JoeB wrote:Mr.Samsa wrote:In other words, the validity of introversion and extroversion doesn't help the MBTI because they characterise them incorrectly (and, perhaps more importantly, it's only a quarter of the personality categories that it proposes, with no evidence at all that the other categories exist).
What would constitute evidence for the existence of the four categories?
There are a number of ways to assess whether they exist, but essentially they need to be demonstrated to be consistent, reliable, and foundational across individuals - but only introversion/extroversion is. The wiki page has a good discussion on the construct validity of the test
here.
JoeB wrote:I'm a bit confused by the antipathy towards MBTI, it's said that it only tells you what you put in, but isn't that its entire purpose, to describe what type of person you are?
That's a common understanding of how personality tests work, but it's false. This test, as it is, describes what kind of person
you think you are - in other words, there's no point even doing the test as you could simply just ask a person to describe themselves, and you'd get the exact same results. A lot of personality tests don't rely on self-reported data because it can be faulty, but when they do use self-reported data (through the use of tests like this) they include a number of methods and techniques that are designed to reduce cognitive biases and common mistakes people make (e.g. presenting themselves in a more positive light, or answering a question in the way they think is appropriate rather than in the way that is most accurate).
JoeB wrote:I've done the test several times and it's quite consistent (INFP) and in other persons its quite consistent as well.
That's good for you, but you're an exception. The MBTI is notorious for having no reliability; for most people, when they retake the test months later we find that their "personality" has shifted dramatically across most MBTI measures, and there are also reliability problems within the test itself (i.e. if you take the results from one half of the test, and compare them to the results of another half of the test, you can get vastly different personality type results, and this should never occur).
godel wrote:Mr.Samsa wrote:Whilst Jung was one of the first to popularise the notions of intro and extroversion, he obviously didn't come up with the concept, and the way he (and the MBTI) conceived of the characteristic is now seen as demonstrably false. That is, the concept itself is valid, but Jung and the MBTI-ers view the categories as being more discrete, whereas we know that they are continuous.
Ok, so let's assume Carl Jung was a "nut-case" popularist for a minute.
It would be good to know where one can find the authoritative definition of "Extraversion", and who is responsible for it in a psychological sense.
Perhaps you can enlighten us?
The modern form of the I-E scale is that which is utilised with Costa and McCrae's "
Big Five". The main difference between that, and the outdated rejected form that Jung used, was that current theories view I-E as a continuous scale and not a dichotomous category.
by 
