i dont know how deeply embedded an idea has to be to become a meme. one
could argue that the brain's strategies for face recognition are a very
powerful, leaky meme, but is that too complex an object?
Face recognition isn't a meme at all. The idea of face recognition is.
Talking to people about it only alerts them to the existence of a
hard-wired pattern recognition 'solution' employed by the brain. It does
not enable people whose face-recognising abilities are impaired or
non-existent to suddenly develop those abilities. It does enable clever
people to think about ways of building devices that may exhibit similar
strategies.
On the other hand, a wheel is a meme in its own right.