Our current brain is the result of millions of years of evolution. Although it is an organ that works by interconnecting all its areas, we could divide the brain into three different networks: instinctive, emotional and cognitive-executive only for teaching purposes.
These networks or systems emerged at different evolutionary stages and showed characteristic functions. While the instinctive system has focused on ensuring survival and allowing the transmission of genetic material to future generations, the emotional system has allowed us to model automatic responses and learn. The association of a new experience with a situation of pro-survival or a contra-survival, will determine that an such experience is recorded in memory as pleasant or painful, respectively. The cognitive-executive system is what differentiates us from other species, some of its capabilities are: reasoning, thinking, evaluating, vetoing emotional impulses, making plans, developing strategies, communicating through verbal language and self-motivation.
While the end result is the functional integration of these three networks, the operation is performed in a stepwise manner due to the difference in the speed of action between them. Therefore, the cognitive-executive system turns on after the activation of automatic primitive systems (instinctive and emotional). This knowledge is vital to assess when the primitive impulses are guiding our behavior.