ELI5: Explain Like I'm 5

Mirror test

The mirror test is a way to measure if an animal can recognize itself in the mirror. To do the test, researchers put a mark (like a sticker or some paint) on an animal and then put a mirror in front of it. If the animal touches or looks at the mark in the mirror, then it knows that it is looking at itself. This means that it has a sense of "self".