As parents throughout time and all over the world have witnessed, when babies are freaking out, they can seem to calm instantaneously when they're picked up. It makes you feel like a hero, but how does it work? Why does your baby stop crying when you pick them up? According to Japanese researchers, the answer is pretty amazing.
In a study by the AIKEN Institute, published by the journal, Current Biology, babies have an immediate reaction to being picked up and held. Measured with electro-encephalogram and by monitoring babies' blood pressure, respirations, and heart rate, researchers noted a stark, perceivable difference in babies' readings as soon as they're lifted from where they lie. Their heart rate decreases, their brain registers a deep calm, and their breathing normalizes. If you think about it, you can hear it happening when you pick them up. Your baby probably goes from full screams to hiccups in a matter of moments. They start to breathe differently, and their little bodies go lax in your arms, all tucked up and cozy. My son would go from full "my basketball team just lost the playoffs" sobbing to "plot twist on Downton Abbey" gentle tears in a heartbeat.
The study showed that this is all evolution. You know that instant draw you have when you hear your baby cry that screams in your head, "pick her up, pick her up?" That's a programmed response conditioned into you by the wails of your child.
The infant response is designed to make them lighter. OK, not literally, but according to the study, it makes it less burdensome to pick them up. They need you to hold them so that you can bond with one another, and evolution provides the way. By noticing that response, the parent is rewarded, making the weight of carrying and caring for this tiny screamer less of a burden.
They scream and then calm down so that you carry them, and they calm so quickly that you don't notice it as much. "As much" is the key phrase here. Evolution doesn't make it easy, it just makes it less noticeably awful. So pick up your baby and enjoy knowing that those snuggles really do make them (and you) feel better.