In the traditionally taught view of perception, data from the sensorium pours into the brain, works its way up the sensory hierarchy, and makes itself seen, heard, smelled, tasted, felt - "perceived." But a closer examination of the data suggests this is incorrect. The brain is properly thought of as a mostly closed system that runs on its own internally generated activity.
David EaglemanWhen one part of the brain makes a choice, other parts can quickly invent a story to explain why. If you show the command "Walk" to the right hemisphere (the one without language), the patient will get up and start walking. If you stop him and ask why he's leaving, his left hemisphere, cooking up an answer, will say something like "I was going to get a drink of water."
David EaglemanConstant reminding ourselves that we not see with our eyes but with our synergetic eye-brain system working as a whole will produce constant astonishment as we notice, more and more often, how much of our perceptions emerge from our preconceptions.
David EaglemanAs Walt Whitman correctly surmised, we are large and we harbor multitudes within us. And those multitudes are locked in chronic battle. There is an ongoing conversation among the different factions in your brain, each competing to control the single output channel of your behavior. As a result, you can accomplish the strange feats of arguing with yourself, cursing at yourself, and cajoling yourself to do something - feats that modern computers simply do not do.
David EaglemanYou gleefully say, "I just thought of something!", when in fact your brain performed an enormous amount of work before your moment of genius struck. When an idea is served up from behind the scenes, your neural circuitry has been working on it for hours or days or years, consolidating information and trying out new combinations. But you take credit without further wonderment at the vast, hidden machinery behind the scenes.
David Eagleman