The pictures on ZPD appeared to be useful so please examine the pictures in this old post from my old Cognitive Dissonance blog.
On Context
A person exists within his or her own context which is, in turn, embedded in a larger global context. Each person has an archive that is both internal (memory) and external (artifacts) which help the person operate in context.
There have been posts about the notion of teacher as bridge between known and unknown in our discussion of ZPD, and this notion is echoed here altho perhaps not in the way you’re all thinking. As you consider ZPD, remember that it’s not something that “students have” but rather a general descriptive map of knowledge with the places where the fertile ground is highlighted. It’s not that some people have “high ZPD” or “low ZPD” but rather how much of a given domain is available to an individual. The irony here is that somebody with a very shallow knowledge base on a very large set content domains is going to be an ‘easier’ student to teach because their ZPD is going to be — for lack of a better term — wider and the teacher will have less bridging required.