A 2015 study published in Psychological Science delved into this phenomenon. Psychologist Oriana Aragon and her team showed participants pictures of babies whose infantile features, or "baby schema," had been altered to look extra cute (the media and their unrealistic representation of infants, am I right?). Then they rated how much they agreed with statements that began with "When I look at this baby," and ended with things like "I feel like I am overwhelmed by strong positive feelings," "I want to protect it," or "I feel like pinching those cheeks!" on a scale of 1 to 100. Unsurprisingly, the researchers found that the cuter the baby, the more subjects felt overwhelming emotion, a desire to care for it, and—tellingly—expressions of aggression.
Related: Why Are Babies So Cute?
Why is this? A later part of the same experiment gives some clues. They tested the participants before, directly after, and five minutes after seeing cute babies. The people who expressed the most aggression in the moment had the greatest declines in positive feelings five minutes later. Though that might sound like a bad thing, experts have some theories about its evolutionary benefits.