In this TED talk, Michael Shermer discusses how humans are pattern seeking and tend to find faces in anything from toast to a drying window. From an evolutionary standpoint, we are primed to recognize faces for our own safety. Is it mom, the person who provides food? Or is it the enemy who means to kill me?
Interestingly, if you watch the video from 9:20 to 11:05, you will see how powerful auditory priming is. Notice how before Shermer primes your brain with new lyrics, not much about the backwards track is coherent. But when he shows what you are supposed to hear, it is clear.