Secret Garden

She stirred and my mother narrated this to us matter-of-factly, as told to her by my grandma.

When babies sleep, they go to this garden in their dreams where they'll meet other babies (who presumably are also napping).
So that explains why they sometimes laugh to themselves or bawl out loud while still in slumber. It depends on whether they're having fun or being bullied by the other tots.

Now how does one go abt debunking that?