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How the mind develops

From Embryo to Ethics

Help Link : Aile Piaget Link : Périodes de development Link : Jouer pour le cerveau
Link : The baby's brain Link : The child brain Link : The teenage brain Link : The adult brain
Link : The aging brain Link : The Nervous System in Old Age Link : Non, tout ne se joue pas avant trois ans !
Research : Jean Piaget (1896-1980) Chercheur : Piaget’s Theory of Cognitive Development
Original modules
Tool Module: Darwin's Natural Selection Darwin's Natural Selection

Individuals seems to develop their knowledge in a similar manner to scientists in general: on the basis of a particular level of knowledge, or “paradigm”, they make a transition to another level that lets them grasp reality more accurately.

Thus, a small child does not look at the world the way an adult does, any more than the people in the Middle Ages who believed the world was flat saw the world in the same way that scientists do today.

Because people cannot remember their births or the first few years of their lives, you might think we were all amnesic at those times. But that is neither true nor false. Babies do in fact have memories, because they so effectively remember everything they learn during those decisive years, such as how to walk and talk. We also know that babies only a few months old show more interest in a picture that they have never seen before than in one that they saw yesterday—proof that they have the latter stored somewhere in their memories.

But babies retain only scattered impressions of their experiences, because not all of their brain circuits are complete at birth. The development of the axons, in particular, is still incomplete, and they do not yet interconnect the various parts of the brain effectively. Because a coherent memory requires simultaneous contributions from very diverse regions of the brain, babies memories’ are therefore still fragmentary.


From birth until death, human beings continue to change as they go through the various stages of their lives—infancy (the first month of life), babyhood (until about age 2), early childhood (until age 5 to 7), childhood (until age 11 or 12), pre-adolescence (until age 13 or 14), adolescence (until age 17 to 20), adulthood (until age 60 to 70), and then old age.

Intuitively, we perceive each of these somewhat arbitrary divisions as a major stage in our lives, but some researchers have tried to determine whether they do in fact correspond to actual stages in the development of our intellectual faculties.

Swiss psychologist Jean Piaget (1896-1980) was one of the first people to examine this question systematically. His pioneering role in developmental psychology has often been compared to Darwin’s pioneering role in our understanding of the development of species, which is no small compliment.

But whereas Darwin had to sail around the world for five years to accumulate his data, Piaget began gathering his in his own home, by studying his own children! He thus became the first to show that children are not less intelligent than adults, but simply reason in a different manner.

How do these early modes of thought evolve as the child grows to adulthood? That is the question that occupied Piaget for a large part of his life. And the basic answer he provided is that thought develops in stages. Whenever a developing individual reaches a new stage, it results in the rebuilding of the entire edifice of knowledge that he or she had acquired up to that point.

From his experiments, Piaget deduced that there are four main stages of development, each of which comprises several subdivisions.

It is not just the data that Piaget gathered that made him famous, but also his “clinical method”. In this approach, which Piaget pioneered, the experimenter plays a father-like role in semi-structured conversations with the child.

Still used today in various forms, this approach focuses not so much on the child’s answers as on the reasoning that underlies them. When children gave incorrect answers, Piaget found that they always provided far more insight into the workings of the children’s mind than correct answers would have.

Here is an example of a typical dialogue, between Piaget and a 5-year-old girl named Julia.

Piaget: What makes the wind?

Julia: The trees.

P: How do you know?

J: I saw them moving their branches.

P: How does that make the wind?

J: Like this (waving her hands in front of her face). Only the branches are bigger. And there are lots of trees.

P: What makes the wind on the ocean?

J: It blows there from the land. No. It’s the waves…

From this discussion, Piaget concluded that though this little girl’s beliefs about the wind were false, they were completely consistent within the framework of her young thought system.


Link : Jean Piaget - The Three Mountains

In one type of conservation-of-number experiment, the experimenter shows a child two rows of marbles that are equal in number but one of which is more widely spaced, then asks the child whether the number of marbles in the two rows is the same. Children as young as 3 can give the correct answer. In Piaget’s version of this experiment, however, he asked the same question twice: first with the two rows spaced the same, and then spaced differently. Only older children could tell that the number of marbles was still the same. The reason may have been that because the children were asked the same question twice, the younger ones felt that a different, negative, answer must have been expected the second time.


Piaget’s historical contribution to developmental psychology is considerable. His greatest achievement may well have been his having introduced the empirical study of the psychological development of children, a practice that was almost completely new in the 1940s.

Most developmental psychologists today no longer accept all aspects of Piaget’s theories as he proposed them. As often happens in science, his pioneering studies have now been subjected to numerous criticisms that have highlighted their limitations.

Many of these criticisms concern his research methods. Piaget studied his own children and the children of his colleagues in Geneva in order to deduce general principles about the intellectual development of all children. Not only was his sample very small, but it was composed solely of European children from families of high socio-economic status. That is why many scholars have questioned the representativity and even the reliability of his data—not only because of his limited number of subjects, but also for having neglected individual differences.

Other critics say that Piaget’s experiments were designed more to trap children than to try to see just how far their reasoning could take them if they were given enough information. Indeed, many, more recent studies have shown that young children actually have greater cognitive abilities, at least under certain conditions, than were reported in Piaget’s studies (see sidebar).

Some doubts have also been raised about how children understood the words that Piaget used in the questions that he asked them. For example, does “more” or “the same thing” have exactly the same meaning to a child as it does to you?

Lastly, some critics argue that Piaget greatly underestimated the value of social learning, the kind that comes from parents or, later in life, from teachers.


Link : A-B-C d'une bricoleuse Link : Éthologie Link : Konrad Lorenz : A propos de l'empreinte Link : La théorie de l'empreinte mène à l'attachement
Link : IMPRINTING Simulation Link : Imprinting : A brief description
Research : Konrad Lorenz - Autobiography Research : Konrad Lorenz Research : Konrad Lorenz : Biographie en résumé

The idea that we can have innate behaviours that are already adapted to the world into which we are born may seem surprising until we recall the long process of evolution that resulted in the brains we have now. Anyone who has watched animals being born and is the least bit observant can testify to the evidence of numerous instinctive behaviours.

Such behaviours are “pre-wired” into the nervous system long before the animals have had any memorable experiences. These behaviours and their neurological substrate have probably evolved to improve the newborns’ chances of surviving in a world fraught with predictable perils and difficulties.

The innate behaviours of birds provide an especially eloquent example of this phenomenon. Just consider, for instance, the complex sequence of movements that chicks must execute in order to emerge from their eggs.


The neural circuits in the human brain are determined both by genetic instructions and by experiences encountered in the environment. But the environment’s influence on the brain varies greatly with a person’s age. For example, the environment has a far greater impact on the nervous system of a newborn than on that of an adult.

In fact, during certain early periods of life, the neural pathways are highly sensitive to environmental influences, and a veritable remodelling of the brain is possible. These intervals of time are known as critical periods.

One of the first examples of a critical period to be studied was the period when young birds are susceptible to imprinting, a form of learning first described by Konrad Lorenz, one of the fathers of the science of ethology.

In the mid-1930s, Lorenz observed that just after birth, greylag goslings quickly become attached to the first large object that moves in front of them. Most of the time, this is their mother. But if their mother is not there, the goslings will form this attachment with any moving object of sufficient size and follow it around as if it were their mother. In Lorenz’s experiments, the objects in question were his own wading boots!

This imprint is acquired very rapidly and, once acquired, generally never goes away. (Indeed, Lorenz chose the term “imprint” to suggest the permanence of the trace thus left in the young animals’ brains.) An imprint can form only during a limited period of time (in the goslings’ case, no more than two days after the eggs have hatched), which is why the term “critical period ” is used to describe this decisive phase in social attachment.

In human beings, the acquisition of language seems to be subject to a critical period that starts at birth and ends at puberty. People who have not been exposed to any language before puberty seem unable to learn one after that. Learning a second language is also far easier before adulthood.

Though certain periods in our early lives are critical for the smooth development of our perceptual and social skills, experiences later in life still influence our brains through our learning processes.

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