Babies are playing you. We all know that they’re cute, and they tend to make people smile and they make silly sounds and they even smell nice. But why? Well, being cute makes people want to take care of you, which is precisely what human infants need more than pretty much any other species out there. Compared to even our closest primate cousins, humans are incapable of taking care of themselves for quite some time after birth. It’s a byproduct of our being born relatively early so that our huge (comparatively) heads can fit through the birth canal.
Okay, so babies are cute and we like them. But humans evolved to not only be cute to look at, but to smell and hear as well, and interacting with them triggers parts of our brains associated with pleasure, so that we like being around them and taking care of them. And these things don’t just affect parents, but most people, regardless of gender or relationship to a given baby. Sure, there are people who don’t like kids and certainly don’t want any of their own, but most people at least find them cute.
Appealing to their mothers is a common enough thing for babies of many species, but appealing to other members of the species could have been just as important from an evolutionary standpoint. Especially for humans and other social animals, being able to appeal to others in the group could help babies survive in far more difficult times, when their biological parents might not survive. It also means that, if they were off hunting or gathering, they could have safely left their children with other members of the tribe and expect those people to keep their kids alive and well.
So the next time you find yourself distracted by a baby, remember that kid was genetically engineered to be the cutest, most adorable thing possible.