I recently posted a description in a comment to a blog post of how I handle experience and level gains that I thought I should include on my own site. In considering how to write it, I realized it might be worth exploring a few other models of character development and learning as well.
Some Published Character Development Models
All character development models have some degree of abstraction to them, as a simple necessity. It is impractical or impossible to fully model in a game how people learn. However, different games model character development in different ways. Let’s start by looking them over.