No one knows exactly why. But new research is shedding light on this ubiquitous human phenomenon.

Animals that dance

Snowball, a sulphur-crested cockatoo, proved that a nonhuman animal could move in time to a beat in a groundbreaking study led by neuroscientist Aniruddh Patel, PhD. Our closest genetic cousins, chimps, don't move to the beat of music. Neither do dogs or cats, even though they've lived and evolved alongside humans for millennia. This research, says Patel, suggests that dance may have evolved as a byproduct of our ability to mimic sounds -- a rare ability shared by humans, cockatoos and parrots.

Good dancers make good mates

Good dancers may make good mates -- at least from a genetic standpoint, finds research by psychology professor William Michael Brown, PhD. He used motion-capture technology to record the movements of 40 dancing Jamaicans. The researchers reduced the dancers to stick figures to remove any cues about the dancers' bodies and attractiveness. Then, a different group of Jamaicans watched videos like the ones below and greatly preferred the dances of people who had symmetrical bodies. Symmetry, explains Brown, appears to be a good indicator of how healthy a person is, and could indicate good genes, as well.

Dance: A universal language

Dance is also a powerful tool for expressing emotion -- one that can cross cultural divides, according to a study by psychologist and dancer Ahalya Hejmadi, PhD. Hejmandi recorded herself portraying 10 emotions as described in the "Natyasastra," a 2,000-year-old Indian text that's the foundation of classical Indian dance. Both the American and Indian viewers who participated in her study had no trouble identifying the emotions that Hejmadi danced.