As the Apostle saith, "They show that the work of the law is written on their hearts" (Rm 2.15).  From the New York Times, fascinating insights into the moral life of babies:

Not long ago, a team of researchers watched a 1-year-old boy take justice into his own hands. The boy had just seen a puppet show in which one puppet played with a ball while interacting with two other puppets. The center puppet would slide the ball to the puppet on the right, who would pass it back. And the center puppet would slide the ball to the puppet on the left . . . who would run away with it. Then the two puppets on the ends were brought down from the stage and set before the toddler. Each was placed next to a pile of treats. At this point, the toddler was asked to take a treat away from one puppet. Like most children in this situation, the boy took it from the pile of the “naughty” one. But this punishment wasn’t enough — he then leaned over and smacked the puppet in the head.

This incident occurred in one of several psychology studies that I have been involved with at the Infant Cognition Center at Yale University in collaboration with my colleague (and wife), Karen Wynn, who runs the lab, and a graduate student, Kiley Hamlin, who is the lead author of the studies. We are one of a handful of research teams around the world exploring the moral life of babies...

...

In 1762, Jean-Jacques Rousseau called the baby “a perfect idiot,” and in 1890 William James famously described a baby’s mental life as “one great blooming, buzzing confusion.” A sympathetic parent might see the spark of consciousness in a baby’s large eyes and eagerly accept the popular claim that babies are wonderful learners, but it is hard to avoid the impression that they begin as ignorant as bread loaves. Many developmental psychologists will tell you that the ignorance of human babies extends well into childhood. For many years the conventional view was that young humans take a surprisingly long time to learn basic facts about the physical world (like that objects continue to exist once they are out of sight) and basic facts about people (like that they have beliefs and desires and goals) — let alone how long it takes them to learn about morality.

I am admittedly biased, but I think one of the great discoveries in modern psychology is that this view of babies is mistaken.

Here's the whole thing.