The part of the brain that is always on the look out for life threatening situations is the amygdala. It is the part of the brain that acts when it perceives a threat without waiting for the neo-cortex, the thinking part of the brain, to identify whether it's a real threat or not. Problem is, the amygdala often gets it wrong. And amygdala is Greek for almond. It also has the shape of an almond, so we get The Almond Effect.