Understanding the basic neuroscience of how our brain works helps to faster understand and develop the skills of emotional intelligence. For this reason, we are going to look to the brain model formulated in 1966, by the neuroscientist Paul D. MacLean - the triune brain. Although, this model is a highly simplified explanation of brain activity and organization, it provides an easy-to-understand approximation of the hierarchy of the brain functions.

In 1990, in his book The Triune Brain in Evolution--MacLean look to the evolutionary theory to describe the brain in terms of three distinct structures that emerged during the evolution of the human body. The primitive brain was the first brain layer to emerge, followed by the emotional brain (limbic system) and the rational brain (cerebrum). The following figure shows us the structure of the triune brain: