Science has advanced our understanding of the brain a great deal, particularly in the last 20 years. We even know that the speed of mind operates on a scale of milliseconds — in other words, mental speed is measured in thousandths of a second. In fact, it takes 300 milliseconds longer for a signal to travel from the thalamus and to the neocortex than to reach the amygdala, where an emotional response is generated. The brain works so fast that 300 milliseconds is enough time for the amygdala to synthesize that information and generate a response before the rational brain receives the signal.