How to act not only is influenced by the feelings and thoughts, but by our evolutionary brain. From the life he began to dominate the planet, living beings according to their needs and their environment were evolving to become what we are today, had to pass millions of years before humans become the only living being with the ability to think and reason their behaviors, but before that, our brain was little by little also was subjected to changes and transformations that did grow to the extent the demands of learning the ancient humanoid needed. Within our brain evolutionarily found a complex of 3 mini brains that somehow influence the way we behave and how he decided to in our lives. This theory was exposed several years ago by Mr. Paul Mac Lean, named TRIUNE brain, which divides the brain in 3 evolutionary micro-complejos, the first derivative of our more ancient ancestors called reptilico brain, which dominates all our basic needs and makes us act solely and exclusively by impulse, as well as influence us in many of our instinctive performances, the second mammalian brain that I call it emotional, because it is part of the complex that acts dominated by emotions and feelings. The third and last is the rational brain, that thanks to him we are capable of thinking but also behave like machines without taking into account many times the feelings and impulses. Three brains continually fight between them when dominate our behaviour is, why the saying analyzes thinks and acts has more background to what we imagine and has an intimate relationship with these three brains that dominate each other the way we make decisions in life. It is important to take them into account and to differentiate which of these three is the dominant in our lives because they are fundamental basis to identify our potential and our talents.