Humor has always been subjective. Where some people prefer the physical comedy of Jim Carrey, others may find the dry approach of Albert Brooks preferable. Babies, of course, are not big on subtlety.

A psychologist explains the evolutionary and psychological roots of laughter, and what an infant’s giggles teach us about how adults bond. There’s nothing quite like bearing witness to a baby’s first ...

Dr. Mireault is a developmental psychologist at Vermont State University. My son was 14 weeks old when he made his first unmistakable whole-body belly laugh. In the months that followed, his laughter ...

Since 2012, I have been studying laughing babies. The question I am most often asked—frequently accompanied by incredulous laughter—is “Why?” And sometimes, “Wouldn’t it be better to study what makes ...