A new study in which scientists from five different countries have collaborated, Spain, the United Kingdom, the United States, Canada and France, affirms that the rate of change in the thickness of the cerebral cortex is a determining factor in the intelligence quotient (IQ) of a person and that this is not a fixed value throughout life. The work has been published in the journal NeuroImage .
The cerebral cortex is the uppermost layer of the brain (containing gray matter) and is normally a few millimeters thick; this has a key function in cognitive functions such as perception, language, imagination, thought, memory and consciousness.
How is it possible that measuring a person’s IQ in two different periods sometimes gives very different results? The usual explanation is that there has been a measurement error. The study has shown that dramatic changes in IQ reflect a true change in the individual’s cognitive ability.
To do this, the researchers conducted a study of 188 children and adolescents over a period of two years . The participants underwent MRI tests at six different locations in the United States. Assuming that the cerebral cortex begins to lose thickness after 5 or 6 years as part of its normal aging process, the analysis of the tests determined that:
– Participants with a significant increase in IQ did not have the expected thinning of the cerebral cortex
– Participants who presented the same IQ had a normal thinning of the cerebral cortex
– The participants who had a significant decrease in their IQ had suffered an exaggerated thinning of their cerebral cortex.
The study puts on the table that the changes in the IQ are real and are not based on measurement errors; IQ is not fixed, it can change, both for the better and for the worse, at different stages of life, and its relationship with the cerebral cortex is limited .
