intelligence is one of the most recurrent themes in Psychology and Mind . In addition to having a whole section dedicated to various monographs, research and theories on intelligence, today we echo a particularly interesting subject.

Intelligence: is it inherited… from the mother?

People who are lucky enough to be smarter than average should start thanking someone else in particular: their mothers. Research has highlighted that it seems that mothers carry the greatest part of the genetic burden related to cognitive skills .

This would disprove many of the gender prejudices that are still quite ingrained in our societies and that have been cruelly accompanying women in particular for centuries. According to this information, the intelligence of the parent would not be a strong factor in predicting the intelligence of the children.

Conditioned Genes, the Key to Everything

The scientific basis of this issue lies precisely in the existence of “conditioned genes”. These genetic components, as described by biologists who have studied them in depth, behave differently depending on whether they come from a male or female body.

Apparently, these genes contain something like a biochemical label that provides information about where they come from , and even reveals to us whether or not these genes will be active in the child’s cells. In particular, some conditioned genes are only activated if they come from the mother. If this same gene is inherited from the father, it is not activated. As would be expected, there are other genes that work in reverse: that is, they are only activated if they come from the father.

X chromosome, essential in the development of cognitive potential

It is well known that intelligence is inherited from parents to children, but until recently there was no evidence that this ability was due in greater measure to one of the two parents. The different studies that have revealed that children have a greater probability of inheriting intelligence from the mother point out that the genes related to cognitive abilities are located on the X chromosome .

In fact, the data that support this thesis come from far away. In 1984, a study at the University of Cambridge already detected the trend. The team of researchers analysed certain biochemical and genetic components of the brain, and came to the conclusion that the mother’s genes provide more information for the development of the brain structures associated with thought and mental operations.

To arrive at this surprising finding, researchers worked with mouse embryos modified to reproduce only the genes of either the mother or the father. However, when the scientists moved the embryos into the uterus of a female mouse so that they could continue to develop, they died.

In this way, the researchers realized that there are conditioned genes that only activate when inherited through the mother, and that are indispensable for the development and survival of the embryo. With embryos that were genetic copies of the parents, something different was happening: their genes were crucial for the growth of the placental tissues. They also died.

The hypothesis was clear: if these particular genes were so highly essential to the development (and survival) of the embryo, it would be reasonable to think that they would be genes with great responsibilities for the organic functioning of animals and humans, and perhaps they could be strongly related to certain brain functions. A hypothesis that, after successive studies isolating variables, was validated.

Mice with Amazingly Large Heads

Mice with a higher proportion of maternal genes developed an abnormally large brain, yet their bodies were very small. In contrast, the mice with paternal genes had a tiny head and an overdeveloped body.

As the scientists detected which genes were from the mother and which from the father, they identified several cells that only contained maternal or paternal genes in different brain areas that govern different cognitive functions and processes, such as intelligence or memory.

The scientists did not find any parental cells in the cerebral cortex, where the structures that allow us to have complex cognitive functions, such as intelligence, decision-making, language and other skills, are located.

New research and evidence

Over the years, the scientific community has been reviewing this curious genetic phenomenon. In fact, one of the most renowned researchers in the field of intelligence, Robert Lehrke, revealed that most of the intellectual capacity of newborns is generated on the X chromosome. He was even able to show that women are twice as likely to inherit intelligence-linked traits , by having twice that same ‘X’ chromosome.

A few months ago, another study from the German University of Ulm found that the genetic material involved in brain damage is closely linked to the X chromosome. Furthermore, they pointed out that one of the evidences of this is the fact that mental and intellectual disabilities are 30% more frequent in men.

IQ predictor

All the previous studies are very interesting and give specific clues to the relationship between the mother’s genes and intelligence. However, one of the most revealing studies is the longitudinal analysis carried out in the M edical Research Council Social and Public Health Sciences Unit of the USA.

Over a long period of time, 12,000 young people between the ages of 13 and 22 were interviewed annually. Analysing different variables about the individuals, such as skin colour or sociocultural and economic level, they discovered that the indicator that best predicted the intelligence of each subject was their mother’s IQ .

Beyond genetics

But it is not only genetics that gives us data on this issue. There is other research that shows that the mother plays a fundamental role in the intellectual and cognitive development of her children, through day-to-day stimuli. Several studies suggest that , that pristine bond of trust with the mother, is closely related to future intelligence.

Attachment and its importance for the development of intelligence

Several investigations at the University of North Carolina, among many others, found that children who successfully develop a secure attachment to their mothers are able to carry out more complex symbolic play . In addition, they are more consistent and have a greater tolerance for frustration.

It seems that secure attachment provides the foundation for children to grow up confident in their abilities, facing the challenges of working and solving the problems of their day-to-day lives. It is also remarkable that mothers who provide this secure attachment are also those who stimulate their children more and better so that they can advance in their cognitive development.

What percentage of intelligence is inherited?

But is intelligence really inherited? In what proportion is it so? It is often said that between 45 and 55% of intelligence is written in the genes . This suggests that there is also a significant part, approximately half, that develops if the family, social and personal conditions are good.

It is important to remember that intelligence is nothing other than the capacity that we human beings have to solve problems. There is no specific area of the brain in charge of solving problems, but it is our whole brain that works globally to address any task that requires an effort of our cognitive skills. Moreover, to make matters worse, we not only use rational thinking for these purposes, but also heuristic thinking, intuition and emotions, which are usually more related to the genetic heritage of the parent.

Stimulating the child’s intelligence

You don’t have to pay undue attention to a child’s IQ. Intelligence is an extremely complex construct, which develops if the child’s mind is properly stimulated, with challenges and tasks that, little by little, force the child to scale up his or her cognitive development stages.

As parents, we must be able to understand that we can contribute a lot to our children maturing and developing more complex cognitive skills, and this must be done, let’s not forget, by attending to the emotional and recreational needs of the little ones in the house. Everything helps.

You may be interested in: “5 tips for nurturing your child with emotional intelligence”

Bibliographic references:

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  • Keverne, E. B.; Surani, M. A. et. Al. (2004) Coadaptation in mother and infant regulated by a paternally expressed imprinted gene. Proc Biol Sci.; 271(1545): 1303-1309.
  • Matas, L.; Arend, R. A. & Sroufe, L. A. (1978) Continuity of adaptation in the second year The relationship between quahty of attachment and later competence. Child Development; 49: 547-556.
  • Prieto, M.D. and Arnaiz, P. (1989). A cognitive approach to the assessment of intelligence skills in Special Education. In M.P. Abarca, (coord.). The evaluation of educational programs. Madrid: Escuela Española.
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