Science has figured out why songs get stuck in your head.

Those tunes are called earworms, songs or pieces of music you hear and then seemingly keep hearing, over and over again.

No serious study of them has been done until now. Scientists have a name for it - involuntary musical imagery, or INMI. They found it mostly happens during "time filler" activities, like waiting in line.

Research now shows earworms are more tied to our motor systems than rational or cognitive thought, and are more likely to be tunes we can sing, hum or tap along to, which ties it to physical activity.

--Rob Archer