The multiple reinforcing cues of a good song—rhythm, melody, contour—cause music to stick in our heads. That is the reason why many ancient myths, epics, and even the Old Testament were set to music in preparation for being passed down by oral tradition across generations.

Primates, some birds, and humans have mirror neurons... that fire both when performing an action and when observing someone else performing... We've found mirror neurons in Broca's area, a part... involved in speaking, and learning to speak. ...our mirror neurons may be firing when we see or hear musicians perform ... in preparation for being able to mirror or echo them back as part of a signaling system.

During the first six months or so of life... the infant brain is unable to clearly distinguish the source of sensory inputs; vision, hearing, and touch meld into a unitary perceptual representation. ...inputs from the various sensory receptors may connect to many different parts of the brain, pending pruning that will occur later in life. As Simon Baron-Cohen has described it, with all this sensory cross talk, the infant lives in a state of complete psychodelic splendor (without the aid of drugs).

Cosmides and Tooby argue that music's function in the developing child is to help prepare its mind for a number of complex cognitive and social activities, exercising the brain so that it will be ready for the demands placed on it by language and social interaction. ...Mother-infant interactions involving music almost always entail both singing and rhythmic movement...

It is only in the last five hundred years that music has become a spectator activity—the thought of a musical concert in which a class of "experts" performed for an appreciative audience was virtually unknown throughout our history as a species. And it has only been in the last hundred years or so that the ties between musical sound and human movement have been minimized.