Stress: a term that defines the everyday lives of many people. But how does stress affect social interaction? Comparative psychology comes to different conclusions: Sometimes stress makes us aggressive (in the sense of fight-or-flight), while other times it makes us vulnerable, helpful and generous. Two different stress messengers in the brain are responsible for these contrasting social behaviors. In his lecture, Prof. Dr. Tobias Kalenscher (Heinrich Heine University) shows that stress does not promote either one or the other behavior, but both at the same time and explains the contradictory effects of stress and how it can contribute to the dynamics of conflicts.