Children Inherit Intelligence Mainly From Their Mothers: How Far Is It True?

Learning from experience, applying and acquiring skills and knowledge, and adapting to changing environments are the characteristics of intelligence. In biology, intelligence is explained in terms of the functioning of the prefrontal cortex (the part of the brain responsible for cognitive functions) and the size of the brain [1]

Also, intelligence tends to change over the course of a person's life and across generations.

Intelligence is influenced by both inherited and environmental influences. According to a study, intelligence is highly heritable, around 20-50 per cent. Meaning, you are likely to get 50 per cent of your intelligence mainly from your parents, and the rest can be influenced by your occupation, education, health and other environmental factors. [2]

If we narrow the inheritance factor of intelligence, we may find that mothers are primarily responsible for the passing of intelligence genes to their children, compared to fathers.

Did you know that a mother's intellectual abilities contribute directly to the development of intelligence in her children, as it is a hereditary and genetic trait? Read more here.

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Genetics Of Intelligence

According to a study published in the journal Genome Research, a plethora of genes present in the X chromosome are responsible for affecting intelligence and cognitive functions. The normal X-linked gene is responsible for the development of IQ and cognitive function, while problems related to mental retardation in the X-gene may tend to decrease IQ. [3]

However, the studies are controversial as there are multiple facets of intelligence.

Is Intelligence Inherited From Mothers?

A study has shown that the intellectual abilities of a mother directly influence the development of intelligence in children, as it is a heritable and genetic-based trait. Though it is also linked to an adult's life outcomes and experiences and the environment at home, maternal intelligence is an important factor in the neurodevelopment of children.

Before moving forward, let's understand the concept of chromosomes. Chromosomes are DNA molecules that contain genetic encoding for an organism. Each cell in the human body contains one pair of chromosomes. Two X chromosomes are found in females, while one X and one Y chromosome are found in males. [4]

Due to the fact that women have two X chromosomes whereas men only have one, women are more likely to pass on intelligence genes to their offspring.

Also, a secure emotional bond between a child and mother may lead to a 10 per cent larger hippocampus at the age of 13, compared to child who lacks such emotional bonds. The hippocampus is a part of the brain involved in memory and learning. [5]

In addition, some researchers say that genes passed down from the father that are associated with advanced cognitive abilities could be turned off automatically. [6]

What Are Conditioned Genes?

Conditioned genes are genes that are carried and transmitted by every member of a population, but remain activated or deactivated based on many factors. Say that these genes are "tagging" genes that have two critical functions: tracing the gene's origin and determining its state (active or deactivated).

If a gene from one parent is activated in a child, it means that they will possess some of their traits, including intelligence. As intelligence is considered to be one of the most conditioned genes passed from mother to child, it is a maternal figure that determines intelligence. [7]

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Controversies

• Theoretically, mothers are likely to pass intelligence genes to their children as they contribute two X chromosomes. However, this could not be true in all the cases as the key gene for intelligence is not yet proved to be located exactly in the X chromosome.
• This says that intelligence is not dependent on just a single gene but hundreds and thousands of genes that affect together and signify intelligence.
• Environmental factors such as socioeconomic and financial factors play a great role in defining intelligence.

To Conclude

It is difficult to point out the exact origin of intelligence. This is because, one parent, in many cases, has a greater influence that determines the child's thinking and cognitive abilities, along with other factors like emotional attachment, nutrition and environment.