Social contagion

Social contagion is like when one person does or says something and then a bunch of other people around them start to do and say the same thing. For example, let's say you and your friends are playing together and you do a really funny dance. Then one of your friends starts laughing and then another one starts laughing and then another one. Soon all your friends are laughing and doing the same dance with you. That's called social contagion!