Birds Don't Miss a Beat
TUESDAY May 12, 2009 -- Birds can tap their feet, sway their bodies and bob their heads in time with a musical beat, say two new studies that suggest the ability to feel the rhythm may be linked to another shared trait between humans and birds -- vocal training and mimicry.
"For a long time, people have thought that the ability to move to a beat was unique to humans," Adena Schachner of Harvard University, leader of the one of the studies, said in a Cell Press news release.
"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."
In their study, Schachner and colleagues reviewed more than 1,000 videos of dancing animals and determined that only vocal mimics -- including 14 parrot species and one species of elephant -- showed evidence of truly being able to move their bodies in rhythm with music.
In the other study, Aniruddh Patel, of the Neurosciences Institute in San Diego, and colleagues found that a cockatoo adjusted the tempo of his dancing to stay synchronized to the beat of music as it was sped up or slowed down.
The findings of these studies support the theory that being able to move in time to a musical beat relies on the neural circuitry for complex vocal learning, which requires a strong connection between auditory and motor circuits in the brain.
The research may also offer new insight into why humans make and enjoy music, which is regarded as an evolutionary puzzle.
"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," Schachner and colleagues wrote.
"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," they added.
The studies were published online in the journal Current Biology.
For more on the unique abilities of some bird species, visit PBS.
Posted: May 2009
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