I often come across the term "Shared environment" (as opposed to "Non-shared environment"). I think I understand non-shared environment, but shared environment is very confusing to me.
Can someone give a good explanation with examples please? Especially in regards to how can shared environment contribute to any difference at all in explaining variance?
I know the claim is that it explains very little, i.e. most of the variance due to environment is due to non-shared. But how is even a small variance due to shared environment possible? I mean, if two people (or siblings) went to different schools, and their income outcome was different, you could talk about the non-shared environment (school) that was different between them. But if they went to the same school, how can this shared environment contribute to any difference at all, even if very little.