Social contagion refers to the phenomenon where behaviors, emotions, or ideas spread among individuals within a group, similar to the way a virus spreads. This can occur through direct interactions or through social media, where people may adopt trends, attitudes, or feelings based on what they observe in others. Factors such as peer influence, social networks, and cultural norms play a significant role in social contagion. For example, if a person sees their friends expressing excitement about a new movie, they may feel compelled to watch it as well, illustrating how collective behavior can shape individual choices.