In my discussion with Rachel, it occurred to me suddenly that a lot of my internal narrative has been shaped by The User Illusion. Tor Norretranders’ book is about quantum physics, the nature of consciousness, and how all that data that comes shooting at us every moment of the day actually does have an impact, even if we can’t possibly hope to consciously know it.

The bit that stuck out for me in relation to mapping related to what happens when two people are talking: as the conversation progresses, each person forms a tree of options (both topics and other peripheral data) which they use to draw on when they next speak. The deeper these branches reach, the more involving the conversation becomes. But it’s a negotiation of depth, because the knowledge shared between the two people must be assessed to know which steps up the branches can be skipped. At first, with a stranger, we have to work a lot to determine this, but with friends or after establishing common knowledge, the conversation can skip most of the lower branches and head straight for the higher levels. These mental maps are literally used to navigate the conversation. This may seem straightforward on the conscious level, but actually most of this branching occurs not in relation to the conversation topic itself, but to subconscious cues relating to speech patterns, body language, vocabulary, perceived social goals, etc.

As a side note to demonstrate how far-reaching Norretranders’ ideas are, one of my favorite nuggets from the book can, I think, explain the whole of human history. I don’t have the exact quote handy, but the idea is that because the bandwidth of communication between two people is so much lower than the bandwidth of information our brains are receiving, there’s no imaginable way we could ever describe our experience to another human being. That, says Norretranders, is the great tragedy of being human. I think it’s an elegant notion, and can explain everything from war to art to love. Needless to say, I highly recommend the book to everyone; it has changed the way I think about design and interaction, but also communication as a whole.