As 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.

Odor carries a great deal of information, including information about a potential mate's age, sex, fertility, identity, emotions, and health.

Your brain is built of cells called neurons and glia - hundreds of billions of them. Each one of these cells is as complicated as a city.

Societies would _not_ be better off if everyone were like Mr Spock, all rationality and no emotion. Instead, a balance - a teaming up of the internal rivals - is optimal for brains. ... Some balance of the emotional and rational systems is needed, and that balance may already be optimized by natural selection in human brains.

Behavior is the outcome of the battle among internal systems.

There are always wonderful mysteries to confront.

Consciousness is the smallest player in the operations of the brain.