The first brain (brain stem) is the seat of autonomic or automatic response, as well as the seat of habits. It connects us to our external world through our skin, our pores, and our nerves. It controls what impulses get recognized and passed along to the two higher levels. This brain learns through imitation, avoidance, and repetition until something becomes habitual. Information usually enters at this point without our conscious awareness. We can make much of this information conscious and use it to our benefit, as biofeedback and hypnosis have shown us.

The emotional brain (limbic system) helps us know what things to approach and what to avoid by guiding our preferences. As we move through life and have more experiences, we have stronger intuitions, hunches, and gut reactions because more things are stored in the limbic warehouse. We have "learned" from experience. Intuition is emotional learning gained over many years; a 14 year old has little intuition because he or she has not experienced enough life to make connections between experiences. As we mature, we accumulate more reliable emotional data that can offer us valuable clues and guide our behavior, providing we become aware of its existence and learn how to interpret it. Unfortunately, many adults have been taught to ignore this type of information.

The rational brain (neocortex) assists us with functions related to thinking and language: planning, questioning, making decisions, solving problems, and generating new ideas. This layer is connected to the emotional brain with millions of connections, allowing the emotional and the thinking brains to influence one another in a myriad of ways and providing rich data on which to draw conclusions and initiate action.

Our emotions have helped us immeasurably over the course of human evolution. Emotional responses are milliseconds faster than cognitive (thinking) responses; the lightning-fast reactions that bypass the rational brain centers were often survival responses for our distant ancestors. The limbic brain sends us the warning of a crisis before the rational brain can even process the incoming signal: the body has been alerted, and is ready to act on our behalf.

The emotional brain was conserved for a purpose. Today, physical survival is less of a threat than it was to primitive man, but data from the emotional brain still gives us important clues to our surroundings and the actions we need to take. Ignoring this data on purpose or because we aren't aware of it leaves us with only partial information. One of the purposes is to show how emotions can be used to maximum effect without getting out of control.

Research on Emotional Intelligence
Here are some additional conclusions from evolutionary science:

Our emotional brain and its responses have been shaped and preserved over millions of years of evolution. Humanity is "hard-wired" for emotional response!

The facial expressions for basic emotions such as fear, sadness, disgust, anger, and pleasure are identical across cultures, indicating some inborn genetic mechanism common to the human race.

Very, very early in evolutionary history, simple "beings" had brainstems that regulated autonomic function and kept them alive. Human beings still have a brainstem, located just above the spinal cord, which tells our lungs to breathe and our hearts to beat. Similar in architecture to the brainstem of reptiles, the human brainstem it is sometimes called the reflex brain or the first brain. We can summon it to conscious awareness, although it usually functions automatically.

The limbic system or emotional brain is thought to have developed out of the first brain. It helps us store and remember past experiences and learn from them. The limbic system in humans is located in the approximate center of the brain; when information enters the limbic system, we experience bodily sensations, transmitted by the peptides or chemical information substances, in the form of a "reaction" to the stimulus with much more awareness of what is happening than at the level of the first brain.

Out of this limbic system came the rational (thinking) brain or thin cortex. The cortex enables us to comprehend sensory information and plan accordingly. The very thin outermost layer of the cortex called the neocortex is responsible for higher order thinking and symbolic communication, art and ideas, and long-term planning. The millions or billions of connections between the limbic brain and the thinking brain allow for the free-flow of information between these layers.