By emergent ability I mean this: suppose that competently performing ability Z is contingent on, and only on, having skill X and skill Y developed to a certain level (that is, ability Z is a non-linear combination of ability X and Y that is distinct in type from those abilities).
You would see a person developing, slowly, their abilities X and Y, and then, when they have developed them sufficiently, one would suddenly observe ability Z.
I am interested in this question because it might seem like ability Z is a neurally innate ability that is suddenly triggered by some experience, when in fact this ability is just a combination of other abilities.
My question is perhaps two-fold: Do these sorts of abilities exist, and if so, what are some examples?