Several days ago in the book on NLP I'm reading it talked about motivation and how there are basically only two kinds of motivation; positive and negative -- Reward or punishment basically. It talked about how the most effective strategy to motivate anyone is to use a combination of the two in the right mix (and even the order the combination is presented is important for maximum effectiveness).
It also went on to say that any given person tends to rely almost exclusively on one of the two, and trying to force feed them techniques only geared toward the kind of motivation they don't use won't work. How positive motivation is a more steady type that keeps a person working toward whatever reward they have their eye set upon, and those that rely on negative motivation gets motivated in streaks where they become highly motivated and then nothing when the discomfort/pain diminishes.
What also caught my eye about the negatively motivated people was that by the very definition they are moving away from the cause of the pain/discomfort as opposed to the positively motivated people who are moving toward their reward/pleasure. It went on to say how too much negative motivation to those negatively motivated is also counter productive as when they overload on what motivates them they will turn inwards and instead of doing what is needed on the physical level to move away from their problems will move away mentally and just shut down.
It also said how positively motivated people are the dreamers and planners of life and the negatively motivated ones are the problem solvers that anticipate problems and try to avoid those problems.
It was interesting reading.