This Is Your Brain on Puppies

There’s a scientific reason you want to squeeze a cute animal’s little face.

This is my dog. Don’t you just want to squeeze her? (Emojipedia / Katie Martin / The Atlantic)

I have an 11-pound Chihuahua, and I love to smoosh her against my face. I’m not exactly sure what I get out of this ritual, because she doesn’t smell great. Still, I take her up in my hands, bring her toward my head, and make a noise in her side that is like a small scream, but without opening my mouth. Afterward, we look at each other for a moment—she’s suspicious, and I’m slightly embarrassed—before pretending that nothing happened.

I harass my dog in this way constantly. She’s a little loaf of a thing, with big eyes and satellite-dish ears and a teeny snoot, and she is so cute that I have overwhelming urges to, among other things, bite her ears and gently boop her nose. As odd as this all might sound when spelled out—the desire to nibble your pets is usually not discussed in polite company—lots of people share these impulses toward dogs, babies, or other wee things they find excruciatingly adorable. Even if you don’t, you might have experienced secondhand embarrassment for someone who does.

This affliction has a name: “cute aggression.” And for the first time, researchers have begun to map what’s happening in our brains when we decide we want to chomp on a chubby baby leg (in a friendly way!). Their findings, published last week in the journal Frontiers in Behavioral Neuroscience, suggest that experiencing cuteness sends many people on a neurochemical roller coaster, with their minds’ attempts to balance themselves resulting in bizarre, intense displays toward tiny, helpless beings. This over-the-top response might serve an important purpose: to ensure that those of us who experience cute aggression don’t spend so much time cooing at a baby or puppy that we forget to take care of it.

When Katherine Stavropoulos, a professor at the University of California at Riverside, first became aware of a 2015 Yale University behavioral study identifying the phenomenon of cute aggression, she thought that finding its neurological basis might put scientists on a path toward better understanding the brain’s reward centers. “These are very cute things that you might want to approach. You might want to take care of them. You’re having very positive feelings—in fact, so many feelings that you’re overwhelmed by them,” she says. “To me, that sounds like a very, very active reward system.”

Stavropoulos used EEG caps to test brain activity as participants were shown a series of images of puppies and babies with varying levels of cuteness according to the theory of kinderschema, which are the set of traits, such as big eyes and little noses, that human brains seem to be wired to find adorable. After each set of images, participants were asked to fill out a survey that inquired about, among other things, feelings of caretaking. The results were clear, Stavropoulos says: The brain’s emotion and reward systems are both involved, but cute aggression flared up specifically when the reward center was overwhelmed. The puppy’s tiny paws are just too much, on a chemical level.

If babies could take care of themselves, it wouldn’t matter so much that adults often experience paralyzing reactions to how adorable they are. Because babies are dependent on us for their well-being, though, it’s important on an evolutionary level that we’re able to snap out of it. That’s where cute aggression seems to come in. The surveys filled out by participants showed that the reaction was also heavily linked to feeling a caretaking urge toward a cute thing. That may indicate cute aggression is our brain’s attempt to balance an overwhelmed neurological response. “A baby can’t survive alone, but if you’re so overwhelmed by how cute it is and how much you love it, then you can’t take care of it, and that baby won’t survive,” she says.

Oriana Aragón, a Clemson University researcher and the author of the 2015 Yale study that first identified the phenomenon, agrees that emotional balance is a potential cause of “dimorphous expression,” which is any emotional response that can present in two distinct ways. “When people express this way, they seem to come down off that intense event,” she says. “Their intensity seems to drop faster than people who aren’t doing cute aggression.” The more quickly a caretaker returns to a state of emotional stability, the better the odds that a small, vulnerable thing won’t experience a significant lapse in having its needs met. If that means I need to smoosh my dog against my face, so be it.

On a behavioral front, Aragón says that there are also some other potential explanations for cute aggression. “The appetitive side of the reward system is about that forward momentum, the antsy feeling, the pursuit, the urge,” she told me. “So it could be that when we see this aggressive expression, it’s an expression of that urge. It’s showing that you want to get to the baby.” The clenched-jaw, clenched-fist look of cute aggression is warning everyone that you intend to squeeze the small, cute thing.

In situations where it might be frowned upon to grab a baby that’s not yours, Aragón and her team found a different kind of dimorphous expression: a cute sadness, of sorts. “The ‘aww’ expression, with a downward-turned mouth and crumpled face, sends a signal to the baby and the other people that you just want to regard the baby, savor the baby, and take that baby in,” she says. The same process happens with other reward stimuli, like a good meal: At first, you anticipate it and you dive into your food, and then you sit back, slow down, and savor.

According to Aragón, cute aggression is only the tip of the iceberg when it comes to understanding dimorphous expression, which occurs in a variety of scenarios, such as when someone is awed by the beauty of nature or overwhelmed by the thrill of victory. “Disgust and pain seem to have special properties about pulling away from the stimulus, whereas tears seem to be about stopping to savor, and aggression seems to be about the urge of pursuit,” she says. Research on emotion expression has historically been that of one-to-one correlations, Aragón says, so dimorphous expression represents a new phase in understanding how we socially negotiate our feelings.

Knowing how human brains generate these responses could have therapeutic potential, according to Stavropoulos, whose work frequently centers on people with autism. “There’s a lot of literature about people with autism having service dogs with huge success, or having horses they really connect with that help them understand the social world,” she says. “Maybe they feel the strong caretaking urge but don’t feel overwhelmed, and that’s a strength of theirs.”

Because caretaking is an essential element of human life, mapping the neurological events behind it could also help illuminate other notoriously difficult-to-treat problems, such as postpartum depression. Whatever the future implications, though, at least you now have a scientific explanation for any stray urges you might feel to jiggle a particularly chubby puppy.