I wasn't referring to the extrovert tendency. I was referring to the tendency to start big projects and never finish them.

Ah, I understand. So you're saying he no longer fits his "profile". His knowledge has now altered the outcome of the test (hmmm, sounds like a short story I recently read, not to be confused with it's movie counterpart of the same title but inferior plot). Yes, that’s true. But where he benefited from the test was not only recognizing that he had trouble finishing things, but also that this was due to his lack of spending time in solitude. There are many reasons why people don’t finish what they start: lack of drive, lack of time, lack of ability, etc. He discovered that by forcing himself to get away from people (not a natural thing for an extrovert) he was able to be much more productive.