American babies do, however, have the Dutch beat when it comes to being noisy, researchers say.

They were found to be more vocal and active than those in the Netherlands; they also showed more fear, sadness, and frustration, while Dutch babies were easier to calm down.

The findings were based on surveys of mothers that asked about the occurrence of 191 different baby behaviors at six months and one year of age.

Why the differences? Researchers have some ideas.