In this TED Talk neuroscientist Daniel Levitin explains what happens to the brain under stress and how we can prepare ourselves to stay calm in difficult situations. When we’re stressed the brain releases cortisol which clouds our judgment and makes us more likely to make mistakes. Levitin shares a personal story about locking himself out of his house while traveling and uses it to show how stress can cause poor decision making. He introduces the idea of the premortem a technique where you imagine something going wrong before it happens, so you can take steps to prevent it. For example, keeping a spare key or organizing medication in advance. His message is that planning ahead can help us manage stress, avoid panic and make smarter decisions when life gets tough.