There was a great piece in a recent New Yorker that had a journalist following a brilliant young neuroscientist around chatting about his varied interests and research. The piece covered a lot of ground and there were a number of really great observations and insights into how the brain mediates perception. I’d long known that the system processes latency (signals in your nerves take time to travel from the point of reception to the brain – it takes longer for a pain signal to reach your brain from your toe than from your cheek for example) by mediating your sense of time so that things appear to happen instantly when in fact they don’t. Turns out this is just the tip of the iceberg – the brain edits more out than I knew. The piece offered a great little experiment you can conduct to see evidence of your brain doing this. Imagine you were watching someone else look into a mirror, and that person was looking at their eyes, changing their focus from their left eye to their right eye repeatedly. You would see their eyes move as they changed focus. You can film yourself doing this and see it happen. Now go look in a mirror. Look from your right eye to your left eye repeatedly. You will never see your eyes move. They do move. Your brain just filters it out of your conscious perception, presumably as extraneous detail, much as it does with the majority of sensory input you experience as you move through the world. On the one hand, banal, right? On the other, it’s a bit mind blowing to think about how you’re walking around with this subconscious editorial process constantly firing on all cylinders. Why don’t I get to make these choices! (a possible answer is that some people can, or have an altered editorial filter. We call them insane). Anyway, fascinating stuff and I loved the simple little test you can do to see this in action.