We experience our conscious mind as a single unified thing. But if Gazzaniga and company are right, it most certainly isn't. How could a “specialized and localized” modular brain give rise to the feeling of “oneness” we feel so strongly about? It would seem there are too many things going on separately and locally:
Our conscious awareness is the mere tip of the iceberg of nonconscious processing. Below our level of awareness is the very busy nonconscious brain hard at work. Not hard for us to imagine are the housekeeping jobs the brain constantly struggles to keep homeostatic mechanisms up and running, such as our heart beating, our lungs breathing, and our temperature just right. Less easy to imagine, but being discovered left and right over the past fifty years, are the myriads of nonconscious processes smoothly putt-putting along. Think about it.
To begin with there are all the automatic visual and other sensory processing we have talked about. In addition, our minds are always being unconsciously biased by positive and negative priming processes, and influenced by category identification processes. In our social world, coalitionary bonding processes, cheater detection processes, and even moral judgment processes (to name only a few) are cranking away below our conscious mechanisms. With increasingly sophisticated testing methods, the number and diversity of identified processes is only going to multiply.So what's going on? Who's controlling all this stuff? The idea is that the brain works more like traffic than a car. No one is controlling it!
It's due to a principle of complex systems called emergence, and it explains why all of these “specialized and localized” processes can give rise to what seems like a unified mind.
The key to understanding emergence is to understand that there are different levels of organization. My favorite analogy is that of the car, which I have mentioned before. If you look at an isolated car part, such as a cam shaft, you cannot predict that the freeway will be full of traffic at 5:15 PM. Monday through Friday. In fact, you could not even predict the phenomenon of traffic would even occur if you just looked at a brake pad. You cannot analyze traffic at the level of car parts. Did the guy who invented the wheel ever visualize the 405 in Los Angeles on Friday evening? You cannot even analyze traffic at the level of the individual car. When you get a bunch of cars and drivers together, with the variables of location, time, weather, and society, all in the mix, then at that level you can predict traffic. A new set of laws emerge that aren't predicted from the parts alone.Emergence, Gazzaniga goes on, is how to understand the brain. Sub-atomic particles, atoms, molecules, cells, neurons, modules, the mind, and a collection of minds (a society) are all different levels of organization, with their own laws that cannot necessarily be predicted from the properties of the level below.
Read the whole thing here: Who's in Charge of Our Minds? The Interpreter