Cassius, the newborn behavior is best described as innate pattern recognition, which is different from both a faculty and a concept. Newborn recognition of the mother and the breast is similar to a sea turtle recognizing the ocean as the desired direction unless lights from humans disrupt the visual appearance.
A concept would require the infant to have an abstract thought about what they are seeing, smelling, feeling.
These pattern recognitions in other animals have been called instinct, and the prevailing belief was that humans didn't have instincts, lol.
It is more than a faculty-- it is an expectation of a particular pattern appearing and a recognition when it does. So there is definitely a sort of innate knowledge of those patterns, but non conceptual.
That is why the first time I read about the prolepses, I was flabbergasted that Epicurus figured this issue out. And then it was forgotten, and the "blank slate" took hold.
I will go even further and say that our innate pattern knowledge is connected to pleasure and pain. We have innate recognition of the sensory data indicating where to go for the pleasure of food. This was retained through evolution, as a memory of our species' common sources of pleasure and pain. Of course with individual variation, because we are not clones.
As we develop, other innate pattern knowledge emerges on a consistent schedule. Fear of the dark, for instance, is universal in early childhood. If a pattern knowledge were learned or required specific triggers, we wouldn't see it universally.
The innate pattern recognitions are added to by individual experiences over time.
Epicurus didn't say enough about the prolepses for me to be 100% certain he was referring to this issue. Part of my thought that he did might be because the word anticipations fit -- not just the ability to recognize a pattern but a prior anticipation of that pattern, followed by instinctive matching.
However, even though we can't be sure he understood this, which to me is as phenomenal as understanding indivisible particles, what he said is compatible with modern understanding of human development.