
A neuroscientist Paul D. MacLean was the person who revealed this theory after years of research in 1960s. He proposed that our brain was not one, but three interconnected brains, each one representing a distinct evolutionary step and each one possessing its own intelligence.
Each brain is connected to one another by the nerves and operates with a distinct intelligence, subjectivity, and memory. Emotion and thought, therefore, comes from two different but inter-connected brains – limbic brain (emotion) and neocortex (conscious thought).