Interview with Josette Serres – Part 1

Josette Serres, hello and thank you for agreeing to this series of interviews. You hold a Ph.D. in developmental psychology, are a former research engineer at the CNRS, and a specialist in neuroscience. You have also written several books and articles, and you have taken a particular interest in the role of social interactions in infants’ cognitive development and language acquisition during the first few months.

In this first interview, I’d like you to give us an introduction to brain immaturity: the baby’s great dependence, but also their remarkable capacity to make sense of the world!

Brain immaturity in young children: what is it, and what are its consequences?

Despite nine months of gestation, the human baby is born very immature and enters the world in a highly vulnerable state. Parents must take turns at the baby’s side to meet its needs, as it could not survive on its own. The baby will also be able to make itself understood. This high level of dependence is characteristic of certain species that protect their young, and this disadvantage will turn into an advantage. The brain will continue to mature after birth and benefit from all the stimulation it receives. Childhood is long because the human brain is very demanding. Its fuel is glucose, and our bodies must make choices between the brain’s gray matter and physical growth.

However, brain maturation is uneven, and certain parts will not be fully functional until the end of adolescence. The parietal, temporal, and occipital lobes are functional at birth, but for the frontal lobe, we’ll have to wait. This important part of our brain is the seat of executive functions: in other words, everything that allows us to control our reasoning by choosing one solution over another, by being able to plan, and by changing strategies if the one implemented isn’t working. The frontal lobe is also responsible for our emotional control. The importance of control in our development is highlighted by the theory of inhibition, which states that a child’s major achievement lies in being able to inhibit inappropriate behaviors (“cold” inhibition) as well as emotional reactions (“hot” inhibition). But this capacity for control takes years to develop!

So can you tell us more about how the brain works?

When a child makes new discoveries, connections form (synapses), some strengthen, others weaken, and some disappear (neuronal pruning). The effectiveness of synapses is therefore influenced by the frequency of information received by the brain. Thus, the child can adapt in response to their environment and prepare for changes. However, we must be wary of an idealistic interpretation. Since synapses form based on frequent experiences, it is possible that these experiences may be harmful, yet our brain will integrate them as important simply because they are frequent!

The brain does not “copy” the world; it tries to predict it. It constantly calculates what must happen based on what has occurred so far, and it is the prediction error that enables learning.

A child’s brain contains our human heritage and tells us where we come from. A child’s reasoning relies on a small set of innate, early-established, and rigid systems of principles. These systems are called “core knowledge” and mark our origins.

Babies’ brains, already endowed at birth with “core knowledge” (Box 1), are also wired for learning. The first years of life are devoted to discovery. These discoveries result from manipulation and experimentation. All of a young child’s new knowledge is acquired through free movement. Children learn by interacting with objects. The brain specializes in managing movement. In a safe environment, babies can explore their surroundings to understand them and enter the world of adults.

You mentioned that babies’ brains are already equipped with “core knowledge” at birth. Could you please give us some examples of this core knowledge?

Recent research has shown that babies possess two systems dedicated to mathematics: one for small numbers up to three and another for numbers beyond that. Babies can mentally represent space, and this serves as the foundation for the development of geometric concepts. They want to understand the world and very early on observe the constraints that limit an object’s movement in space and time.

Two objects cannot occupy the same space at the same time. An object retains its unity, even when partially hidden, and cannot be passed through by another. Infants understand that objects are inanimate and can only move upon sudden contact with another object. This principle does not apply to humans, who are animate beings. Human movements are driven by a purpose or intention. The baby establishes categories and gives preference to people who speak to them in their native language, regardless of skin color or any other characteristics.

 

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