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Repeat After Me

What do these groups of animals -- parrots, hummingbirds, songbirds, bats, elephants, cetaceans (whales and dolphins), and possibly some lions -- have in common with us humans? Hint: think what parrots are famously good at.

Right, parroting. These seven animal groups - and no others known so far -- can imitate sounds they've heard. Other creatures may understand the meaning of sounds, but they can't mimic them. A dog knows what "sit" means but can't, well, parrot that sound. A chimp can ape, but not vocally. All they can do is produce sounds they were born with.

03-jarv-jarvis.jpgWhy? The reason, as Erich Jarvis of Duke University and other neurobiologists have found in birds and humans, have evolved a special neural connection that makes this possible. It's a direct link from the forebrain to motor neurons in the brainstem that are responsible for vocalization. It's this link that enables our speech.


Jarvis and colleagues are just beginning to uncover the physical basis of that neural hook-up -- one of many recent advances that are forcing a radical revision in how we think about animal smarts.


Erich Jarvis © NOVA/WGBH Educational Foundation

"What we've been looking for, and I'm pretty sure we're finding now, is the genes responsible for making that direct connection," Jarvis told me on the phone the other day. Jarvis believes that one or more mutations in existing genes brought about this rare trait, possibly independently in all seven lineages known to have the ability. "We're not saying we've found the smoking gun, but we're getting closer to something that makes logical sense," he says.

iStock_000003408599Small[1].jpgA zebra finch, one of the species Jarvis studies in his lab. © iStockphoto/dr_hector

This putative tweak of genetic code has helped enable quite sophisticated behavior in animals that got the mutation-behavior that goes beyond simple parroting and might smack of intelligence. Take the songbirds: Mockingbirds can produce hundreds if not thousands of calls, many of them learned. Chickadees can remember where they buried thousands of seeds. Jays have demonstrated mental time travel. Crows (yes, they're songbirds) can make and use tools.

But aren't chimps a lot smarter than birds? Well, it depends on how you define intelligence, Jarvis says.

For most of the last century, Jarvis told me, biologists thought that the layers in the mammalian cortex -- the distinctive folds covering the tops of our brains -- allow for more complexity than the corresponding ball-like structure in birds and reptiles. "So mammals in general are going to be more intelligent than non-mammals, with a lineage leading up to humans -- that was the idea," Jarvis says.

But he and others are showing that neither folds nor even brain size are necessary for such cognitively complex behavior. What's ultimately important, Jarvis says, is the connectivity of the brain's neural networks.

Intelligence, such research is showing, comes in different forms and flavors, not just the human kind.

User Comments:

Having had parrots for several years, I know how intelligent they are. I know my house cats are as well and often wonder just what they are thinking....

My Goffins Cockatoo used tools all the time. He used the stems from millet sprays to scratch himself in paces he could not reach. I have not witnessed but have heard of other birds doing the same thing. As for talking, he even used speech appropriately. Scolded himself when he did something bad or would say "night night" if he was disturbed while he was asleep. Call me a "Bird Brain" any time. I consider it a compliment!

Hi:

I just wanted to comment that I found your topic interesting from a professional perspective. I work as a speech-language pathologist. My caseload is all children between about 15 months - 3 years old. Imitation is one of the key goals I work to achieve with children presenting with expressive language delays. The colloquial expression I use for it is "getting them noisy." There is a period in normal human language development that most - not all- children go through which involves imitation with increasing frequency as a precursor to independent word usage.

BTW: I'm also a bird lover, and still remember my neurology course section on the hippocampus growth and remarkable spatial memories of food storing birds, like the chickadee. So appreciated the piece from both angles. Thanks!

The margay has also recently been discovered to imitate the sounds of its prey.

http://whyevolutionistrue.wordpress.com/2010/07/11/deceptive-predatory-cats-imitate-monkey-calls/

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