@DrewDad,
I agree kids under 12 can do it, more so as they get older....but it generally blossoms the hell after about 12, as very important areas of the brain develop like crazy during puberty.
Since there is great brain plasticity, especially (but, research is more and more discovering, not only) when we are young, I suspect classes like the ones dewscribed in this thread would really help build kids' capacity for that.
It must certainly be supporting the development of reflective capacity, which is enormously important to emotional as well as intellectual development.