Pareidolia

Surface

Pareidolia is a specific type of apophenia, the tendency to perceive a specific, meaningful image in an ambiguous visual stimulus. The face on Mars. Jesus in a grilled cheese sandwich. A man in the moon. The brain's face-detection system is so powerful and so hair-triggered that it fires on almost anything that vaguely resembles facial geometry.

Middle

Humans are the most social species on Earth, and faces are the most information-rich stimulus in our social environment. Evolution built a face detector so sensitive it generates false positives constantly. Seeing a face that isn't there costs nothing. Missing a face that is there, a predator, a rival, an ally, could be fatal.

Deep

Pareidolia is why religious icons appear in random objects, why we anthropomorphize robots and cars, and why horror is so effective at using suggestion. The brain completes the pattern before the conscious mind can intervene. We do not see the world as it is, we see the world as our evolutionary history prepared us to see it.