[tt] Boston Globe: Eggheads: How bird brains are shaking up science

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Eggheads: How bird brains are shaking up science
http://www.boston.com/news/globe/ideas/articles/2007/09/16/eggheads
[Linked by Arts & Letters Daily.]
7.9.16
By Jonah Lehrer

THE NEW CALEDONIAN crow is surprisingly smart about its food. Its
favorite insects live in tiny crevices that are too narrow for its
beak. So the crow takes a barbed leaf and, using its beak and claws,
fashions a primitive hook. It then lowers the hook down into the
cracks, almost like a man fishing, and draws up a rich meal. Some
scientists even suggest that crows are more sophisticated tool
builders than chimps, since they can transmit their knowledge on to
successive generations and improve the tools over time. These birds
have a culture.

The world lost its most famous bird brain this month: Alex, an
African gray parrot who lived in a Brandeis laboratory and possessed
a vocabulary of nearly 150 words. Yet as remarkable as Alex was - he
could identify colors and shapes - he was not alone. The songs of
starlings display a sophisticated grammar once thought the sole
domain of human thinking. A nutcracker can remember the precise
location of hundreds of different food storage spots. And crows in
Japan have learned how to get people to crack walnuts for them: They
drop them near busy intersections, then retrieve the smashed nuts
when the traffic light turns red.

These feats are part of a growing recognition of the genius of
birds. Scientists are now studying various birds to explore
everything from spatial memory to the grammatical structure of human
language. This research is helping to reveal the secrets of the
human brain. But it is also overturning the conventional
evolutionary story of intelligence, in which all paths lead to the
creation of the human cortex. The tree of life, scientists are
discovering, has numerous branches of brilliance.

"It used to be that people would only talk about intelligence in
terms of primates," says Nicola Clayton, a professor of comparative
psychology at the University of Cambridge. "But now I think that
birds have achieved a sort of honorary ape status, just with a few
feathers attached."

The intelligence of birds, which sit far from man on the
evolutionary tree, has also forced a reappraisal of where
intelligence comes from. Scientists once assumed that intelligence
evolved out of physical need - animals got smart in order to exploit
natural resources. But the brainpower of birds suggests that
intelligence is actually a byproduct of complex social interactions.
Living in a group requires an animal to juggle lots of information
about its peers. So it's not a coincidence that the smartest
creatures are also the most social.

Crows, for example, live in strikingly human social structures. They
are devoted to their families, but can assemble in much larger
flocks if resources are sufficient. African grays follow a similar
pattern, roosting at night with hundreds of other birds, but
foraging during the day with an intimate group of kin. These
intricate social structures mean that many birds are subject to the
same social challenges as primates. It is these challenges, the
research suggests, that make them so smart.

. . .

For most of the 20th century, "bird brain" has been used as an
insult. Noting the stark structural differences between human and
bird brains, anatomists concluded that birds are essentially flying
reptiles. Their minds were too tiny for thought. But in recent
years, scientists have discovered that the bird brain doesn't
deserve its reputation.

In 2005, Alex wowed many scientists when he began spontaneously
using the word "none" to represent a rudimentary conception of zero.
He also enjoyed inventing new words for things: he referred to
almonds as "cork nuts," since the texture of the nut resembles that
of a wine cork. An apple was a "banerry," a combination of two of
his favorite other fruits, bananas and cherries.

"All of these cognitive abilities weren't supposed to be possible in
birds," says Dr. Irene Pepperberg, the scientist who worked with
Alex. "But Alex showed us just what a bird brain is capable of."

The first aspect of bird intelligence scientists studied was
birdsong. Charles Darwin compared the early vocalizations of young
songbirds with the babbling of human infants, noting that both
species went through a period of intense vocal learning. In the
early 1970s, Fernando Nottebohm, a neuroscientist at Rockefeller
University, wanted to understand how certain songbirds managed to
learn new melodies every year. As Nottebohm notes, birds are the
only other species that "attempts vocally to do anything like what
we do." Perhaps, he wondered, the impressive learning abilities of
songbirds could be used to understand aspects of the human mind.

Nottebohm's search for the source of birdsong led him to discover
something entirely unexpected. In order for birds to learn new
songs, they have to generate new brain cells. At the time, this was
a radical idea. Neuroscientists believed that virtually all animal
brains - and certainly the human brain - stopped creating new brain
cells shortly after birth. But Nottebohm showed that up to 1 percent
of the neurons in the song center of their brains were created anew,
every day.

Other researchers, including Elizabeth Gould of Princeton, later
extended Nottebohm's data to a long list of other species, including
great apes and humans. The research that began with a canary's
melody is now being used to help develop potential treatments for a
wide range of human illnesses, from Parkinson's disease to spinal
cord injuries.

"These little birds overturned one of the big dogmas of
neuroscience," Nottebohm says.

Timothy Gentner, a neuroscientist at the University of California at
San Diego, is using European starlings to overturn another deeply
held scientific idea: that only humans are capable of learning
complex grammatical patterns. According to research published last
year in the scientific journal Nature, songbirds can be trained to
distinguish a system of "warbles" and "rattles" that share the same
underlying structure as a human sentence. Some saw the surprising
results as a refutation of the position, advanced by scientists such
as Noam Chomsky, that the human mind is uniquely designed to deal
with such grammar.

While Chomsky dismissed the study as having "nothing to do with
language," Gentner believes that starlings reveal "the deep
biological roots of human language."

The grammatical skills of male songbirds are driven by their
elaborate social interactions with females. "The goal of a singing
starling is to find a mate," Gentner says. "They make their songs
more and more complex in order to impress the females. The ability
to learn these grammatical patterns grew out of that. It's like a
cognitive version of the peacock's tail."

Similar social pressures have driven other aspects of avian
intelligence. Many birds store vast quantities of food in various
hiding spots, which they later recover when food is scarce. (Clark's
nutcracker, for example, is able to store more than 30,000 seeds in
hundreds of hiding spots over a 12-square-mile area. No primate can
match this.) The problem with stored food, however, is that it's
easy to steal. As a result, many birds regularly re-hide their food
if they suspect other birds have observed their original spots.

This suspicious behavior depends on a very impressive feat of social
intelligence, which had never before been observed outside primates.
Nicola Clayton and Nathan Emery, another researcher at the
University of Cambridge, showed in 2001 that only western scrub jays
that had previously stolen food from other birds would always
re-hide their food. Jays that had never stolen before didn't worry
about being stolen from.

"These birds are projecting their experience of being a thief onto
other birds," Clayton says. "They are thinking 'Well, I've stolen
food, so this guy might too.' It's a form of mental simulation."

Such cognitive skills require a big brain. In fact, the brains of
crows and some parrots are roughly the same size as the chimpanzee
brain relative to body size. These avian brains are also enlarged in
areas that approximate the primate prefrontal cortex, a region that
underwent a great expansion during human evolution.

But these broad similarities are the exception to the rule. For the
most part, the clustered anatomy of the bird brain is organized very
differently from the layered anatomy of the primate brain. For
scientists, that's part of what makes the bird brain so fascinating.
It's a different anatomical solution to the same evolutionary
problem of how to live as a social species.

This suggests that some rarefied aspects of human intelligence, such
as tool use and the ability to imagine what other minds are
thinking, have actually evolved independently in birds. In the
history of life, the primate brain and bird brain diverged hundreds
of millions of years ago; birds are direct descendants of dinosaurs.
Yet the unfolding research into avian intelligence shows that humans
have much to learn from birds. Among the lessons: that we, like
birds, are smart because we have to deal with each other.

Jonah Lehrer is an editor at large at Seed magazine. His first book,
"Proust Was a Neuroscientist," will be published in November.