That factoid has been pretty thoroughly debunked: the original study did not test people beyond their mid-20s, and the finding was "brains continue developing f

That factoid has been pretty thoroughly debunked: the original study did not test people beyond their mid-20s, and the finding was "brains continue developing for as long as we tested". The most current understanding tells us that brains never stop developing. So there's no specific line we can draw and say "before this point, people's brains are not fully developed, and thus they should be treated as children; after this point, they are fully developed, and we should treat them as adults." Not even in the usual kind of population-average way. Yes, all else being equal, younger people have less experience, understanding, and ability to reason logically than older people who have gained experience, learned more things, and practiced logic. And yes, there's absolutely a period of childhood where many of our particular cognitive faculties are still developing for the first time. But "your brain is only fully developed once you hit 25 years old" is absolutely untrue.