According to MacLean, the oldest part is the brain stem, sometimes called the reptilian brain because it does things that even lizards can do, like regulating instinctive behaviors and motor functions. The second is the limbic system, or paleomammalian brain, which is more recently evolved and translates basic stimuli into emotions that we feel, signaling to us what’s going on around us and thus how we should react. Finally, there is the neocortex, which MacLean suggested is the newest part—the most human, or neomammalian, brain. This is the part that governs decision-making, perception,
...more
