With regard to historical developments, one question keeps coming up: are the trends in this or that behavior, situation, phenomenon, etc. decreasing, increasing or remaining stable?
This immediately raises the question of the validity of the measurement of the phenomenon: is it actually increasing, or is it just because it is more often detected? Is it actually decreasing, or is it just because we do not pay attention to it anymore?
One of the variables to be controlled in order to know if a phenomenon is stable, increasing or decreasing is, of course, demography: generally, we can say that the number of children and teenagers in France has been stable for 30 years, in a context of strong aging of the population, as the following data shows:
– all ages:- 1992: 58 million;- 2019: 67 million (increase of 14%);
– between 0 and 19 years old:- 1992: 15.5 million;- 2019: 15.4 million (increase of 0%, in fact a decrease);
– 65 years and older:- 1992: 8.2 million;- 2019: 13.1 million (increase of 60%).
The population concerned: how many young people are there?
Schematically, there are 800,000 young French people per age group (12 million children, 4 million adolescents, 4 million young adults). Compared to the birth rate of the 30 years following the end of World War II, there was a certain drop in birth rate in the 1990s, which explains the lower number of 15–24-year-old cohorts today, but we can see how the birth rate has increased since 20003.
October 2021
1 1 For other actors, another version is that psychology is only neuroscience today.
2 2 Neuroscience or the death of the small horse of psychology.
3 3 A more vigorous parentality policy in France compared with that of our neighbors, is often cited as a factor in this phenomenon.
1
Interdisciplinary Themes
Before addressing the evolution of knowledge in each area of child development, we thought it would be useful to point out the major themes that run through our discipline and guide the work in various fields.
1.1. The question of prediction
Behavioral genetics, like psychoanalysis, looks for causality in the child’s past in different ways, but can we predict the child?
The retrospective approach can even prescribe, because by predicting too much, we end up creating “fate neuroses”, with prophecies ending up realizing an unfavorable future for the child.
1.1.1. Prediction before birth
1.1.1.1. “To be born or not to be born”, “Not to be born at all is best..." (chorus of Oedipus at Colonus)
Using prenatal diagnoses, doctors and parents can now predict the appearance of diseases and deficiencies (trisomy, cystic fibrosis, etc.); it is even more complex for the birth of a second child when the first child has one of these types of hereditary disease. We can see the risks of eugenics.
Even in the case of normal development, the choice of a child’s sex has led to disparities in some countries. Are we going to go as far as selective pairing of parents based on their DNA?
Two strategies are currently available to parents in the case of a proven hereditary risk: to modify the embryo through biotechnology or to medically terminate the pregnancy. Both can pose moral or ethical dilemmas for the parents. This theme will be taken up again in Chapter 2, on the fetus.
1.1.1.2. Predicting adult problems from childhood
The links between behavioral problems in children and problems in adulthood are well known and affect almost all areas of life. Various mechanisms may be at work:
– the continuity of a trait from childhood to adult life (the anxious child becomes an anxious adult);
– childhood problems and adult problems may be linked because they share the same risk factors (such as poverty and violence).
1.2. Development concepts
Two major development models have always been in conflict: development in stages and continuum development.
In the stage model (Piaget, Freud), the development of the child’s intelligence or sexuality proceeds in chronological stages, from an initial state to a final state, each stage building on the previous one.
In the continuum model (Wallon, Zazzo), the stages exist only in the mind of the observer, but the development for the subject himself proceeds progressively, from birth to death.
Does this “continuum or stages” debate still make sense? Piaget’s stages, or “staircase” model, from the first sensorimotor intelligence step to the final abstract intelligence step, is challenged today, especially in the work on newborns. In this book, we will see that some acquisitions are much earlier than Piaget thought and that the development of intelligence is not linear.
Another more recent model is Siegler’s “waves” model: the newborn has various cognitive strategies at his disposal from birth that compete to understand the world; he therefore launches them like overlapping waves to arrive on the shore of understanding. With experience, and depending on the situation, the child will use one strategy or another.
We can also evoke the progressive stabilization of synapses, learning by loss, by inhibition or Bachelard’s “philosophy of no”; the child’s neurocognitive development takes place through a multiplication and then pruning of the connections between neurons, hence a reduction in the brain’s gray matter. This pruning has been described by Changeux (1983) as a selective stabilization of synapses by a “neural Darwinism” mechanism; this maturation takes place in successive waves according to the areas of the brain: first, the regions associated with basic sensory and motor functions, then, up to the end of adolescence, the regions associated with higher cognitive control (notably, inhibitory control). The child also learns to inhibit strategies through experience, imitation or instruction from others.
This leads to a nonlinear development model made up of learning curves revealing explosions, collapses and turbulence.
Functional magnetic resonance imaging (fMRI) allows the visualization of brain dynamics corresponding to the activation/inhibition
