Because one cannot reliable test such assumptions due to multiple very different factors in play (multiple causation). "Prefrontal cortex as the seat of rationa

Because one cannot reliable test such assumptions due to multiple very different factors in play (multiple causation). "Prefrontal cortex as the seat of rational brain" is just a meme - a huge over-simplification, as rationality itself. It is more sane to talk about control of emotions - ability of an activity in one region of the brain interfere with, or tame other activity in a different region, which requires "training" of appropriate "networks" via repeated exposure to certain behavioral patterns (experience). This could be attributed to ageing, that adults just had more practice of self-control, but it will be just another meme, because each process of maturation is unique, due to almost intractable number of factors involved. Even cross-culturally, my beat is that if some could compare group of "typical US students" with a group of Asian "Buddhist monks" of the same age, there will be significant differences in prefrontal cortex activities.) Read some Marvin Minsky for great good.)