The reason music with a simple recurring rhythm exerts a strong primordial appeal is that it reminds us of the womb environment  After all, the first sound heard within the womb is the comforting sound of the mother' s regular heartbeat  So in taking away from us the warmth and security of the womb, birth also takes away a primal and constant source of comfort
People seek sensations of warmth and security throughout life because birth takes away the warmth and security of the womb.
 Thus it is extremely natural that in seeking sensations of warmth and security throughout life, people would be strongly drawn toward simple recurring rhythmic sounds