In the past, when the subject of child development was mentioned, it always referred to cognitive (intellectual) and motor development, but today there is also considerable interest in the development of social-emotional skills. The marshmallow test is often cited as one demonstration of social-emotional skills. In this psychological test of self-control, children are shown marshmallows and told that they will receive an extra one if they can exercise the willpower to resist eating them for a certain period of time. The results were quite astounding as Dr. Walter Mischel, the psychologist who developed the marshmallow tests, found that ten years later, the development of children who had been able to exercise self-control and put off eating the marshmallows was higher overall than those who had not.

Among specialists in education today, this question of how to enhance social and emotional skills of children is enthusiastically studied today.

As a pediatrician, I have experienced a number of situations that demonstrate individual differences in emotional control including self-control, which I would like to introduce here.

I am referring to what takes place when giving children injections. No one wishes to cause children pain, but for pediatricians, it is necessary to give painful injections for tests or treatment, and this always presents a dilemma. When I was younger, I would often give the usual assurances that the injection would not hurt or that it would only sting a little, just like an ant bite. However, after some time, I realized that it wasn't good to mislead the children, so now I tell them "You're going to feel some pain, but you can stand it."

Individual differences in emotional control can be seen in children's reactions when receiving a shot that will hurt. Even when the parent or nurse tries to hold down the arm, children who refuse to get a shot whatsoever will resist with all their strength by twisting and pulling it back. Even toddlers can be difficult to restrain.

However, there are also many children who readily submit to receiving the shot without moving their arm, even though they're crying loudly. In many cases, the mother will also encourage the children by saying "Be good, and it will be over soon." Even when the child cries because of the pain, he or she does not resist receiving the injection.

When children resist the injection with all their strength, mothers will often tell the child "I know it really hurts and you don't like it" or glance at me with seeming disapproval as I give the injection. When the parents are fully convinced about the shot and tell their child that although it will hurt, it is something necessary, they tend to cry loudly, but keep their arm still.

I don't agree with the tendency to blame the mother for everything that has to do with child development. However, it is my conjecture based on experience that a strong parent-child attachment relationship and the mother's understanding of the social circumstances (also a social-emotional skill on the part of the mother) when a shot is necessary for testing or treatment despite some difficulties play an important role in the social and emotional development of the child.