ELI5: Explain Like I'm 5

Mirror stage

The mirror stage is a stage of development that happens in babies when they are around 6 months old. It's when babies first start to recognize themselves in a mirror and think the other baby in the mirror is another person. They promote their physical skills and learn how to copy what the other baby does. It helps the baby identify themselves as separate from their caregivers and understand the world around them better.