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How are Developments in Neurobiology Changing our View of Children? 2 Human Intelligence Develops in Prefrontal Association Cortex

Dialogue between Noboru Kobayashi and Toshiyuki Sawaguchi

2 Human Intelligence Develops in Prefrontal Association Cortex

Kobayashi: What is the most important issue in neurobiological science today?

Sawaguchi: We know from recent studies that the prefrontal association cortex is responsible for the highest functions of the brain. Proper development of this area is absolutely critical. The prefrontal association cortex functions as meta-level intelligence that integrates various basic types of human intelligence such as linguistic, logical, mathematical, visual, and musical intelligence. It is similar to a baseball manager who is constantly thinking about which player to use next and watching the opposite team and how the game is going.

The prefrontal association cortex of chimpanzees is only one-sixth the size of a human's. In terms of evolution, the chimpanzee brain is said to be the closest to a human brain, but even so, the prefrontal association cortex is much smaller in proportion. In other words, the prefrontal association cortex is what makes Homosapiens act human.

The formation of the family unit about three million years ago is thought to be one reason for this development of the prefrontal association cortex in humans. About this time, the differences between males and females decreased and something similar to the family unit that we have today was formed although it was polygamous. A society consisted of about twenty groups of people that were each made up of five or six people. It is thought that the family relationships and social relationships between families in this type of society promoted the development of the prefrontal association cortex.

Kobayashi: What kind of education does the most to stimulate the prefrontal association cortex?

Sawaguchi: It amounts to letting children play (laughter). It sounds banal, but to be specific, this means giving children the opportunity to have a wide variety of social relationships and experiences. And this should be done before children reach the age of eight, while they are in a sensitive period and the brain is undergoing drastic change.

Earlier, in your definition of Kodomogaku, you stated that children who start out as biological beings become social beings. I totally agree, but in neurobiology and evolutionary biology, the process of becoming a social existence is a biological program and is thought to the result of a mechanism that starts operating in childhood. This means that social interaction is necessary from childhood.

Kobayashi: When children are born, for instance, there is the mother and child, and then the father and it becomes a triangular relationship. The relationships increase with the number of siblings and grandparents. Don't these changes in family relationships affect the development of the prefrontal association cortex?

Sawaguchi: Well, to tell the truth, I haven't thought much about the stages of socialization. I was simply thinking that it is preferable for there to be a lot of people around from the time a child is born. But, reading your book really opened my eyes. As you point out, it starts with a good mother-child relationship and then extends to the family members such as the father, siblings, and grandparents and so on. Actually, this sort of family environment has disappeared.

Kobayashi: In that case, do you mean that in addition to the family environment, we should create an environment where children can play freely with one another?

Sawaguchi: The important thing is that they have deep human relationships rather than a lot of friends. They need to experience complex social relationships that are meaningful because they are made up of seemingly negative interactions like bullying, fighting, troubles and complications along with positive interactions like friendships, helping others, cooperating, and sharing joys and sadness. They need deep human relationships that are nurtured by physical contact.

Kobayashi: I couldn't agree with you more. Human relationships that are not controlled, but spontaneous are always meaningful for children.


Pediatrician and Director, CRN
Born in Tokyo in 1927. Doctor of Medicine, Faculty of Medicine, The University of Tokyo, 1954. Books include Human Science, Kodomo wa mirai de aru (Children are Our Future), Kodomogaku, Sodatsu sodateru fureai no kosodate (Reciprocal Development Through Child-raising).

Toshiyuki SAWAGUCHI, Ph.D.
Professor of Neurobiology, Hokkaido University School of Medicine
Born in Tokyo in 1959. Majored in biology, Faculty of Science, Hokkaido University. Doctor of Science, Kyoto University. Specializes in cognitive neuroscience and primatology. Research interests include mechanisms within the brain related to thought and self and evolution of the brain and cognitive function. Publications include Wagamama na no (The Selfish Brain), Watakushi wa no no doko ni iru no ka? (Where is the Self in the Brain?), and Yoji kyoiku to no (Early Childhood Education and the Brain)."
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