Mind-Reading Hat Could Prevent Brain Farts

Big Brains Not Always Better

Michael Schirber, LiveScience Staff Writer, 02/19/2005

WASHINGTON D.C. - Nearly three million years ago, our ancestors had brains about as big as modern chimps. Since then the brain that would become human grew steadily, tripling in size. But this extra cranium capacity may not have resulted in smarter hominids.

As far as tool-making is concerned, there is little evidence of improvement over much of the period that the brain was growing.

"Archaeology has found that brain size grew gradually, but cleverness took steps," said William Calvin, a neurobiologist from the University of Washington.

The most dramatic of these steps is referred to by some as the Mind's Big Bang. It occurred between 50,000 and 70,000 years ago. This burst of creativity resulted in bone tools, including sewing needles and throwing sticks. There was also a flourishing of portable art, like necklaces and pendants, as well as cave paintings.

"There was nothing like this before," Calvin said here Friday at the annual meeting of the American Association for the Advancement of Science meeting in Washington, D.C.

It is hard to explain the Mind's Big Bang with a jump in skull size, seeing as Homo sapiens with modern-sized brains had already been around for 100,000 years or more before the tool and art revolution occurred.

"The big brain was perhaps necessary for the creative explosion at 70,000 years ago, but it sure wasn't sufficient by itself," Calvin said.

Subtle advancements

So what was a larger brain good for? What was the evolutionary advantage that propelled our family tree to make more room between the ears?

Calvin postulates that a big brain may have made our ancestors better hunters by improving their throwing accuracy. Or perhaps it allowed for the development of a rudimentary language of three-word sentences.

The social psychologist Robin Dunbar has even suggested that the higher memory capacity in a bigger brain could have helped early hominids identify freeloaders who were not pulling their weight for the community.

But none of these subtle advances, according to Calvin, led to the emergence of behaviorally modern humans.

"If you can't speak sentences of more than 2-3 words at a time without them all blending together like a summer drink, you likely cannot think complicated thoughts either," he said.

Increasing sentence length or doing multi-stage planning requires an understanding of structure. Moreover, it is structural creativity that led to advances in tools and art.

Spread of innovation

This structure may have developed in early human language and thought through trial and error.

"We invent new levels on the fly," Calvin said.

A lot of this invention might be nonsensical, but occasionally an innovative adult might have tried out a new word or syntax, and a child heard it and began incorporating it into his or her language.

"Then long-sentence language can spread like a contagious disease, as more kids hear structured sentences and grow up to become super adults," Calvin explained.

The incorporation of more and more complexity is attributable to a combination of culture and genes.

"Behavior invents, and then little genetic changes come along that improve it," Calvin said.

He wonders if we might be headed into a second big bang of the mind. With "better-informed education" based on empirical methods, Calvin postulated that we might see a creative flourishing in the coming century, comparable to the advances made in medicine of the past century.

轉貼自：

http://www.livescience.com/health/050219_big_brains.html

Are Big Brains Smarter?

Jeanna Bryner, LiveScience Staff Writer, LiveScience.com 

If this were true, then perhaps big-headed people wouldn't be so pea-brained.

This question is mired in many unknowns. For one, scientists still debate over the definition of intelligence. For any IQ definition, how do you measure it? Further, do differences in IQ show up in daily life? And finally, does more brain tissue or a heftier brain equate with higher IQ?

One thing scientists do agree on: A big brain alone doesn't equate with smarts. If it did, elephants and sperm whales would win all the spelling bees. Rather, scientists look at brain mass relative to body mass in order to make any speculation about a creature's cognitive abilities.

So while an elephant noggin, at 10.5 pounds (4,780 grams), could squash a human think box in a purely physical battle of brains, you and I take the cake in a war of wits. Our brains, which weigh an average of 2.7 pounds (1,200 grams), account for about 2 percent of body weight, compared with an elephant's under one-tenth of a percent.

Studies have shown that across species relatively large brains "do seem to provide some complex cognitive skills, such as innovative solutions to ecological problems, more efficient resource mapping and food acquisition, and more complex social strategies (such as deception)," said Nancy Barrickman, a graduate student in Duke University's Department of Biological Anthropology and Anatomy.

Differences in brain size within a species, such as humans, are relatively small, making it difficult to tease out the effects of brain size and the effects of other factors. For instance, the difference in intelligence between an organism with, say, a brain that's 1,100 grams and one that's 1,400 grams (which could be found in humans) is confounded by other variables, including differences in density of neurons, other structural brain differences and socio-cultural factors.

And the debate continues ...

Brain size has nothing to do with scores on standardized intelligence tests, according to a brain-scan study of young children.

Michael McDaniel, an industrial and organizational psychologist at Virginia Commonwealth University, has claimed that bigger brains do make for smarter people. Many researchers, however, disagree with McDaniel's conclusion. His research, published in 2005 in the journal Intelligence, suggested that across all age and sex groups, brain volume is linked to intelligence.

Men are smarter than women, according to research published in 2006, which the study researchers say could be due to men having relatively larger brains, a difference of about 0.2 pounds (100 grams). Another scientist put forth several socio-cultural factors that would make the men-smarter results null.

Average brain weights for primates (not relative to body size):

·           Chimpanzee (Pan troglodytes) - 0.77 pounds (350 grams)

·           Mountain gorilla (Gorilla gorilla beringei) - 0.95 pounds (430 grams)

·           Mouse lemur (Microcebus murinus) - 0.004 pounds (2 grams)

If brain size had anything to do with innovation and creativity, some scientists expected to see a link between the so-called Mind's Big Bang (the emergence of bone tools and cave paintings that occurred between 50,000 and 70,000 years ago) and the emergence of modern-size human brains. Not the case.

·           Big Brains Mean Longer Life 

·           Top 10 Mysteries of the Mind 

·           Sex, IQ and ET: How We Got Big Brains 

轉貼自：

http://news.yahoo.com/s/livescience/20080418/sc_livescience/arebigbrainssmarter;_ylt=Ar88px4YFWEFHV0xYcwZw3gbr7sF