Mind Matters Chapter 3: Intelligence

9 min read

This series of articles has been adapted from [Mind Matters in Children] by Dr Kenneth Lyen. It delves into both the normal as well as the abnormal functioning of a child’s mind, and gives practical advice on how to manage children’s mental health and problems like ADHD, dyslexia, autism and depression.


Does having high IQ mean we are highly intelligent? Some still do unexpectedly poorly in exams despite having high IQ, while those who with ‘lower IQ’ can still do very well. Let us try to understand what intelligence is, what the limitations of IQ tests are, and how our embracing of the tests affects our educational system.

What is intelligence?

Intelligence is a mental quality that includes:

  •  the ability to derive and store information, 
  • the capability of learning from experience, 
  • the skill of adapting to and manipulating the environment, 
  • the ability to understand and handle abstract concepts, solve problems, think critically and creatively.

How is intelligence measured?

In the early 1900’s, the French government asked Alfred Binet (1857-1911) to devise a test to identify children who were struggling at school so that they can be given extra help. Together with his colleague Theodore Simon, Binet developed the very first intelligence test, which was introduced in 1905 (3).

 In 1916, Lewis Terman, who was professor of psychology at Stanford University, revised Alfred Binet’s test and renamed it the Stanford-Binet intelligence quotient or IQ.

The first mass testing of IQ was done in 1917 with 1.7 million American soldiers fighting in the first world war. The soldiers were graded A to E, and those with grade A were trained to become officers. This was so successful that the armed forces decided to adopt the IQ test for officer training and selection. Lewis Terman then pressed for it to be used in schools, to improve their efficiency. In 1921, he initiated a long-term study on gifted children whose IQ was 135 or above, and were in the top 1% of his cohort (5).

Epidemiologists plotted the IQ scores on a graph and found that it adopted the shape of a bell; hence the term “bell curve”. Statisticians then arbitrarily took plus and minus 2 standard deviations from the mean (which is 100), noted that this corresponded to an IQ ranging from 70 to 130, and called this the “normal” range. Below 70, one is considered to have a low IQ, and above 130, a high IQ.

Can one Improve Intelligence Through Training? (20,21)

Until recently, the dogma was that IQ was static and unchangeable for most of one’s life and could not be enhanced through training. However, recent studies have shown that indeed IQ can be increased through repeated mental exercises. Several IQ tests involve vocabulary comprehension. By learning new and difficult words, their subtle nuances and the different categories they can be classified, one can score higher on IQ tests. Many parents and teachers give their children practice IQ tests, and indeed they have shown their kids to improve on IQ scores.

The Flynn Effect is the observation that over the course of the 20th century, IQ scores have risen by as much as 15 points. This is a significant and sustained increase involving both fluid and crystallized intelligence. The time-scale of the improvement is too short to attribute it to genetic causes. Proposed explanations of the Flynn Effect include better parenting, smaller family size, upgraded education, improved diet, and a healthier population. The effect seems to be tapering off in some developed countries, while IQ continues to rise in developing nations.

Is the Current Educational System Stratified According to Intelligence?

The current educational system, especially in Asia, is like a race. Students compete against each other through a series of tests with only the brightest emerging victorious at the finish line. There are limited pots of gold at the end of the rainbow, meaning that only the top performers will be allowed to win. Competition is driven by parents and by society. The rewards of getting into top schools, university, top professions, are enormous. Elements of the IQ test can be found in many school tests, such as entry into the Gifted Education Program, secondary schools, and universities.

Scholastic Aptitude Test (SAT) (22)

In 1926, several American universities decided to adopt the IQ test to standardise college admissions. The named their test the Scholastic Aptitude Test (SAT). Over the years, the SAT has evolved to be more than just an IQ test, and the name has also changed to Scholastic Assessment Test (SAT) to reflect that. Only candidates who score above a level set by each individual tertiary institution, will be admitted.

Modification or incorporating part of the IQ test has been used in many countries as part of the entry requirement to gain admission into educational establishment. Singapore, for example, has modified the IQ test and named it the Primary School Leaving Examination (PSLE) to determine which secondary education is appropriate for the 12-year-olds. There is also an IQ test conducted by the Singapore army for boys going into National Service in their late teens. Many countries include an IQ assessment as part of their test for admission to tertiary education. For example, the United Kingdom conducts a Universities and Colleges Admissions Services (UCAS), and international students applying for Australian universities must take the International Students Admissions Test (ISAT). Some medical schools in England require applicants to take the BioMedical Admissions Test (BMAT). The original Scholastic Aptitude Test (SAT) developed for entry into USA universities was adapted from an IQ test used in the American army. The test has since evolved over the decades, but some claim there are elements of the IQ test remaining inside.

How Good are IQ Tests? (18,19)

The concept of intelligence has evolved over the past century, and we have since expanded our definition of intelligence and have started viewing intelligence from different perspectives. However, the IQ tests themselves have remained relatively static. There are many tests available, including the Stanford-Binet we talked about earlier, as well as other popular tests such as the Wechsler scales. 

If it is the first time you are doing IQ tests, the unfamiliarity may set you back. But if you have been practising these tests, you will have an advantage over the first timers. Those unfamiliar with the language used to administer the test, will be at a disadvantage. In addition, coming from a different cultural or educational background, having an underlying condition like autism, ADHD, visual impairment, or feeling tired, ill, or depressed, can all have an impact on one’s score. 

IQ tests measure the speed at which you solve mathematical problems, analyse visual and language abilities, as well process memory and information. Hence the faster you solve problems, the higher your IQ. Criticisms of IQ tests include the fact that there are many other capabilities not measured by conventional tests, including emotional and social intelligence and creativity. 

Many special schools and classes for intellectually challenged children require an IQ test as part of the assessment. The gifted program also has an IQ test for admission. Keeping in mind the limitations of conventional IQ tests, why are we still placing so much emphasis on them?

What About Intellectual Disabilities? (25)

Ironically, to be accepted into special education (SPED) schools for the intellectually challenged, an IQ test is often conducted.

An IQ of below 70 is generally the cut-off point. One of the advantages of attending special education schools is the significantly smaller class sizes that can be a teacher-to-student ratio of between 1 in 3, to 1 in 12. This contrasts with mainstream school, where the teacher-to-student ratio ranges from 1 in 20 to 1 in 40. In addition, the teachers in SPED schools are specially trained to provide a more individualised approach to education. Music, art, sports, and socialising form a greater part of the curriculum.

With current trends towards inclusive education, it remains a challenge for the educational system of many countries to remove barriers for children with disabilities to attend the same school and class as their neurotypical peers.


Intelligence is a most interesting and controversial subject influencing how we regard others.  It is a good predictor of important life outcomes, including educational achievements, higher earning occupations, mental and physical health, and even one’s mortality. 

The IQ test has become embedded into our educational system, and acts as a gatekeeper for entry into education at many levels. The test has served its purpose well over the past several decades. However, with the ever-changing educational landscape and the rising importance of original thinking and creative ideas, we need to change our mindset. How can we free ourselves from IQ test’s iron grip?


1 Falck S. The psychology of intelligence. Routledge 2021. ISBN ISBN 9780367482930.

2 Deary IJ. Intelligence: a very short introduction. Oxford University Press 2020. ISBN  9780198796206

3 Wikipedia. Alfred Binet. 

4 Wikipedia. Lewis Terman. 

5 Wilson J. What your IQ score doesn’t tell you. CNN Health 2014.

6 Griffin T. How to improve your intelligence. WikiHow 2021.

7 Kuszewski A. You can increase your intelligence. Scientific American. https://blogs.scientificamerican.com/guest-blog/you-can-increase-your-intelligence-5-ways-to- maximize-your-cognitive-potential/

8 Ben. A brief history of the SAT and how it changes. Peterson’s 2017.

9 Panfiloff E. Are IQ tests accurate? Enhancing Brain.

10 Robson D. Can high intelligence be a burden rather than a boon?

11 Lyen KR. Intellectual disability.

Written by Dr. Kenneth Lyen
Illustrations by Sung Jernin


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