Among those who are active in the field of child development, the following is a widespread assumption, something like common sense. At the age of two, children are considered to be undergoing a difficult phase--a time when they are impatient, demanding and self-centered. "Theory of mind," which is the ability to understand the feelings of others, develops between the ages of four and five.

A scene that I once witnessed of a girl who had just turned two years old completely overturned this common sense. It took place at a hall at Doshisha Women's College of Liberal Arts in Kyoto, where the Society of Child Science held a conference last year. In his lecture, Professor Hiroyuki Kasama of the university who is known for his research on sandbox play, showed a video of a child (whom I will call "A-chan") playing in a sandbox from the age of one to six over a period of five years until the completion of kindergarten. The scene was part of his presentation.

A-chan had just turned two years old and was playing in a sandbox when a little incident occurred that would be quite common in any kindergarten or daycare. A boy about the same age as A-chan threw some sand on the head of a boy playing next to him. A nearby childcare worker separated the two children as A-chan watched closely. After the childcare worker left with the boy who had thrown the sand, A-chan approached the boy and started to brush the sand out of his hair.

I was moved to see this expression of empathy in a two-year-old. Dr. Kasama then quietly explained that something even more surprising occurred thirty minutes later.

Thirty minutes after the sand-throwing incident, something wondrous happened in the sandbox. A-chan was standing next to the boy who had thrown the sand earlier. A-chan suddenly approached him, and with her hand, poured some sand on his head, and quietly moved away. The boy was surprised to have sand poured on his head.

A-chan let the child who had poured sand on someone know "this is how it feels to have sand poured on your head." This ability becomes possible when the theory of mind develops at the age of four or five, but it appears that A-chan had already developed it at the age of two. As adults, we think that we understand children, but do we really?

Watching this video, I did not harbor doubts about the theory of mind, which is an intellectual concept of adults. Rather, I was simply moved by the wondrous ability of a child to acquire such a rich sense of empathy at the age of two.