What impact do you think the environment has on intelligence? For more than a decade now, the debate in the scientific community between supporters of genetic detrmenism (“genes are to blame”) and those who believe that the environment is a key factor in the development of the intellect. The truth is believed to be somewhere in the middle: according to a 2018 study, the environment can change the expression of key genes in the brain, affecting the intellect much more than previously thought. Scientists at the Charité Universitätsmedizin Berlin clinic analyzed the characteristics of a number of genes among 1,500 healthy adolescents and compared the results with intelligence and various neurological features.
The researchers focused on genes responsible for anticipating compensation in the part of the brain that makes decisions – the striped body. The results revealed a strong connection between epigenetic modifications of one particular gene and the general level of intelligence, suggesting that experience affects not only the work of the brain, but also how genes function at the basic level.
Gene expression is the process by which the inherited information from a gene is transformed into a functional product – RNA or protein.
What is epigenetics?
The field of epigenetics is the scientific study of inherited changes in gene expression (active and inactive genes) that are not associated with changes in the basic DNA sequence. Scientists have long known that when it comes to intelligence, we are not born with a rigidly defined set of mental abilities. Rather, these abilities are still dependent on environmental factors as children develop. If children live in resource-rich environments with loving parental care, they have a much better chance of becoming intelligent and well-rounded than if they grew up in terrible poverty faced with neglect or outright violence.
Research of this kind is necessary to help us understand how environmental factors can affect the mental abilities that teenagers acquire in childhood and adolescence. This is particularly true in the face of ongoing climate change, which can trigger a cascade of environmental disasters ranging from extreme weather conditions to crop failures and prolonged droughts in most of the world.
“Stress and adverse life experiences are examples of environmental factors that can affect gene activity, leading to structural changes in our genome,” the study’s authors write. These “epigenetic changes” allow the human genome to adapt to the environment, allowing our DNA to be transmitted to the next generation of cells, as well as information that determines whether a particular gene will be activated and under what conditions.
Epigenetics has become great news in genetics, as it allows scientists to explore the amazing connection between genetic functions and environmental changes.
“Previously, we could observe a connection between stress and cognitive indicators, especially with regard to the activity of the dopamine-controlled reward system in the brain,” explains Dr. Jakob Kaminski, lead author of the study from the Department of Psychiatry and Psychotherapy of the Charite Clinic. Environmental-induced gene activity is now joining a number of other factors that are known to influence IQ test results, such as poverty and genetic constitution.
Stress and the environment
For example, during severe stress, such as a constant threat of violence or poor nutrition, physiological changes in the body can change the work of the genes by adding or removing a chemical group that effectively turns them off or on. Stress in childhood is known to affect cognitive abilities as they grow older, although the extent to which it is associated with neurological changes and how epigenetic it can be is difficult to determine.
As Science Alert writes, with a great tension we can say that any single epigenetic change dooms us to a life of wealth, disease, or – in this case – intellectual superiority. Unlike other environmental influences, epigenetic changes hypothetically can be passed on to future generations.
Genes and the environment are the key to both intellect and general health.
In a paper published in the journal Translational Psychiatry, scientists were able to observe how individual differences in IQ test results are related both to epigenetic changes and to differences in brain activity under environmental influence. Intellect testing and debate have long gone hand in hand, often with good reasons. However, when we ask ourselves whether human intelligence is hereditary, formed upbringing, or the result of effort and diligence, we cannot give an exact answer today.
Obviously, this is a complex subject, but as the evidence accumulates, we will get a clearer picture of how our brain works to learn and solve problems.