Young people are more open minded, but I think it has to do with learning more than anything else. Young people who's brains have not fully developed learn things much easier than older people, or so I've gathered from talking to older people. For example, a guy who was maybe... 40 onced asked me how long I'd been playing guitar. He said he'd like to learn, but it would be difficult to enter such new concepts because he said he's older and he can't absorb it like he once could. I don't think its a P or J thing, its just congnitive development.
And I don't think its fair to say there must be more N's because we've gotten more intelligent or vice versa. First, IQ measures how well you can do an IQ test, it can't really be trusted as a way to measure the full capacity of one's intellect, its shakey. N is only one aspect of intelligence, its intelligence working in one way. S is just as intelligent, it just works differently.
I think teens are, MBTI wise, more or less the same as adults.
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