In this YouTube video I discuss a paper that investigates if genes for normal intelligence are the same as those for people with “high intelligence.” 

Intelligence is a widely studied and debated subject. It is praised and admired…for the most part

We believe that intelligent individuals provide great technological and cultural advancements. We wish to understand why some of us seem to be smarter than others.

We largely believe that in a given population, people fall into a bell curve. Most people have an IQ around the average for that population, but there are also people at the extreme ends.

Those with substantially low IQs and those with exceedingly high IQs make up a small percentage of the overall population.

Many studies have shown evidence that IQ is highly heritable. Thus, consequently, much of IQ may be attributed to genetic factors.

A question that arises then, is are the genes that are responsible for “normal” intelligence the same as those for “high” or “low intelligence?”

Some studies have shown evidence that those with severe mental disabilities are likely to have rare genetic mutations that were not inherited from their parents.

But what about those with high intelligence? Can special genes explain their intelligence? What role does environment play?

Researchers at the King’s College of London wanted to get to the bottom…or top of this.

The researchers studied a group of 3 million 18-year-old males from Sweden who were required to take a cognitive test known as the Swedish Enlistment Battery (SEB) between 1968 to 2010!

Until 2009 all Swedish males were required to enlist in the Swedish military and thus, had to take this test.

The researchers took this group and identified twins and non-twin siblings with the top 5% highest scores. Then, using statistics, they investigated whether their high intelligence could be attributed to their genes or other factors.

The researchers found that the non-twin siblings of the “high intelligent” individuals typically did not score as high as these high performers, but still performed higher than the average Swede!

This is evidence that the genes that made the really smart people so smart were not necessarily unique to them and that brains run in the family.

But how do we know it was their DNA that made these siblings smart and not their similar upbringing?

Well, further supporting the gene hypothesis, is the evidence that an identical twin of a super smart person is more likely to also be super smart compared to a fraternal twin. (Though, again, the fraternal twins were still smarter than the average Joe.)

Overall, the results indicate that the high intelligence can be inherited just as normal intelligence and there is nothing unique about these genes that make up high intelligence.

Also, there is still an environmental effect on high intelligence!

So, although you can’t change your genes you can change your surroundings and perhaps you can study hard enough to increase your IQ.

Furthermore, if you want smart kids, find a smart mate.

This has been the Mindful Moment.

In Addition: The authors of the paper point out that more stringent criteria for identifying high intelligence such as the top 1%, 0.025%, or even 0.0001% may yield different results. It’s also important to discover the actual genes that contribute to intelligence. What is the interaction between positive genetics, genes that make a person smarter, and not having genes that are harmful to intelligence?

Reference

Shakeshaft, N. G., Trzaskowski, M., McMillan, A., Krapohl, E., Simpson, M. A., Reichenberg, A., & … Plomin, R. (2015). Thinking positively: The genetics of high intelligence. Intelligence, 48123-132. doi:10.1016/j.intell.2014.11.005

Thinking positively: The genetics of high intelligence, PMCID: PMC4286575, This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/3.0/)