Random Patterns Become Faces

I've had a number of experiences where I'll see faces in everything. Specifically walls w/ swirly drywall patterns, and really really easily in wood. I've wondered why we see faces in randomness like the man in the moon, the face on mars, wood grain, etc. This article (NyTimes) in typical empirical scientific fasion talks about how people process faces, but not why we see faces. My hypothesis is that its because a human face is probably the first thing we see, or at least make sense of what it is we're seeing. Out of the grey fog of non-vision your mothers face comes into view. Thoughts?