Things were great at home. Everyone was getting enough sleep, cleaning all the laundry and dishes, and keeping up with homework. So it seemed like the obvious time to upend it all by getting a puppy.

Upend it the puppy did. At 2 a.m., with objects soiled or chewed up dotting the house, chaos reigned. I was about to lose it, and then the puppy did something unbearably cute. Misery evaporated, because the puppy was so adorable that I was going to eat him up, starting with his tiny wittle paws. This, of course, prompted the question: “Why is caregiving behavior being elicited from me by the infantile features of another species?”

Mammalian babies all look the same: short snouts, high foreheads, round faces, big eyes. And we love it. The more a particular baby’s features accentuate those traits, the cuter we rate the face. People, including children, prefer pictures of babies over those of adults, and they prefer cute babies over un-cute ones.

Brain-imaging studies show that looking at baby faces activates dopamine “reward” pathways in the brain: The cuter the baby, the higher the activation. (I’m full of empathy for the parents whose babies are used as examples of “not cute” in these studies.)

Baby features, it is thought, evolved to “release” caregiving behavior in adults—an adaptation that is no news to parents. Researchers have found that pictures of babies make their viewers more precise and careful in fine motor tasks, and make them pay more attention to small details. Poignantly, cuter babies elicit a deeper protective impulse: When subjects were shown pictures of babies and asked to rate their motivation to care for them, they were more inclined to attend to the beguiling beauties.

This helps to explain the evolution of baby cuteness and their parents’ responses. But why have this sort of response to the young of another species? It doesn’t help our evolutionary fitness to get all googly-eyed and have an urge to pay for piano lessons for a baby beluga.

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