IQ-Brain Blog

IQ and age (part II)

IQ and age
IQ and age effects are clear

In my last posting here, I provided a brief overview about IQ and age. The brain develops quickly in childhood and in early adolescence. It has been argued that the brain reaches its full cognitive ability potential by the age of 16. This is illustrated by the fact that high IQ societies such as Mensa measure all test takers who are 16 years and above on the same adult IQ scale.

I also wrote about how Binet’s old IQ quotient calculation method i.e. IQ = (MA/CA) x 100, where MA is the “Mental Age” of the test taker, while CA refers to the test taker’s “Calendar Age” is a useful tool for understanding the generation relationship between IQ and age. More specifically, children who are ‘fast’ or ‘bright’ for their age will have an MA > CA, which means that these children will be classed as having an IQ score of more than 100.  I also wrote about the break down of the Binet IQ quotient method as test takers enter into their late teens and 20s, and this problem is exacerbated for older test takers.

For this reason, all noteworthy IQ tests have gotten rid of the quotient calculation method, and instead replaced it with standard scores, where a mean and standard deviation is established for each test.

With the statistical upgrade to IQ testing, what have we learned about the interrelationship between IQ and age?

IQ and age: fluid intelligence data is clear

Firstly, fluid intelligence (Gf) – or our ability to solve novel problems, peaks in our mid 20s and begins to decline thereafter, This very finding actually calls into question the fairness of high IQ societies measuring the IQ of test takers of 16 and above on the same ‘adult’ scale. Based on this finding, and all else being equal, one would expect the average 25 year old to perform better than the average 16 year old.

The bad news however, is that fluid IQ declines thereafter and fairly rapidly in our late 40s. Again, the relationship between IQ and age is rainbow-shaped. That is, IQ will increase between the ages of 1-25, peaks and plateaus in our late 20s, and begins a gradual decline in our 30s, before falling more precipitously thereafter.

So coming back to these high IQ societies, it becomes clear again that the average 25 year old will be expected to have a higher fluid IQ than the average 50 year old.

In my next post, I will explain how this finding affects IQ testing methods and what it means for test takers.

In the meantime, you can test your fluid IQ here.

IQ and age (part I)

IQ and age relationship
IQ and age are related. Binet’s methods would highlight the problem

The relationship between IQ and age is a complex one. At its roots, IQ testing as we know it today was developed by Frenchman Alfred Binet in the late 1890s when he was asked by the Paris ministry of education to devise a test which would help weed out weaker children from the classroom so that ‘normal’ or ‘bright’ children wouldn’t be slowed down in their learning.

Binet would eventually come up with a concept of a quotient, which was represented as follows. The Intellectual Quotient (IQ) would be calculated as follows:

IQ = (MA / CA) x 100

where MA was the “Mental Age” of the test taker, while CA was the “Calendar Age” of the test taker. It can be clearly seen from the above equation that having an MA > CA would mean that the child’s IQ would have been greater than 100. If MA were  < CA on the other hand, that child’s IQ would have been less than 100. And if MA = CA, then that child’s IQ would have been exactly 100.

IQ and age – Binet’s equation highlights some of the issues

So at its very historical root, IQ testing is all about age. And how mental age (effectively how advanced your thinking is) inter-plays with your actual age. To illustrate the point very simply, if a 10-year old would be able to think logically in the same way that a smart 20 year old man is able to do, that 10 year old child would clearly be considered a genius and would have an IQ which is off the charts.

Conversely, if a 20 year old man has the cognitive ability of an average 10-year old, this man would be considered to be intellectually challenged and may be suffering from borderline mental retardation.

So the interplay between age and IQ was clear from the smart. IQ and age: it’s all about age and cognitive ability for your age. However, this very example demonstrated the problem with the quotient method.

If a 12 year old girl (CA = 12), has the cognitive ability for an average 20 year old, then her IQ would be calculated as follows:

(20/12) x 100 = 166

But what about a 40 year old  (CA = 40) with a cognitive ability to match the average 20 year old (MA = 20), does this person really have an IQ of (20/40) x 100 = 50?

Clearly this does not make any sense. What critics of Binet’s method was that it did not apply to adults because of this type of conceptual and mathematical incongruency. It would later become assumed that brains reach an ‘adult’ state around the ages of 15/16. Which means that the peak MA would need to be capped at 15/16. Indeed, Mensa for instance assume that you have reached an adult IQ state by the age of 17 as the bar is lower for both 15 and 16 year olds. So in other words, a 16 year old needs to get less right answers to reach an IQ of 132 (top 2% if test has standard deviation of 16 points) than a 17 or an 18 year old.

But again, this is inconsistent with findings that fluid intelligence (Gf) peaks in our mid 20s. before declining thereafter.

So in fact, MA should really have peaked at a level of MA = 25. This probably means that under the old Binet IQ calculation method, the test might have worked for say 3 to 25 year olds. The old IQ calculation method provides a good conceptual basis for understanding IQ and age relationships, even though the quotient method has since been replaced by standard scores. In my next posting, I will elaborate on IQ and age effects as we age.

To take an accurate online IQ test, click here.


Mozart Effect IQ

The “Mozart Effect” was first coined by Dr. Alfred Tomatis in his 1991 book “Pourquoi Mozart” (Why Mozart?). He used Mozart’s music to “retrain the ear” and argued that Mozart’s music had valuable therapeutic benefits. This aroused interest in the research community. A 1993 study by Rauscher et al. suggested that listening to Mozart led to an increase in test takers’ “spatio temporal” reasoning shortly after the listening session. In other words, listening to Mozart was believed to temporarily increased certain aspects of peoples’ cognitive abilities. The results of this study were misinterpreted by the press which would eventually end up publishing that the Mozard Effect led to a direct boost in IQ, even though the 1993 study had been clear about the temporary cognitive benefits of the music. This study would set the world on fire and would lead to a further 300+ research papers being published on the Mozart Effect IQ gains.

The topic became so well-publicized that the governor of the US State of Georgia attempted to set aside a budget of USD150,000 to ensure that every parent in the State was able to receive a Mozart CD for their children. The hopes placed on the Mozart Effect IQ gains were clearly very high even in political circles.

Mozart Effect IQ  gains – what is the verdict?

So what is the verdict on the Mozart Effect IQ gains? The literature is actually divided, but will an overall indicator of a null effect on permanent IQ gains. There are some studies which have concluded that gains might be seen on Spatial aspects of an IQ test, although further studies postulated that any such gains were probably associated with mood-boosting effects for those people who liked Mozart’s music.

The Mozart Effect and IQ
The Mozart Effect and IQ Gains examined

The Mozart Effect IQ gains have thus been widely investigated and Mozart has not proven to be the silver bullet in the realms of cognitive improvement.

So although Mozart himself was said to have an IQ in the 140s (Genius Level), listening to his music is unlikely to confer any significant IQ gains to his fans. The benefits are likely to be confined to listening enjoyment.

That said, I believe that IQ test preparation should incorporate Mozart’s music. Learning a new skills such as juggling increases the brain’s grey matter. Performing this reasonably complex skill while also being able to focus on a complex musical piece by Mozart will make you feel more alert on the day of the test, and this will ensure that your IQ test score is within the highest range that you may be able to achieve.

Listen to Mozart’s Sonatas 448 or 488 and take our IQ tests HERE.


IQ test preparation

IQ test preparation clock
Know your biological clock for best IQ test preparation

The fear of exams is well known. Many people, most notably women, report feelings of fear and anxiety before taking an exam. And levels of fear and anxiety may impact negatively on concentration level and test takers’ ability to deliver top marks for the exam in question.

But this fear can be exacerbated when taking an IQ test. IQ test preparation is different from other types of exams. The reason for this is quite simple: you don’t actually know what will pop up on the IQ test, and unlike studying for a geography or history exam for which you are made aware of the curriculum and given time to review study materials, IQ tests, particularly fluid IQ tests, will throw questions your way that you may never have seen before or which may be totally different from what you may have been expecting.

The question on a fluid IQ test may relate to (1) spotting a patterns; (2) rotating a figure in your mind; (3) spotting the odd one out;  and (4) completing a logical sequence, etc. etc. So any one of these types of questions can pop up in many different formats, which makes preparation for such tests nearly impossible.

So what it boils down to is feeling rested, sharp and focused on the day of the test. IQ test preparation involves feeling alert, and being ready to respond to anything that is thrown your way.

IQ test preparation tips:

1. One month before the test, learn how to juggle. This will activate the grey matter in your brain. Mastering how to juggle will also improve your hand eye coordination and may help you with processing speed (Gs), which is an important sub-component of fluid intelligence and certainly a critical success factor on the day of the test.  For maximum effect, have Mozart playing in the background.

2. Take a few online IQ tests to get a feel for the time pressures associated with the test. There are a few good free online tests, or most accurate ones such as our at

3. Get some exercise. 25-30 minute cardio sessions daily will improve your circulation and blood flow to your brain and maximize your chances of boosting your IQ.

4. Eat well. Start your day with berry-heavy protein shake. Concentrate your intake of carbs around lunch time, and eat light protein-heavy meals for dinner. Limit alcohol consumption to one glass of wine with your meal.

5. Sleep well. Feeling rested on the day of the test will help you obtain your best possible score. A lack of sleep is the best way to knock off up to 10 IQ points on the day of the test.

In summary, take care of yourself generally, but certainly in the run up to your IQ test for optimal IQ test preparation, and remember that taking a practice test online may help demystify  what might be thrown your way on the day. For those of you who want to take up to three accurate IQ tests online, click here.

Boost IQ

Boost IQ - can grey matter help?
Boost IQ – we know that grey matter may grow

The academic literature remains divided as to whether people can take active steps to boost IQ, certainly in adulthood.

Scientists tend to agree that over 60% of variations in IQ are explained by genetics. Although the 40% left to environmental factors appears to be a significant proportion at a first glance, studies have also shown that environmentally-related IQ advantages tend to dissipate in adulthood. In other words, the genetic explanation will end up prevailing over the longer term, and your IQ will end up being closely linked to IQs levels in your immediate family or very simply, will revert back to its pre-programmed level.

Boost IQ generally? or just IQ scores

So if IQ is largely genetically determined, what can you do, if anything, to boost IQ?

This question needs to be split into two prongs: (1) can you actually boost your intelligence?; and (2) can you boost your IQ score?

The second question is easy to answer in that people can definitely boost their IQ scores with practice. For this reason, Mensa will prevent test takers from sitting the test twice in a twelve month period. “Practice effects” as their are known, have been widely observed. That is, people can boost IQ scores by up to 8 IQ points by taking the same test twice, even though the answers of the first sitting may never have been revealed to the test taker. The reason for this is simple: a fluid intelligence test such as the one found at measures your ability to solve ‘novel problems’, or problems that you will never have encountered before. So if you see the same problem twice, your brain will be better prepared to solve the problem, and this problem is certainly no longer novel. So you can boost IQ scores at the very least.

Improving your true intelligence, on the other hand, is easier said than done. However, neuroplasticity does provide hope. It has been shown that learning new skills such as juggling, or learning a complex language, can help build your brain’s grey matter. Further studies on London Black Cab drivers have shown that these cab drivers’ brains experienced growth in the size of the posterior hippocampus. So whether brain training can actually lead to a general boost in IQ is another story.

I will provide you with my IQ-boosting brain regime in a future post. In the meantime, you can test your IQ here.

Average IQ at

Average IQ
The Average IQ is set at 100 rather than being calculated based on the Arithmetic mean

Many people have written in to ask whether their IQ falls within the average. Let me first start by laying the ground work before explaining what constitutes average IQ.

When ‘modern day’ IQ tests were first developed in the late 1890s by Frenchman Alfred Binet, he developed a simple equation for establishing someone’s IQ. The intelligence quotient (IQ) was presented as follows:

IQ = (MA / CA) x 100

Where MA was the Mental Age of the test taker. That is, MA corresponded to how well the test taker did relative to children of different ages, while CA was very simple the test taker’s Calendar Age, or age.

So if a seven year old  (CA = 7) , on a multitude of cognitive ability tests was performing at the level of the average five year old (MA = 5), then this seven year old would have an IQ as follows:

IQ = (5 / 7) x 100 = 71 points. In other words, this little boy was slow for his age.

If another seven year old boy performed at a level which was consistent with his seven year old peer group, on a cognitive assessment, then CA = MA = 7 and his IQ would be computed as follows under Binet:

IQ = (7/7) x 100 = 100. So this little boy would be average for his age with an IQ of 100.

If however, a little girl was also seven (CA = 7) but was able to perform at the level of the average eight-year-old (MA = 8), then this little girl’s IQ would be:

IQ = (8 / 7) = 114. So this little girl would be advanced for her age.

Based on this early quotient, for calculating IQ, the average  level of IQ would have corresponded to someone who had a cognitive ability that was consistent with his or her age group. So that person’s IQ would have been 100. If MA = CA, then IQ = 100.

In the 1930s, Weschler –  another IQ test inventor – would go on and replace the old quotient scale with standard scores. This was made possible because it was established that IQ scores  in general were normally distributed. And the beauty of the normal distribution is that it can be described using only two parameters: Mean and standard deviation.

With standard scores, the mean or average IQ score was maintained at 100, while the standard deviation could vary depending on the test. No matter what the standard deviation of the test is however, we know that roughly 68% of scores will lie within one standard deviation of the mean, while 98% of test results will fall two standard deviations from the mean score. These are very simply statistical properties of the normal distribution.

Today the most popular IQ tests will have a standard deviation of either 15, 16 or 24.

However. assuming a standard deviation of 15, psychologists have broadly agreed on the following with respect to IQ scores.

an IQ score below 70 is usually associated with cognitive impairment.

an IQ score between 71 – 80 is considered ‘borderline’ or well below average

a, IQ score between 81-90 is considered ‘low average’

an IQ score between 91 and 110 is considered ‘average’

an IQ score between 111 to 119 is considered ‘high average’

an IQ score between 120 and 129 is considered ‘superior’

and IQ score above 130 is considered ‘very superior’

So the question about average IQ depends on the context.

For instance, in terms of the population as a whole, an IQ score between 91 and 110 is considered by psychologists as being ‘average IQ’.

If I look at the same question in statistical terms, I could argue that 68% of the population is expected to have an IQ between 85 and 115, which means  that this could be argued to be ‘average IQ’.

But then again, the average IQ depends on one’s perspective. For instance, we know that medical doctors have an average IQ of 125. Which means that having an IQ of 100 would not be average among this group of professionals.

So average is a relative term. And the question becomes: “relative to what? or to whom?”

At, we have created a number of IQ tests which will position your IQ relative to the general population as a whole.

Click here to take our fluid intelligence test now.

IQ for Mensa

IQ for Mensa - brain test
IQ for Mensa – brain test

Mensa is a high IQ society who’s only qualifying requirement for membership is an IQ in the top 2% of the population on an approved test. There are a variety of well-known IQ tests which are administered by schools or by private psychologists alike. If you have taken one of these tests, you may be able to gain access to Mensa by submitting ‘prior evidence’ of having achieved a test score that was in the top 2% of the population at the time of the test. What is interesting about prior evidence is that people may be able to gain access to Mensa based on a score which they achieved a long time ago. Based on the fact that IQs vary over time and decline as we age, this suggests that it is possible for people to gain membership to Mensa even though they may not be able to achieve a score in the top 2% if they were to sit that same exam today.

So the way to view Mensa membership, is that people with a qualifying score that have, once upon in their lives, achieved a score in the top 2% of the population. On this basis, it probably fair to say that people who have recently been tested and are ‘fresh new members’ will probably have stronger cognitive ability than people who have maintained their Mensa society membership for a long period of time.

IQ for Mensa – what is the standard deviation

IQ for Mensa is a top 2% IQ score, once upon a time in your life time. IQ is assumed to be normally distributed and a normal distribution can be described by its mean and standard deviation. We also know that most IQ tests will have a mean of 100 and that 98% of test results  (if normally distributed) will be within two standard deviations of the mean. Most IQ tests will have a standard deviation of 15, 16 or 24 points. This means that IQ for Mensa is likely to be 130, 132 or 148 respectively.

So if you take a verbal Mensa test with a standard deviation of 24, and you score 148, your IQ is believed to be in the top 2% of the population, just as the person who score 132 on a Figure Reasoning Test (FRT) with a standard deviation of 16 points.

At, we aim to provide the most lifelike and accurate matrix reasoning test as is often administered by Mensa to assess fluid intelligence (Gf). Do you have an IQ for Mensa? Take out test here to find out.

IQ booster pills on the way?

IQ booster pills could be on the way
Could IQ booster pills be on the way?

Many researchers are now involved in the evaluation of ways to halt the effects of ageing. In terms of IQ and cognitive ability, I have written extensively on how General Intelligence (or G) can be decomposed into two broad types of intelligence: (1) fluid intelligence (Gf), which is akin to raw processing power of the brain and our ability to solve novel problems; and (2) crystallized intelligence (Gc), which is related to our ability to absorb and use verbal and general knowledge, and is more closely related to one’s formal education.

As one might expect, the effects of ageing on cognitive ability are not good. What we know from the academic literature on the subject is that fluid IQ tends to peak in our mid 20s and starts declining (and fairly steeply) thereafter. The news is a little bit more positive in respect of crystallized intelligence. That is, Gc peaks in our 50s, and begins a gradual decline thereafter. IQ booster pills or a pill that could end this decline would be the holy grail of cognitive ability preservation for a globally ageing population.

Surmising the situation, fluid intelligence (Gf) includes several sub-components of cognitive ability including: (i) processing speed (Gs); (ii) visualization (Gv) and (iii) short-term memory / working memory (Gsm).

One of the reasons why Fluid intelligence diminishes with age is that older people will see their processing speed, visualization and working memory deteriorate.

Crystallized intelligence, on the other hand, can peak much later if older people carry on reading and learning.

IQ booster pills on the way?

Researchers at the University of California, San Francisco and the Gladstone Institutes had been investigating ways to stifle the effects and the role of ageing of klotho, a protein which is encoded by the gene known as KL. It had been discovered that a particular version of the gene, called KL-VS (believed to be present in 20% of human beings), promotes longevity. KL-VS had been shown to increase longevity by decreasing age-related heart disease. But when the researchers turned their attention to the effects of KL-VS on cognitive ability or IQ, they found that KL-VS did not curb the decline (gravity is inevitable), as they had hoped, but instead they found that KL-VS did boost IQ by up to 6 points, regardless of age. If this result is confirmed by the research community, KL-VS will be the strongest IQ booster and explanatory factor of genetic IQ variation ever discovered. It is believed that KL-VS could explain as much as 3% of the total variation in human IQ. Although 3% may sound low, this number is multiples greater than other genes believed to explain cognitive ability which had been discovered previously. This finding is also significant as It could mean that an IQ boosting pill could be on the way.

The finding has now been confirmed in mice and other evaluations are ongoing. The applications are compelling: pharma companies might be able to make this into an IQ booster pill format which could help boost the IQ of people who do not have the KL-VS variant of the gene. This would be the IQ booster breakthrough of the Century, and the enable some of us to sharpen our senses.

To test your fluid intelligence, click here.

IQ scales explained – part V

IQ scale - the importance of norming
IQ scale – standard scores would revolutionize IQ testing although of the scale remains key

This is part 5 of a series of posts in which I explain the coming of the modern-day IQ scale. The introduction of standard scores by Weschler in 1939 would change the art of IQ testing for the better in that IQ score volatility was greatly reduced, and IQ scores would therefore become more meaningful and reliable, even as the test taker aged. Despite what seemed like a no-brainer upgrade to IQ testing, it would then take a further 25 years before the publishers of the different versions of the Binet test got rid of the antiquated (MA/CA) x 100 IQ scoring method, and propel the IQ scale into with 20th century with the introduction of standard scores.

Most contemporary IQ scales are based on standard scores, which confers a neat advantage to the test assessor who is able to assess the intelligence of each test taker and to evaluate how an IQ test score compares to the general population.

Most known IQ tests are set to have a mean score of 100, and a standard deviation of either 15, 16 or 24 points. A Z-table can then be used by the assessor to establish the percentile score of the test taker in question. The percentile score gives the test taker a relative positioning of his or her own intelligence in relation to the general population.

However, as I discussed in my first posting on the topic of IQ scales, these need to be carefully crafted by way of a robust norming exercise to ensure that results and interpretations associated with the test statistics can truly be extrapolated to the general population as a whole.

Thinking back to Binet, who in the early 1900s developed an IQ test to help the Paris ministry of education to weed out intellectually weaker children from the classroom, Binet would need to recruit a large number of children to hone his Mental Age (MA) scale. Once his MA scale had been created, it was unclear as to whether this scale would have been applicable and representative of children living outside Paris, or how balanced the sample of children was across economic or social classes. The most likely scenario was that Binet had developed a Parisian IQ test for children, rather than a French IQ test.

IQ scales – the importance of robust norming

For this reason, Weschler would decades later spend a very large amount of time and money with his psychologist friends to recruit as representative a sample as possible of US test takers. Weschler had set his sights on understanding the intellectually ability of the entire United States of America.

The picture that emerges here is that IQ scales must be carefully normed relative to the country where the testing is taking place. Now, the Flynn effect tells us that the populations of several industrial nations have experienced an average increase in IQ by between 2-7 points per decade. The United States, for instance, has experienced a Flynn effect of 2-3 points for decade since the turn of the 20th Century, while the Netherlands have experienced a 6-7 point Flynn effect, largely over the same period.

This has several implications for IQ testing and I will discuss these in future postings.

You can test your IQ here.

IQ scales – how do they work? (part IV)

IQ Scales modernized by Weschler
IQ scales were modernized by Weschler

This is part IV in a series of posting about IQ scales.

In my last posting here, I explained how Binet’s IQ scale and equation of IQ = (MA/CA) x 100 would eventually come to be replaced by standard scores, introduced by Lewis Terman in the 1920s.

The beauty of standard scores is that they represented a great way of establishing the distribution of scores of test takers with only two variables: mean (or average) and standard deviation (SD). The introduction of standard scores eliminated the bizarre volatility that was associated with the Binet scale as test takers aged beyond adolescence.

But despite this clear advance in statistics, test publishers including Binet were averse to change. It was Weschler who in 1939 decided to change the IQ scale on his test and to adopt the upgrade of standard scoring methodology. Not only did the Binet tests keep the old quotients, but it was not until the 1960s that Binet would end up caving and adopting the much more reliable standard scores.

IQ scales – statistical properties introduced

The properties of a standard deviation are very neat:

  • We know that roughly 68% of all observations fall within 1 SD of the mean. In plain English, this means that 68% of the population will have a score of 100 + or 1 the SD of the mean (assumed to be equal to 100). So if the test in question has an SD of 15, this means that 68% of the population will have a score between 85 and 115
  • About 95% of the population will have a IQ score which is two standard deviations away from the mean of 100. And so 95% of test scores fall between 70 and 130
  • About 99.7% of the population will have an IQ score which is three standard deviations from the mean, translating into an IQ range of 55 to 145

No matter what the mean and the standard deviation change to, the IQ scale distribution should be the same, provided of course that the results on the test are normally distributed across the entire population.

So IQ scales are relatively simple, although the norming part of the test is significantly more challenging.

At, we compute distribution statistics which will let you know how your score stacks up relative to the population as a whole. A IQ score of 132 or more places you in the top 2% of the population.

Try out tests here.