reveals the mechanisms by which the consciousness we usually think of as our
whole mind is influenced by other parts of our mind which are hidden from our
conscious.
The earliest stage is the ̳reptile brain‘. This part of the brain handles our
physical activities, such as coordinating movement and directing responses to
certain stimuli. Just like a lizard scampering away when it senses a threatening
shadow, we automatically recoil from physical pain. This is the part of the
brain that regulates all the unconscious physical processes continually at work
in our bodies, such as heart beat, breathing, digestion, etc.
The middle stage is the ̳mammal brain‘. This part is responsible for our
emotional responses. Our emotions are obvious to us, but you can also see
them in Fido‘s energetic tail-wagging when you come back from vacation.
The emotional part of our brain is what associates good feelings to positive
memories and bad feelings to negative ones. While the reptile brain pulls us
away from negative stimuli and towards positive stimuli that are programmed
instinctually, emotions give us the ability to develop quickly the appropriate
response to new situations we encounter.
Emotions are a way to carry pain and pleasure inside of us. Instead of
relying solely on physical responses, we also use related emotional responses
to guide our reactions. We avoid people who hurt us, feel disgusted by foods
that make us sick, express gratitude for those who help us, and feel confident
about things we can do successfully.
The final stage of the brain is the thinking brain, which is where our
consciousness and reasoning abilities are found. Extremely versatile, the
thinking brain lets us evaluate in advance the desirability of an experience. We
can learn to avoid electrocution by being warned about it or seeing someone
else suffer this fate, and we can learn to hunt or cook from the explanation
and examples shown by others.
The reptile, physical brain is responsible for what we commonly think of as
―body‖. The mammal, emotional, brain we typically consider ―heart‖, and the
thinking brain is what we‘re really referring to by ―mind‖.
Each level is just a more complex evolutionary reaction to dealing with
stimuli. First we developed basic responses to current body sensations like
hunger and touch, then we developed the more complex response to past
sensations in emotions like happiness and sadness, and finally we developed
the startling ability to respond to the possible future with thought. What‘s
important about this hierarchy is that each level is built on the ―lower one‖.
The three brains, according to this theory, are actually built around each
other in our heads.