You don’t have to be a cat person to feel your heart warm up at the sight of a big-eyed, tiny-nosed kitten stumbling across the floor. When confronted with a baby kitty, you may feel the urge to scoop it up and cuddle with it for the rest of the day. This reaction isn’t limited to felines—puppies and even some adult animals trigger these same snuggle instincts. If this feeling sounds familiar, that means your brain is just doing what it evolved to do to preserve the human species.

This episode of the National Geographic video series We’re Wired That Way lays out what's going on in your head when you see something cute. The facial features of most young mammals fall into the same configuration: large round eyes, and small noses, mouths, and chins. This is called kinderschema, and humans are engineered to find it adorable because it can be found in our own babies. When we see a typical baby face, it activates our instincts to nurture and protect while also releasing the feel-good chemical dopamine to reward us for doing so. That way we feel driven to keep babies safe even if they’re not our own, thus boosting their chances of survival and the survival of our species.

Because kinderschema isn’t limited to the human race, we feel this response when looking at non-human baby animals as well. Some mammals, like cats and guinea pigs, retain their kinderschema into adulthood. So next time you let out an involuntary squee at the sight of your pet, remember that you have biology to blame.

[h/t National Geographic]