Big Brain: The Origin and Future of Human Intelligence
by Gary Lynch and Richard Granger
Summary
Our big brains, our language ability, and our intelligence make us uniquely human.
But barely 10,000 years ago (a mere blip in evolutionary time) human-like creatures called “Boskops” flourished in South Africa. They possessed extraordinary features: forebrains roughly 50% larger than ours, and estimated IQs to match--far surpassing our own. Many of these huge fossil skulls have been discovered over the last century, but most of us have never heard of this scientific marvel.
Prominent neuroscientists Gary Lynch and Richard Granger compare the contents of the Boskop brain and our own brains today, and arrive at startling conclusions about our intelligence and creativity. Connecting cutting-edge theories of genetics, evolution, language, memory, learning, and intelligence….[T]he authors demystify the complexities of our brains in this fascinating and accessible book, and give us tantalizing insights into our humanity--its past, and its future.
Excerpt
ARE BIGGER BRAINS BETTER?
A human brain averages roughly 1350 cubic centimeters in volume, with normal brains easily ranging from 1100 to 1500 cc. From human to human, bigger isn’t necessarily better: some very intelligent and accomplished people have small brains, and vice versa. At two extremes, satirist Jonathan Swift had an apparently giant brain of roughly 1900 cc, while equally noted writer Anatole France reportedly had a brain that barely topped 1000 cc. Geniuses are no
exception. Einstein’s brain reportedly measured an average and undistinguished 1230 cc.
For different members of the same species, a bigger brain may well be unimportant. But between different species, brain size can mean a lot.
Brains, like any other body part, are partly scaled to the overall body size of the animal. Bigger animals tend to have bigger brains, just as they have bigger eyes, feet, and bones. But some animals have features that don’t seem to fit their overall body size: the neck of a giraffe, the teeth of a tiger, the trunk of an elephant. So if we measure the ratio of a body part to the overall body, most will maintain the normal size relations, while some will stand out from that scale.
On that scale, humans have normally-sized eyes, bones, and feet. But compared to other animals of our size,we have excessively huge brains. Our brains are smaller than an elephant’s, but human brains are disproportionate: for our body size they are much larger than those of any other creature. Our nearest relatives are chimpanzees; if you take a chimp and a human of roughly equal body size, the person’s brain, at roughly 1,350 ccs, will outweigh the chimp’s brain by more than three times. For the same body mass, we have the equivalent of more than three of their brains. This is unprecedented; if you chart the relation between brain size and body size, as we will in chapter 11, most animals will stay very close to the predicted ratios; humans will be wildly distant from them. One could argue that our brains are our defining feature, setting us apart from all other creatures in the world.
Indeed, it’s our great brains, and our resulting intelligence, that changed everything in the world. Our vast population, our colonization of every corner of the earth, our remolding of physical features of the planet; all are new phenomena in a mere ten thousand years, after billions of years of life before humans.
What is it in our brains that led to our dominance, and what is it
in Boskops’ bigger brains that didn’t?
Copyright @2008 by Gary Lynch and Richard Granger. Reprinted with permission of Palgrave USA.
Reviews
“[B]ig, explosive ideas by two ingenious brain scientists"—Michael Gazzaniga, author of The Ethical Brain
“[C]hallenges conventional views in a scholarly yet wonderfully accessible manner"—Richard Morris, Director of the Centre for Cognitive and Neural Systems, University of Edinburgh, and President, Federation of European Neuroscience Societies, and Former Chair, Brain Research Association of the United Kingdom
"The brain makes all our hopes, dreams, and fears possible. How did it come to be? Fascinating and provocative”—Joe LeDoux, author of The Emotional Brain
Author's Biography
Gary Lynch is a professor at the University of California, Irvine. He is the author of more than 550 scientific publications that are among the most cited in the field of neuroscience. He is the co-inventor of a novel family of cognition-enhancing drugs called “ampakines”, is co-founder of three technology companies (Cortex Pharmaceuticals (NASDAQ: COR), Synaptics (NASDAQ: SYNA), and Thuris Corporation), has served as advisor to multiple professional entities including the Society for Neuroscience and the Jet Propulsion Laboratory, and has been featured in major television networks, newspapers, and magazines ranging from the Los Angeles Times to Popular Science.
Richard Granger is W.H. Neukom Distinguished Professor of Computational Science and of Psychological and Brain Sciences at Dartmouth. He has been the principal architect of a series of advanced computational systems for military, commercial and medical applications, and co-inventor of FDA-approved devices and drugs. He is a consultant, co-founder, and board member of numerous technology corporations such as Thuris Corporation and Cortex Pharmaceuticals, and government research agencies including the Defense Advanced Research Projects Agency, the National Science Foundation, and the Office of Naval Research. His work has been highlighted in numerous popular press and television features, including recent stories in Forbes, Wired, and on CNN.