There have been a lot of articles circling the Internet, claiming that intelligence is passed down from mothers and not from fathers. These articles refer to ‘newest scientific research’ which proves that mothers are responsible for the intellectual capacity of their children, giving no credit to the genes of the fathers.
The story goes…
To give you a brief summary of the story (for those of you that haven’t read it), these articles claim that the research they are referring to has found that the genes connected to intelligence are found in the X chromosome, which the mothers always give in the primary stages of the formation of the embryo.
Namely, it is claimed that cognition is closely connected to certain genes found in the X chromosome and that these same genes are directly transferred to the child in the first moments of conception.
The articles refer to a study from 1996 (You can see the full study here) conducted on laboratory mice and they mainly take things out of context while referring to certain notes made in the study. However, if you only read the abstract of the study, you will understand that there is not a single sentence claiming that intelligence is inherited from the mother’s genes only.
Another study they are referring to, in order to reinforce the claims mentioned above, is ‘the latest study’ in Scotland, where scientists have found more information about the hereditary factor in the intelligence of every person.
The truth is, however, very different.
So let’s clear things out.
The studies are not ‘new’.
First of all, the studies the articles are referring to are not ‘new’ in any way. From what we could notice, these articles mainly refer to studies conducted in 1996 and 1984.
The latest study mentioned in some of the articles is published by ABC Science first in 2012 and then again in 2013, referring to recent studies which were conducted in Scotland on a group of nearly 2000 people aged 11, 65, 70 and 79.
Not even the newest studies refer to any kind of unique maternal contribution to intelligence.
In fact, the results from the research show that only 20% to 40% of our intelligence is inherited by our parents. It does not however mention any kind of contribution percentage from the mother or father specifically or separately. It further goes explaining that the environment plays the greatest role in the development of the individual’s intelligence and that the percentile contribution from the parents cannot be analyzed separately.
When it comes to the percentile contribution to intelligence from the parents, these genes are scattered all across and are not located in one single area or certain genes that are ‘responsible for cognition’.
Intelligence is far more complex than that.
The first and most important thing to note about intelligence is that there are different kinds of intelligence and they are all developed in different ways, all under the major effect of the environment and starting at an early age.
Education.com has a whole article on the effects of heredity and the environment on intelligence, where it summarizes a number of researches on intelligence and the factors that contribute to it. There you can clearly see that the factors range from nutrition, all the way to formal education, and you can also see the hereditary influence, where there is not a single line stating that mothers are solely responsible for the intelligence of the child.
Intelligence is far more complex than a simple statement claiming that it comes from a single place. It is true that almost half of it is genetically inherited by both parents (and these genes come scattered from different places), but the contribution from the parents can different in every person.
However, this hereditary percentage cannot exist without the constant effects environment has on intelligence. In fact, you cannot take out which 20%, 30% or 40% are exactly those which are inherited by the parents, as this is only a starting point for every mind which needs to grow to the 100% under the influence of the environment.
All in all, both parents are as important for the intelligence of the child during conception, as they are after birth and the greatest focus that parents should have is setting a proper environment for the growth of their child’s IQ.