This morning I took a few hours to go over the notes, reminders, and drawings in my journal for the last several months. Now I'm mulling over what I noticed. As I went, I made lists of concepts for the book, stories for the book, people i still need to talk with, and people i've interviewed thus far.

Reflection is a vital part of learning. It's like editing is to professional writing. If you're writing is going to be the best that it can be, you must revisit your work to tighten up, squeeze out the awkward parts, fix the grammar, and so on. If you want to retain and use what you learn, you must revisit it. If you learn something and don't come back to it in a day or two, at least half of it will have disappeared. On the other hand, if you want to plant something in memory for a good while, revisit it soon after first exposure and then again a week or two later.

Immediate repetition keeps thoughts from dropping out of your short-term memory, which has quite limited capacity. When you meet someone for the first time, the way to remember their name is to repeat it in replying to them. For longer-term memory, visiting something again strengthens the mental pathway to that idea. Repetition can be boring but it is useful for gluing things into place. More effective than that is linking what you've learned to what you already know. As James Burke, creator of the television series Connections, say, "Whenever you encounter a new idea, make a connection."

Sometimes my mind churns new concepts or ideas for days before coming up with productive new connections. Other times they never arrive at all. That's okay.

It is a lot more time-consuming to learn stuff over and over (like, right before a test) than it is to never let go, by reflecting on what's new.