I've had theory for years that people are either a "focus" or a "scatter". Now, I don't mean scatter brained, although that can happen ;). I’m talking about the way people work and function in their lives.
Focus's usually have a very narrow and intense way of doing things. In school they often excel at whatever topic they study. My former thesis adviser is an excellent example of a focus. When I met her she was only 27 and was already a tenured professor at a University. She also had spent time with the World Health Organization in Geneva. At 27. Scared the crap out of me for reasons you'll see very quickly.
I, on the other hand, am an example of a scatter (stop laughing folks ;)). Someone as intensely aimed at their area of study like my thesis advisor was a bit unnerving for me. Scatters find so many things interesting that we rarely get to the level of intensity that a focus does. The extreme case is a scatter brain, or someone who can't get through school, or go after goals because of too many distractions.
Both types in the extreme can be problematic. Scatters may fail to reach their potential if they can't put some blinders on and focus. The focus folks can miss out on many things in life if they become too obsessed with a single subject. I'm thinking my former advisor did NOT have a rip roaring fun time in college-LOL!
But both types have strengths as well. If the object of the focus’s intense dedication falls through, they may find themselves at a loss. But the scatter can pick up and find another topic with ease. The focus can get to a level of depth within a subject, which would be difficult for a scatter.
Now how does all this relate to writing you ask? It affects both your characters as well as you the author. Understanding where on the sliding scale of focus your characters lay can help you keep their behavior consistent and believable.
Understanding your own position on the scale can help you keep your writing form in top shape. You need to understand how your mind and personality work best so that you can keep moving forward in your writing career. Now it doesn’t mean that a scatter can’t become more focused and visa versa- but before anything can change, you have to understand what’s there to begin with. True for our characters and ourselves.