Jean-Pascal Assailly - Child Psychology

We can thus be led to the paradox that differences in the way parents treat each child are attributable to aspects of family life that are shared by all children. Finally, differential parental treatment is not necessarily pathogenic: it all depends on whether it is experienced by the child as fair or unfair. For example, the child accepts it when the differential treatment depends on the age or special needs of his or her siblings.

From this framework, two types of work can be conducted. On the one hand, “child-based” studies: the child’s genes are the unit of measure and do not directly influence the way the parents treat them, but indirectly, through the parents’ reaction to the child’s characteristics; for example, siblings are compared with each other. On the other hand, the rarer “adult-based” work: the parent’s genes are the unit of measure and we study the role played by genetic proximity on parental behavior, for example, the behavior of mothers who are twins.

We will therefore define:

– genotype/environment interaction: genetic factors influence sensitivity to an environment. For example, divorce has more negative effects on children with a genetic vulnerability to depression; negative life events are a non-shared environmental factor that explains the differences between monozygotic twins in the occurrence of depression. Overly coercive family discipline is a risk factor for adolescent depression, but only in certain social settings;

– genotype/environment correlation: genetic factors select or cause exposure to different environments. For example, a child’s physical attractiveness causes positive reactions in parents, educators or peers.

Three types of correlations between genotype and environment are therefore distinguished. These types correspond to three mechanisms by which the genetically influenced characteristics of an individual affect his or her experiences:

– passive correlation: parents and children share the same genotype and the same environment. For example, parents pass on genes related to a difficult trait and express this difficult trait through irritable and negative parenting behavior, which in turn is related to the child’s difficult trait. In a child-based construct, this correlation would be categorized as “shared environment influence”, whereas in a parent-based construct, it would be categorized as “genetic factor influence”;

– evocative or reactive correlation: this results from a reaction of the environment to a characteristic of the child under the influence of genetic factors. Parents react to the child’s difficult character with harsh and negative parenting, a “coercion cycle”; a happy child provokes different reactions from a gloomy child, for example. There is a growing acceptance of the idea that children influence how they are treated by others, including their parents, and that parents react differently depending on the child. Adoption studies are the most relevant in highlighting evocative correlations, as they provide information about the biological parents. For example, if we know the psychopathology or addiction of the biological parents, then we can see how it increases the risk of such problems in the adopted child, problems that will in turn influence the parenting behavior of the adoptive parents;

– active correlation: the child actively selects environments that are correlated with his or her genetic characteristics (this is more often true for peers than for parents) or that his or her perceptions of events are genetically influenced (a suspicious child will generally perceive his or her parents’ behavior more negatively than a confident child and will act accordingly; a depressed adolescent will isolate himself or herself and inhibit influences from his or her parents).

We must understand all these processes that build parental behavior and its adaptation to the child if we want to be able to improve dysfunctions and their consequences.

The vast majority of research in the field of developmental psychology suffers from a strong sampling bias: 91% of the studies focus on children in wealthy, industrialized, democratic Western societies; moreover, even in these societies, children from the middle and upper classes are overrepresented 1.

Work in anthropology and cross-cultural psychology allows us to overcome these knowledge limitations through two approaches: a depth or precision approach, which often relies on detailed and deeply contextualized ethnographic data, typically from one society, and a breadth or size approach, which relies more on experimental data from standardized tasks deployed in many different societies. These two approaches are complementary, each with its own strengths and weaknesses (see Amir and McAuliffe (2020)).

Like other primates, young humans are dependent on others for long periods after weaning and exhibit a unique life history stage called infancy. Follow-up fossil evidence such as the eruption of the first, second and third molars suggests that the duration of this stage of life history has more than doubled over the past 4 million years.

This lengthening and dependence are at the heart of hominization 2, the concept of “neoteny” describes this immaturity at birth of the human baby compared to other species, but it is precisely this immaturity that will allow the development of specifically human characteristics. For example, the infant chimpanzee dominates the infant human in the first months of life in all types of tasks and tests, then progressively, this ratio will reverse.

The length of childhood will allow the human child to acquire an enormous amount of information, directly through its own observations and actions, as well as indirectly through a complex cultural transmission. Moreover, human populations, having colonized the entire planet, live in very different geographical, climatic and social environments, hence the concept of “adaptive phenotypic plasticity” which describes the capacity of an organism to adapt its development to environmental conditions (Amir and McAuliffe 2020).

Adaptation for the individual will consist of developing phenotypes that are suitable to environmental conditions from the start of life; variations in behaviors will result from the responses to the different socioecological indices.

An empirical and developmental example of this type of prediction is that a child’s neighborhood hardship enables his or her prosocial behavior to be predicted in an experimental game: children living in difficult, low-income neighborhoods exhibit less prosocial behavior toward strangers than children in less difficult, higher-income neighborhoods. These patterns mirror those observed among adults living in similar economic conditions (Safra and Tecu 2016).

Development during childhood is a period of heightened sensitivity to environmental indices and developmental research in this area tends to exploit variations in these indices as natural experiments to determine downstream behavioral consequences.

A different, but largely compatible, perspective is that derived from “culture-gene coevolution” theory: like adaptive phenotypic plasticity, this approach also offers a rich perspective on child development, but focuses relatively more on the role of cultural transmission in early childhood (Amir and McAuliffe 2020).

This approach draws on the social learning model and focuses on the variation of cultural norms and their internalization as a driving force for behavioral variation across societies; cultural norms are behavioral heuristics that individuals tend to follow when: (1) a sufficiently large number of community members conform to them – the so-called “empirical expectation” (descriptive norms) – and (2) a sufficiently large number of community members expect the individual to conform, also called “normative expectation” (injunctive norms).