In our family, I find that it is mostly a function of how quickly a child picks up new concepts.
My gifted DD may only need to be exposed to a new concept one time to get it and remember it. But even she has weaker areas; it took her longer to master telling time with an analog clock than I expected, for some reason.
Our nongifted children may receive the same exposure, but have to go over it more times to master the new concept. In that sense, they need MORE exposure, I guess. It isn't so much a matter of reaching a magic age, but reaching a magic amount of exposure to an idea.
For example, when I read Harry Potter to all the kids, my gifted DD remembered the words of each incantation and what that spell did after a single hearing. My nongifted kids might remember an occasional spell, but are much fuzzier on the precise details of the story unless it is repeated to them.
Also, the nongifted kids are generally less interested in some of the intellectual stuff and that may be part of the reason WHY my gifted DD picks up concepts faster. She is simply paying closer attention. Of course, it's hard to say whether she pays closer attention because she gets it easier or whether she gets it easier because she pays closer attention.
