Assessing and reacting to risk is one of the most important things a living creature has to deal with, and there’s a very primitive part of the brain that has that job. It’s the amygdala, and it sits right above the brainstem, in what’s called the medial temporal lobe. The amygdala is responsible for processing base emotions that come from sensory inputs, like anger, avoidance, defensiveness and fear. It’s an old part of the brain, and seems to have originated in early fishes.

Read the entire article here. (Schneier.com)