Introversion/Extroversion

I like that Keirsy sorter, but it doesn't specifically help you determine whether you're an Introvert or an Extrovert (if you don't know already). I recently found a website that helped me understand those terms better--and the other factors in temperament. It's called Personality Pathways. It says this about temperament and learning:

In reviewing the comparisons in our inventory, you may find yourself drawn equally to opposing choices. In such cases I suggest you try to think back to how you were before the age of 12 or even younger if you can recall. The rationale for this suggestion is the fact that by the time we are 3 years old, the core of our cognitive organization is well-fixed. . . although the brain continues to allow some plasticity until puberty.

After the onset of puberty, our adult learning begins to overlay our core personality - which is when the blending of nature and nurture becomes more evident. For some people, this "learning" serves to strengthen what is already there, but with others it produces multiple faces to personality. Discovering or rediscovering this innate core of yourself is part of the journey of using personality type to enrich your life.

In other words, we're shaped by our temperament, but not doomed to it!