Today I was turned on to Paul MacLean’s Triune Brain Theory, and I must say that it’s pretty interesting. The idea he puts forward is that the human brain is made up of three seperate brains in one, which are:

• The R-complex, or reptilian brain, which would be the most basic of the three. Developed during early stages in our evolution (in case the name wasn’t obvious enough) the reptilian complex is responsible for basic brain functions such as movement, digestion, reproduction, circulation, breathing, and the execution of fight-or-flight reaction.
• The Limbic system, or mammal brain, which were developed during a middle stage of our evolution. The mammal brain includes the amygdala, responsible for associating events with emotion, and the hippocampus, which provides our long-term memory. Love, hate, fear, joy, pity, rage come from the limbic complex.
• The Neocortex (sometimes called cerebral cortex), or human mind, which occupies five-sixths of the space within our heads. The cerebral cortex gives us communication, logic, operational thinking, and the ability to plan.

The idea suggests that - in spite of how civilized we’d like to think we are - the Neocortex doesn’t run the show. In fact, it’s only when the two underlying brains are not in control that the Neocortex gets to run the show. In modern society, we find our basic needs met, so we’re able to feed our human mind, but order of importance starts from oldest-to-youngest.

This is the part that really starts to get fascinating for me, because it makes so much sense. It explains why, when faced with a dangerous situation, we do things we didn’t know we were capable of - often without emotion, and we often have a very cloudy memory when it’s done. It explains why even the smartest people we know make such horrible decisions when they think they’re in love… or for that matter when they’re irate, as well.

I’m always the one to say that the reason for everything we do is written in our DNA - particularly when I’m talking about relationships and/or sex - but this gives me a whole new depth to the idea. Indeed, it’s really quite fascinating how much of human nature seems to be something we have little ability to do anything about!