In Saturday’s New York Times Opinion page, an article by Dr. Andy Clark, do-thrifty-brains-make-better-minds (read the entire article using this link), describes the thrifty nature of the human brain. Essentially, our brain matches current stimuli (things we see, hear, smell, or emotions, drug states, etc.) with previous experience and predict what will happen next. We behave according to those expectations.
Some important principles:
1. We only process small pieces of environmental stimuli and fill in the blanks with what we already know. Remarkably, we experience sights and sounds as complete pictures (even though we are actually only processing pieces).
2. We are more likely to process unexpected information. If there is an error in “filling in the blanks” we attend to it.
3. Almost the entire process occurs without awareness.
4. Your brain is always engaged in this process.
An example is, after driving a manual transmission for years, you step into an automatic (by the way, many of you have already filled in the blank of the rest of this sentence). Your brain recognizes car, and all of its componenents, so it predicts a pedal to the left of the brake (the clutch). You unconsciously try to step on it and find only air. When your brain registers the mistake (which it does before you are even aware of it), you become conscious of what you should do instead.
I cannot overstate how complex and remarkable this system is.