Humans dance. And we love to talk. If Aniruddh D. Patel, a neuroscientist at Tufts university, is right, there is a deep link between dancing and speech.
Humans are the only primate who can dance. Even our nearest relatives — monkeys, chimps, bonobos — can't manage to synchronize their movements to a beat, something that we do spontaneously and without effort.
Other nonhumans do this surprisingly well. Patel's jaw hit the floor when he viewed this You-Tube video of Snowbell, the dancing cockatoo, back in 2008:
And then there is Frostie the parrot. Frostie, in my opinion, is an even better dancer than Snowbell. He's more expressive and less compulsive:
[Side note: this is a field where, it seems, the Internet, and YouTube in particular, has played an important role in gathering and collecting data!]
What humans and birds have in common, Patel noticed, is that they are vocal learners, that is, they use what they hear to modify the sounds they make. They (or rather we) are adapted not only to do, and not only to perceive, but to organize what we do in relation to what we perceive. Birds learn to sing and we learn to talk. And we both start out babbling, that is, making (and hearing ourselves make) practice sounds. (There was a nice New York Times article about new work in this area a couple of weeks ago.) Dancing, it seems, comes along for free.
A testable hypothesis is a beautiful thing. Patel's hypothesis makes clear and testable predictions. If the vocal learning / movement synchronization hypothesis is right, then one would expect, other things equal, that non-vocal learners won't be able to sync to a beat, and, in the other direction, that vocal learners will be able to do this.
A recent challenge has been posed by findings from a team down in Santa Cruz. (This caught the attention of NPR's Two-Way blog.) The Santa Cruz team trained a California sea lion, Ronan, to sync to a beat. Indeed, they taught him to move to Snowbell's favorite song Everybody by the Backstreet Boys:
Ronan is a challenge to Patel's thesis because it has been widely assumed that sea lions, in contrast to their seal cousins, and humans and birds, are not vocal learners.
But maybe this isn't so. Patel has remarked, in email correspondence with me, that the jury is still out. True, there's no evidence that sea lions are vocal learners, but nor is there solid evidence that they are not. This is an area where we need more science.
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