The Influence of Genetics And Environment on IQ Test Results

What Affects The Level of Intelligence?

Like the majority of behavioral and cognitive qualities of humans, intelligence is a complex attribute impacted by a combination of hereditary and environmental influences.

Because intelligence can be defined and measured in a variety of ways, it is a challenging concept to investigate. The capacity to draw lessons from experience and adjust to a changing environment is a feature shared by most definitions of intelligence. The capacity for abstract thought, problem-solving, reasoning, planning, and understanding complicated concepts are among the components of intelligence. The intelligence quotient (IQ), a measure of intellect, serves as the foundation for numerous investigations.

IQ tests or tests to determine the level of intelligence is a common name for tests created over the years to measure intelligence in different groups of people. There is no single standard and universal IQ test. However, we recommend the IQ test from CerebrumIQ. You will better understand the advantages of the platform thanks to CerebrumIQ reviews.

Studies on The Relation of Genetics to IQ Levels

Thus, since research on this topic started in the late nineteenth century, there has been a great deal of discussion over the inheritance of IQ in the academic world. Many investigations have been carried out in an effort to identify the genes that influence intelligence. Numerous studies highlight the IQ parallels and variances within families, with an emphasis on twins and foster children in particular. These findings indicate that around half of the variances in IQ between people can be attributed to hereditary causes.

To find out if any particular genomic areas are linked to IQ, other researchers have analyzed variations throughout the genomes of numerous individuals using a method known as genome-wide association studies. These investigations haven't conclusively found any genes that are crucial to the variations in IQ. It is possible that many genes are involved, although the contribution of each gene to human intellect is probably quite tiny. For instance, the genes underlying human language skills have been identified. Interestingly, human spatial abilities (e.g., orientation in place) are likewise linked to the same genes.

The IQ levels of the children and teenagers in the sample were assessed while the scientists watched them grow. The data collected showed correlations with the IQ levels of biological parents and foster families, as well as with the standard of living, money, and a few other factors that characterized the families in which the children resided. The dynamics of changes in intelligence during observation and the impact of the environment on such changes were also examined by experts.

Is Intelligence Inherited or Acquired?

The main points of contention between the scholars are the proportions of innate vs acquired intelligence and the influence of the environment on intelligence development.

Proponents of the inherited theory of intelligence estimate that hereditary variables account for 85% of an individual's IQ, with the remaining 15% attributed to environmental circumstances. Among those who hold these opinions is Arthur Jensen, a social psychologist. The scientist based his conclusions on research with related children who were raised in dissimilar social environments. The scientist compiled the information from over 200 different scientific studies in total. The psychologist concluded that the only things that may affect these kids' IQs were external ones.

Jensen noticed that in identical twins, when raised together, genetic factors caused a correlation coefficient in the level of intelligence equal to 0.83 (where 1 would correspond to the limit value of correlation). Identical twins who were raised separately had a correlation in the level of intelligence of 0.74. The correlation in the level of intelligence in fraternal twins when living together was 0.59.

Meanwhile, this indicator between the level of intelligence in foster children raised together was only 0.26. Apparently, the results of Jenson's generalization may indicate that a significant part of the level of intelligence is due to the influence of genetic factors.

Does the Environment Affect Intelligence?

A study conducted in 2018 by scientists from the Berlin Charite Clinic showed that the environment can alter the expression of key genes in the brain, affecting intelligence more strongly than previously thought. The researchers focused on the genes responsible for reward expectation in the striatum and found a close relationship between epigenetic modifications of one particular gene and the overall level of intelligence. This suggests that experience affects not only brain function, but also how genes function at a basic level.

What is Epigenetics?

Epigenetics is the scientific study of hereditary changes in gene expression that are unrelated to changes in the basic DNA sequence. The study highlights the importance of understanding how environmental factors can affect the mental abilities acquired by adolescents in childhood and adolescence, especially in the context of ongoing climate change.

Environmental-induced gene activity is now combined with other factors that are known to affect IQ test scores, such as poverty and genetic constitution. It is unclear whether any particular epigenetic change condemns us to a life of prosperity, illness, or intellectual superiority. As evidence accumulates, we will gain a clearer understanding of how our brains work to learn and solve problems.

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