April 30, 2009

New Research Shows Birds Can ‘Dance’

Two recently published studies show that some birds, parrots in particular, can "dance" to a musical beat.

The reports, published online on April 30th in Current Biology, reveal that birds can also bob their heads, tap their feet, and sway their bodies along to a musical beat.

Researchers said the findings show that a very basic aspect of the human response to music is shared with other species.

"We've discovered a cockatoo [named Snowball] that dances to the beat of human music," said Aniruddh Patel of The Neurosciences Institute in San Diego, lead author of one of the studies.

"Using a controlled experiment, we've shown that if the music speeds up or slows down across a wide range, he adjusts the tempo of his dancing to stay synchronized to the beat."

One of Snowball's favorite dancing tunes is none other than the Backstreet Boys' "Everybody," Patel said.

In the other reported study, researchers at Harvard University reached similar conclusions that birds can indeed dance to a beat.

This capability was previously believed to be specific to humans, but the Harvard researchers found that only species that can mimic sound seem to be able to keep a beat, implying an evolutionary link between the two capacities.

"For a long time, people have thought that the ability to move to a beat was unique to humans," added Adena Schachner of Harvard University, who led the other study.

"After all, there is no convincing evidence that our closest relatives, chimpanzees and other apes, can keep a beat, and there is similarly no evidence that our pet dogs and cats can line up their actions with a musical beat, in spite of extensive experience with humans. In this work, however, we found that entrainment [to music] is not uniquely human; we find strong evidence for it in birds, specifically in parrots."

Until now, "scientists who studied music and the brain thought that moving to a musical beat might be a uniquely human ability because we don't commonly see other animals moving rhythmically to music," Patel agreed. In fact, as far as they know, birds in the wild don't move in time with sounds, leaving many scientists to think that this ability might be an evolutionary specialization of the human brain for music cognition.

However, the new studies suggest that may not be the case.

Scientists now suspect that the parrot's ability can be traced to another capacity they share with people: vocal learning or mimicry.

Schachner's group searched YouTube for videos of dancing animals. Of more than 1,000 videos that turned up, only those of vocal mimics "“ representing 14 parrot species and one species of elephant "“ showed evidence that they could really get into the groove.

That result is in keeping with the notion, first proposed by Patel, that entrainment to a musical beat relies on the neural circuitry for complex vocal learning, which requires a tight link between auditory and motor circuits in the brain, they said.

"A natural question about these results is whether they generalize to other parrots, or more broadly, to other vocal-learning species," including songbirds, dolphins, elephants, and pinnipeds, a group including walruses and seals, Patel said.

The findings in birds also offer new insight into humans' relationship to music.

"Why humans produce and enjoy music is an evolutionary puzzle," Schachner's team wrote.

"Although many theories have been proposed, little empirical evidence speaks to the issue. In particular, debate continues over the idea that the human music capacity was not selected for directly, but arose as the byproduct of other cognitive mechanisms. By supporting the idea that entrainment emerged as a byproduct of vocal mimicry in avian species, the current findings lend plausibility to the idea that the human entrainment capacity evolved as a byproduct of our capacity for vocal mimicry."


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