Shall we Dance?
(January 20th, 2016) Elephants do it, chimpanzees do it, and yes, even humans like to shake a leg from time-to-time. What started the evolution of dance? Swaying to a salsa rhythm, our writer, Alejandrolvido, tries to find the answer.
I’m in the middle of the dance floor. As I try to move to the rhythm of the loud music, I step on her foot again. Why am I such a poor dancer? I turn to Elizabeth and groan in her ear: why is dancing so complicated? “I guess that’s another unsolved mystery… or maybe somebody already scanned the brain of dancing humans and got some ideas!” she replies.
I remember the recent essay by Laland et al. Their argument sounded good to me: Dance is a by-product of the neuronal networks that were originally dedicated to imitation. When dancing humans were analysed with positron emission tomography (PET), their brains showed activity in the regions that are responsible for copycatting, such as the medial superior parietal lobule. I’m still sceptical. A good dancer, like Elizabeth, does more than simple imitation; she embodies one of the challenges of neurobiology, that is, the correspondence problem. Her brain is transforming visual and auditory input into a beautifully-coordinated motor output. But how does her brain match the beat to the sinuous movement of her body?
Suddenly, they play Salsa. “Do you know”, she says as she places her hands on mine, “that the neocortex, which makes up 80% of the brain, is required for dancing?” That might be because it contains mirror neurons, the ones that fire when we imitate somebody. They could help to solve the correspondence problem and transform a catchy beat into feet tapping. Laland et al. would argue that limb control at the cerebellum is also essential for matching the actions of a performer to the music.
“Dance is hard to define,” I admit, trying not to step on her foot again. Musicobiologists prefer to study music entrainment: the capacity of moving synchronously with a musical beat. All human cultures have it, as anyone who has attended the last day of an international scientific conference will confirm.
Our promptness for music entrainment can be described by the “vocal learning and rhythmic synchronization hypothesis”, which is supported, among others, by viral videos of dancing cockatoos in the internet. Good imitators have the neural circuitry for complex motor or vocal learning required to feel the rhythm. Consistently, the Asian elephant, chimpanzees and several birds, like parrots, have shown to appreciate a nice beat. All of them being better motor or vocal imitators than me, as I can judge by the way Elizabeth goes off to get a drink. “Are your feet ok?” I ask and wonder whether the first human to ever dance was simply just trying to imitate something - that we will never know.
Photo: www.publicdomainpictures.net/Kevin Tomes