I’ve talked quite a bit about the how the brain perceives sensations, particularly pain. My general take has been that our sensory processes are not totally honest – sometimes you feel something is cold when it isn’t, sometimes you see things that aren’t there or vice versa (“I looked on the couch three times for my missing keys, and on the fourth, there they were.”) To some degree, our senses can’t be trusted.

I’ve been reading an interesting book called “World Wide Mind” which covers various topics related to integrating technology into our brain and bodies. It has a section on perception that is thought provoking. The book argues that our sensory experience of doing something is based on more than just the information we get from our nerves, but from our memories of similar experiences! (From pages 81-82.)

When your fingers touch [a doorknob], confirmatory signals flow up the nerves. But… the signals from your hand constitute only a fraction of your conscious experience of the doorknob. Your brain already knows that the doorknob is round, metallic and slightly warm, so it fills in those perceptions from memory rather than generating them from your finger nerves. The reason it does this is because it is more efficient to do so. Analyzing raw perceptions takes a lot of time and energy. It is much simpler for the brain to evoke the memory you have of the doorknob and let that constitute most of your conscious experience of it.

Obviously this theory can explain subjective experience during a short term period, like when you touch a doorknob, but I wonder if it explains a longer term human behavior. We’ve all seen people who say things like, “I can’t believe I let you talk me into going to Disneyland. The last three times I was there, I hated it and I know I’m going to hate it this time.” And hate it they do. But are they really experiencing Disneyland in the now, or the Disneyland of their memories? (I’m not saying they are actually lost in some reverie of the past, but that their memories are in some way coloring their current experience.)