Featured Research

from universities, journals, and other organizations

New evidence confirms link between IQ, brain cortex

Date:
March 4, 2014
Source:
McGill University
Summary:
Rate of change in the thickness of the brain's cortex is an important factor associated with a person's change in IQ, according to a collaborative study by scientists in five countries. The cortex is the thin, outermost layer of nerve cell tissue of the brain, typically measuring a few millimeters in thickness. The cortex contains nerve cell bodies and is critical for cognitive functions such as perception, language, memory and consciousness. The cortex begins to thin after the age of five or six as part of the normal aging process. This study is the first to show the association between cortical thickness and development in full scale IQ, and has potentially wide-ranging implications for the pedagogical world and for judicial cases in which the defendant's IQ score could play a role in determining the severity of the sentence.

The study has potentially wide-ranging implications for the pedagogical world and for judicial cases in which the defendant's IQ score could play a role in determining the severity of the sentence.
Credit: axentevlad / Fotolia

Rate of change in the thickness of the brain's cortex is an important factor associated with a person's change in IQ, according to a collaborative study by scientists in five countries including researchers at the Montreal Neurological Institute and Hospital -- The Neuro, at McGill University and the McGill University Health Centre. The study has potentially wide-ranging implications for the pedagogical world and for judicial cases in which the defendant's IQ score could play a role in determining the severity of the sentence.

Related Articles


The cortex is the thin, outermost layer of nerve cell tissue of the brain, typically measuring a few millimeters in thickness. The cortex contains nerve cell bodies and is critical for cognitive functions such as perception, language, memory and consciousness.

"Often, small differences in IQ scores are observed when people's IQs are tested twice over a period of time. However, in some instances, dramatic changes in IQ scores are observed," said Dr. Sherif Karama, assistant professor of psychiatry at McGill University, psychiatrist at Douglas Mental Health University Institute and affiliate at The Neuro where he conducted the study published in the scientific journal, Neuro Image. "These dramatic changes are generally attributed to measurement errors rather than assumed to reflect real changes in general cognitive ability."

The cortex begins to thin after the age of five or six as part of the normal aging process. This study by Professor Karama and his colleagues involved 188 children and adolescents over a period of two years. MRIs of the study participants were taken at six sites across the US. This study is the first to show the association between cortical thickness and development in full scale IQ. They found that within a relatively short period of 2 years:

  • people with a significant increase in IQ did not have the expected cortical thinning,
  • people whose IQ stayed the same had the normal expected cortical thinning,
  • people with a significant decrease in IQ had exaggerated cortical thinning.

"Finding that IQ is not fixed and correlates to changes in brain anatomy has important implications as it shows that some of the changes in IQ are real and not merely due to measurement error. This finding should make people wary of sticking to an early IQ assessment given the role it plays in school entrance criteria, detection of the gifted, as well as in eligibility for social security disability income or even the death penalty. In some US states, people with an IQ below 70 are not eligible for the death penalty."

The reasons behind the changes in IQ are not clear at this point. Some of these may be due to programmed developmental trajectories or other factors such as nutrition and education, noted Professor Karama.


Story Source:

The above story is based on materials provided by McGill University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Miguel Burgaleta, Wendy Johnson, Deborah P. Waber, Roberto Colom, Sherif Karama. Cognitive ability changes and dynamics of cortical thickness development in healthy children and adolescents. NeuroImage, 2014; 84: 810 DOI: 10.1016/j.neuroimage.2013.09.038

Cite This Page:

McGill University. "New evidence confirms link between IQ, brain cortex." ScienceDaily. ScienceDaily, 4 March 2014. <www.sciencedaily.com/releases/2014/03/140304141734.htm>.
McGill University. (2014, March 4). New evidence confirms link between IQ, brain cortex. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2014/03/140304141734.htm
McGill University. "New evidence confirms link between IQ, brain cortex." ScienceDaily. www.sciencedaily.com/releases/2014/03/140304141734.htm (accessed October 23, 2014).

Share This



More Health & Medicine News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Fears Keep Guinea Hospitals Empty

Ebola Fears Keep Guinea Hospitals Empty

AP (Oct. 23, 2014) Fears of Ebola are keeping doctors and patients alike away from hospitals in the West African nation of Guinea. (Oct. 23) Video provided by AP
Powered by NewsLook.com
Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Orthodontist Mom Jennifer Salzer on the Best Time for Braces

Working Mother (Oct. 22, 2014) Is your child ready? Video provided by Working Mother
Powered by NewsLook.com
U.S. Issues Ebola Travel Restrictions, Are Visa Bans Next?

U.S. Issues Ebola Travel Restrictions, Are Visa Bans Next?

Newsy (Oct. 22, 2014) Now that the U.S. is restricting travel from West Africa, some are dropping questions about a travel ban and instead asking about visa bans. Video provided by Newsy
Powered by NewsLook.com
More People Diagnosed With TB In 2013, But There's Good News

More People Diagnosed With TB In 2013, But There's Good News

Newsy (Oct. 22, 2014) The World Health Organizations says TB numbers rose in 2013, but it's partly due to better detection and more survivors. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins