I've been on http://www.cognitiveprocesses.com/ and I've been doing some thinking. From what I understand, whether or not the person is an introvert or extrovert doesn't affect their dominant function. Maybe I'm wrong but I think it's possible for someone with a dominant extroverted function to be drained by people on a personal level. This has caused me some confusion because I've always associated lead extroverted function types with being people people. Also, I feel the online tests that distinguish between thinkers and feelers don't make sense, because everyone is thinking and feeling, what matters is how much of one you are and that functions order in the stack. The distinguishing between judging and perceiving doesn't make sense either because half the functions are judging (T/F) and the other are perceiving (S/N). As such, I've stopped relying on online tests to assess my own Myers Briggs type; most of them get it completely wrong and only serve to confuse new people like me. What matters more is your function order, the abbreviations like ENTP or INTJ don't mean much to how you actually process things. I've also noticed that most MBTI tests use language that attempts to steer the test taker towards a certain answer, or is ambiguous enough that the answer could always be different; this isn't good for getting accurate results. Anyway those are my current thoughts on the cognitive functions and their application to MBTI, please correct me if I got anything wrong.