spent a fascinating morning at the Oxford home of the evolutionary biologist Richard Dawkins, who has just published the first volume of his memoirs. I was there to talk to him about his life and work. Although 11 of his 12 books have been about evolution, he is now well known for his attacks on religion and religious explanations of the world — and much of our chat was about that.

On the train back to London I came across a new paper by Atsushi Iriki, a Japanese neurobiologist based at the RIKEN Brain Science Institute in Saitama Prefecture whose work I’ve followed with interest for years. His new findings offer an answer to a long-debated question regarding human evolution. Then — and here’s the point of my name-dropping reference to Dawkins — I saw that Iriki’s work had been appropriated and twisted by a website offering biblical explanations for the world.

The funny thing is, amid the religious waffle there was an interesting point.

Iriki’s new work concerns the commonly held belief that when our ancestors started standing on two feet, this freed the hands to do other things — hence our ability to use tools and manipulate objects with our fingers evolved after we walked upright. However, this study suggests it was the other way round.

Iriki, with Gen Suwa, an anthropologist at the University of Tokyo Museum, and colleagues, used comparisons between humans and Japanese macaques — best known for their habit of taking baths in natural hot springs — to shed light on how our hands evolved.

One thing Dawkins mentioned during our conversation was the shocking number of people who in polls claim not only to disbelieve the facts of evolution, but to also believe the world is only 12,000 years old. These so-called “young Earth creationists” take the Bible’s contents as literal truth.

One such person, named Elizabeth Mitchell, wrote a nonexplanation of Iriki’s work on a website named Answers in Genesis. “Humans,” she said, “created the same day as monkeys and apes about 6,000 years ago according to the Bible, did not have to evolve the ability to do or be anything, but were already fully human — physically, mentally and spiritually — being uniquely created in the image of God (Genesis 1:26-27).”

It almost goes without saying, but in reality multiple strands of evidence show that Earth is about 4.5 billion years old, and that life arose some 2.5 billion years ago. Monkeys, incidentally, first evolved around 40 million years ago — probably in Asia. And modern humans — like you and me and Dawkins and Mitchell — evolved very recently, about 250,000 years ago.

After quoting extensively from Iriki’s paper, Mitchell concluded: “What the scientists in Tokyo have demonstrated is that monkeys and chimps have differences in their hand and foot shapes, but both are well-designed for their lifestyles.” She added: “This is exactly what we would expect from the Intelligent Creator we share.”

Now, you may think it is better just to ignore such websites — but Answers in Genesis is an international operation with an annual budget of $13.5 million, according to Wikipedia. So it’s worth taking a moment to show how completely it twisted what “scientists in Tokyo” have done.

Iriki’s team used functional magnetic resonance imaging (fMRI) in humans, and electrical recording from monkeys, to locate the brain areas responsible for touch awareness in individual fingers and toes.

First, they confirmed previous findings that each digit in the hands and feet of both monkeys and humans has its own mini-region of neurons in the brain. Then the team went on to find evidence suggesting that monkeys’ toes are combined into a single “map” region in the brain, as are humans’ toes — though the big toes of humans have their own map, whereas monkeys’ big toes do not.

Taken together, this suggests that the ability to dexterously control individual fingers evolved well before humans evolved, as monkeys have individual neural map regions for each digit. In other words, monkeys had the potential to perform tasks requiring manual dexterity.

This skill improved as humans evolved, gaining finer finger control and big toes specialized for walking on two legs — which is why people who lose a big toe have trouble learning to walk again.

Iriki says the new work — published in Philosophical Transactions of the Royal Society B, DOI: 10.1098/rstb.2012.0417 — suggests, contrary to received wisdom, that our dextrous hands did not evolve as a consequence of our standing on two feet.

Mitchell, meanwhile, criticizes scientists because their world view “rejects the eyewitness account of the Creator God of the Bible and presumes evolution had to have happened.”

Putting aside the it-would-be-funny-if-it-weren’t-so-sad claim that the Bible is an eyewitness account of creation, I think she has a kind of point here. It is about the presumption of facts — what Iriki’s team refers to as “received wisdom.” As his work shows, it’s always good to question received wisdom, even that derived from scientific observations — let alone that derived from texts some regard as holy.

Rowan Hooper (@rowhoop on Twitter) is the News Editor of New Scientist magazine. The second volume of Natural Selections columns translated into Japanese is published by Shinchosha at ¥1,500. The title is “Hito wa Ima mo Shinka Shiteru (The Evolving Human).”