I am an alien from outer space who is visiting a planet called Earth. The species living here, humans, have a very primitive and strange culture. They seem to spontaneously burst into dance and song, performing long musical performances at random notice. The topics involving these musical numbers can involve anything ranging from love in a relationship to discovering a magic lamp. This can grow to be very irritating, as a simple conversation with one of these idiots can erupt into a long musical number when a simple answer would have sufficed.
This bizarre nonsense usually starts off with one person at a time. They normally complain about their woes or some aspect of their life, and begin singing loudly. This could occur in an isolated spot or a heavily populated area. This singing eventually leads to body movements which I interpret to be what passes for dancing in this species. The effect seems to be contagious, as any passers-by are affected and join in, extending the range and effect to others. Soon, hundreds or even thousands of random strangers join in the number, despite having no relation to each other. The performance appears to have been perfectly choreographed, as everyone is on cue and NSYNC with each other, despite having no previous contact. This can go on for minutes, until the performance is over and everyone goes back to what they were doing before.
This strange occurrence is unique compared to all the other species I have observed. I am currently studying them to discover why this happens, and whether the effect stems from something biological, mental, or cultural in their society. It may simply be a mix of all three in some way. How can I explain this bizarre behavior?