Dear Camren,

I was a very quiet kitten. I only cried when I needed something. But some kittens in my litter cried all the time.

I talked about this with my friend Masha Gartstein. She’s a psychology professor at Washington State University. She studies how babies develop different temperaments. That’s how you relate to the world around you in a way that’s unique and fairly consistent.

Gartstein told me babies cry because they’re helpless. They need a way to signal that they need something.

“Babies are born into this world needing a lot of assistance—and without a lot of communication tools,” she said. “Crying is a very powerful communication tool.”