Birds that boogie
[I reckon this one speaks for itself. It is on Nature News. I just hope Snowball can handle the fame.]

YouTube videos of dancing cockatoos are not flukes but the first genuine evidence of animal dancing

When Snowball, a sulphur-crested male cockatoo, was shown last year in a YouTube video apparently moving in time to pop music, he became an internet sensation. But only now has his performance been subjected to scientific scrutiny. And the conclusion is that Snowball really can dance.

Aniruddh Patel of the Neurosciences Institute in La Jolla, California, and his colleagues say that Snowball’s ability to shake his stuff is much more than a cute curiosity. It could shed light on the biological bases of rhythm perception, and might even hold implications for the use of music in treating neurodegenerative disease.

‘Music with a beat can sometimes help people with Parkinson’s disease to initiate and coordinate walking’, says Patel. ‘But we don’t know why. If nonhuman animals can synchronize to a beat, what we learn from their brains could be relevant for understanding the mechanisms behind the clinical power of rhythmic music in Parkinson’s.’

Anyone watching Snowball can see that his foot-tapping seems to be well synchronized with the musical beat. But it was possible that in the original videos he was using timing cues from people dancing off camera. His previous owner says that he and his children would encourage Snowball’s ‘dancing’ with rhythmic gestures of their own.

Genuine ‘dancing’ – the ability to perceive and move in time with a beat – would also require that Snowball adjust his movements to match different rhythmic speeds (tempi).

To examine this, Patel and his colleagues went to meet Snowball. He had been left by his previous owner at a bird shelter, Birdlovers Only Rescue Service Inc. in Schererville, Indiana, in August 2007, along with a CD containing a song to which his owner said that Snowball liked to dance: ‘Everybody’ by the Backstreet Boys.

Patel and colleagues videoed Snowball ‘dancing’ in one of his favourite spots, on the back of an armchair in the office of Birdlovers Only. They altered the tempi of the music in small steps, and studied whether Snowball stayed in synch.

This wasn’t as easy as it might sound, because Snowball didn’t ‘dance’ continuously during the music, and sometimes he didn’t get into the groove at all. So it was important to check whether the episodes of apparent synchrony could be down to pure chance.

‘On each trial he actually dances at a range of tempi’, says Patel. But the lower end of this range seemed to correlate with the beat of the music. ‘When the music tempo was slow, his tempo range included slow dancing. When the music was fast, his tempo range didn’t include these slower tempi.’

A statistical check on these variations showed that the correlation between the music’s rhythm and Snowball’s slower movements was very unlikely to have happened by chance. ‘To us, this shows that he really does have tempo sensitivity, and is not just ‘doing his own thing’ at some preferred tempo’, says Patel.

He says that Snowball is unlikely to be unique. Adena Schachner of Harvard University has also found evidence of genuine synchrony in YouTube videos of parrots, and also in studies of perhaps the most celebrated ‘intelligent parrot’, the late Alex, trained by psychologist Irene Pepperberg [1]. Patel [2] and Schachner will both present their findings at the 10th International Conference on Music Perception and Cognition in Sapporo, Japan, in August.

Patel and his colleagues hope to explore whether Snowball’s dance moves are related to the natural sexual-display movements of cockatoos. Has he invented his own moves, or simply adapted those of his instinctive repertoire? Will he dance with a partner, and if so, will that change his style?

But the implications extend beyond the natural proclivities of birds. Patel points out that Snowball’s dancing behaviour is better than that of very young children, who will move to music but without any real synchrony to the beat [3]. ‘Snowball is better than a typical 2-4 year old, but not as good as a human adult’, he says. (Some might say the same of Snowball’s musical tastes.)

This suggests that a capacity for rhythmic synchronization is not a ‘musical’ adaptation, because animals have no genuine ‘music’. The question of whether musicality is biologically innate in humans has been highly controversial – some argue that music has served adaptive functions that create a genetic predisposition for it. But Snowball seems to be showing that an ability to dance to a beat does not stem from a propensity for music-making.

References
1. Pepperberg, I. M. Alex & Me (HarperCollins, 2008).
2. Patel, A. D. et al., Proc. 10th Int. Conf. on Music Perception and Cognition, eds M. Adachi et al. (Causal Productions, Adelaide, in press).
3. Eerola, T. et al., Proc. 9th Int. Conf. on Music Perception and Cognition, eds M. Baroni et al. (2006).