Don Norman dedicates the third chapter of The Design of Everyday Things to a discussion of knowledge in the head and knowledge in the world.
Knowledge in the head is anything you keep in your brain, from how a map works to your home address to thoughts like “pick up bread on the way home.” Knowledge in the world is anything you learn from the objects around you, from the map on the Metro to the name and numbers on your mailbox to the word “BREAD” written on your hand. Norman differentiates the two by contrasting their ease of use and their reliability:
Knowledge in the head is efficient: no search and interpretation of environment is required… Knowledge in the world is accessible. It is self-reminding. It always there, waiting to be seen, waiting to be used. [Norman, pg 80]
The distinction reminds me of the protagonist of Memento (2000). His short term memory loss causes him to tattoo himself with reminders and clues, so he can pursue a goal that extends beyond the capacity of his memory. It’s the sort of situation that can help you appreciate your own ability to store knowledge in your head. But even if most of us are decent at storing knowledge in our heads, it can get overwhelming at times. And that’s where knowledge in the world comes in handy.
Knowledge in the world “acts as its own reminder,” a particularly comforting and useful trait. I remembered this a few minutes ago, when my mind was racing, thinking of this and that — things I had to get done, but didn’t know quite how or when to do them. These thoughts and questions and to-dos were only going stay muddled if I left them “in the head.” A typical way to handle this may be to make a to-do list, but my stream of consciousness was too disorganized at this point for something as forward as a checklist.
I grabbed a notebook, and aimed to get the problems out of my head and into the world. Constraints on a task often help me, so I decided I’d write everything as a question, and it had to be quick. I didn’t have to stay on topic; I could go for proper brainstorming and just write it down.
I covered four pages of journal-sized paper with questions ranging in topic from work to play to “What should I name my betta fish?” As I progressed, my heart lightened and my brain calmed. I don’t have any more answers than I did before, but now I know the questions at least. They’re in the world and accessible, and that’s all I need for now.