Altruism is about helping others even if it costs you something. People can act selflessly for different reasons, like wanting to look good to others or feeling proud or ashamed. Some acts of kindness are based on fairness or making sure others see you being good. In experiments, people are often willing to punish those who are not nice, even if it doesn't benefit them directly. This punishment can actually help encourage better behavior in the future. Some researchers think this punishment is not just about being nice, but also gives a good feeling inside. The idea of helping others has been around for a long time, with many famous thinkers talking about it.