I wrote a thing for Aeon:
Laughter and smiles transcend barriers of age, language and culture, and babies know this better than anyone. They don’t speak our language. They don’t share our culture; and they are at least a generation younger than us. All the same, we can easily share a laugh.
Spend any time with a baby and, assuming that they’re fed, clean and warm, they will put most of their effort into stealing your heart. Babies are gleeful, cheerful, charismatic and gregarious – inherent comedic qualities that ensure babies give cats a good run for their money in funny YouTube videos. Yet, while research in cognitive science has long recognised the importance of cuteness in early bonding, very few researchers have dug deeper. Until now. With a renaissance in what I like to call ‘positive psychology for babies’, we are starting to appreciate that smiling and laughter serve an important purpose from birth.
You can read the rest here: Why playing peekaboo with babies is a very serious matter | Aeon Opinions