It focused your attention and senses on the saber-toothed tiger and your surroundings, making sure no stray thoughts distracted you from the threat at hand. The alarm system also prompted a complex change in brain chemicals that inhibited your prefrontal cortex, the area of the brain in charge of impulse control. That’s right, the fight-or-flight response wants to make you more impulsive. The rational, wise, and deliberative prefrontal cortex is effectively put to sleep—the better to make sure you don’t chicken out or overthink your escape.
