It may seem as if it could go on an infinite number of times. But can mirrors facing each other really create infinite reflections? In theory, yes — but the imperfections in mirrors make it ...

For her gym, that meant keeping massive fitness mirrors out. Experiencing negative feelings while staring at your reflection in the gym could be explained by something called the theory of ...

You probably didn’t but you will now. Put your fingernail against the glass. If the mirror is real, you’ll see a space between your fingernail and the reflection. No space? Smile and wave.

If I am an infant and I cry but no one comes to my aid—or worse, someone yells at me or hits me—I am left without a mirror to understand my behavior. Without this reflection, I am unable to ...