IQ boosting foods

Gotu Kola: is it really on the list of IQ boosting foods for healthy adults?
IQ boosting foods may include Gotu Kola supplements for children with mental retardation

Diet most definitely plays a part in improving or maintaining your IQ. There are plenty of foods which are reported to enhance mental alertness and even possibly enhance IQ. So you not only need to consider your waist line when it comes to diet, but you also need to consider the impact of what you eat on your brain and your mental processing abilities.

Let’s look at a list of possible IQ boosting foods. We will attempt to categorize them into moderately high evidence, medium evidence and low evidence of possible effects on the brain.

Moderately high evidence

  1. Creatine: often used by bodybuilders, creatine is a nitrogenous organic acid that occurs naturally in vertebrates and helps supply energy to all cells in the human body. An Australian study found that creatine supplementation in the short term provided a significant boost in brain power including memory. Refinements on this study found that creatine supplementation was able to negative the negative effects of sleep deprivation.
  2. Omega and fish oils: supplementation by either pregnant mothers or to young infants has been shown to increase IQs of children by up to 3.5 points. A study in northern England also found that pupil performance improved with fish oil supplementation. Some studies have also found that consumption of fish oils conferred an IQ advantage in adults. Although omega and fish oils are IQ boosting foods, the purity of the oils is also a critical component.

Medium-evidence IQ boosting foods

  1. Gotu Kola: is a pervasive south Asian herb. Its supplementation has been shown to improve IQs of children with mental retardation by up to 10%. It is not clear whether this herb can achieve the same feet in normal children or adults.
  2. Blueberries: some studies have found that their consumption may improve memory in older adults with age-related memory problems. Berries contain flavonoids have recently been found to confer positive benefits to the brain. Whether or not blueberries are really an IQ boosting food remains unknown, but these tasty foods certainly fall in the category of super foods and are thus worth adding to one’s diet.

Low-evidence IQ boosting foods

  1. Gingko Biloba: is a herb that has long been claimed to boost memory and concentration. Although the strongest early evidence in its favor related to the treatment of Alzheimer’s, recent meta analyses have suggested that the herb does not alter the progression of the diseases and that memory or problem-solving abilities are not enhanced by its consumption. This one should really fall off the list of IQ boosting foods.

You may want to test your baseline IQ here, and to re-test once you have added these elements to your diet.

Famous people with high IQ

Da Vinci is one of the most extraordinary famous people with a high IQ
Leonardo da Vinci had an IQ in excess of 160

The list of famous people with high IQ scores is a long one. Before listing some key individuals, let’s first revisit what is means to have a high IQ. In any nation, the average IQ is set to 100 and a normal distribution is able to be set around this mean. Around 95% of the population will have an IQ score between 70 and 130, which implies that roughly 2.5% of the population will score <70 while 2.5% of the population will score above 130. IQ scales are classified as follows:

IQ range (16 SD)

Classification

Population distribution

130+

Very Superior

3%

120-129

Superior

7.5%

110-119

High Average

16%

90-109

Average

47%

80-89

Low Average

16%

70-79

Well below average

7.5%

69 and below

Lower Extreme

3%

 

As can be seen from the above table, IQs between 110-119 are still considered to be high average. So one can take the view that an IQ in excess of 120 is a high IQ. An IQ of 120 places you in the top 10.5% of the population (or 1 in 9 people). 5% of the population have an IQ in excess of 125 (1 in 20 people), while only 3% of the population have an IQ in excess of 130 (1 in 33). 1% of the population score in excess of 135, while 1 in 192 people (0.43% of the population) score in excess of 140. Incidentally, an IQ of 140 of more is considered genius or near genius level.

There are plenty of celebrities and famous people with high IQs in excess of 140.

  • Leonardo da Vinci: was estimated to have an IQ of 180, which decreases to 158 adjusting for the Flynn effect. This represents a rarity of 1 in 6,900. In terms of famous people with high IQs, he is perhaps one of the greatest visionaries and most multi-talented. Not only was he a fantastic artist, he also contributed to the world of science with designs of the human body, flying machines, scuba gear and the parachute, and all of this in the mid the late 1470s
  • Wolfgang Amadeus Mozart: was estimated to have an IQ of 165, although adjusting for the Flynn effect, his IQ would most likely be 143 in modern terms. Irrespective of the adjustment, an IQ at this level is seen in less than 1 in 278 people. No wonder why Mozart was writing symphonies from the age of 8 and that his music is still being played in households around the world nearly 225 years after his death. It remains to be seen whether even the Beatles are able to achieve such a feat.
  • Albert Einstein: is reported to have an IQ of 160 (1 in 11,000 people). With his theory of relativity E=MC squared, he has changed the world of astrophysics.
  • Bill Gates: has an IQ of 160. It comes as no surprise that he was able to develop a program that would become ubiquitous in the world of computing and modern communication. Bill Gates deserves not only to be included in the list of famous people with high IQs, but also great inventors

There are plenty more famous people with a high IQ. We will revisit this topic in future posts.

To test your own IQ, click here.

Highest IQ in the world

Terrence Tao is meant to have the highest IQ in the world
Terrence Tao is said to have the highest IQ in the world

Unlike other human characteristics, IQ is not as straightforward to accurately measure. Weight, height and even human strength can be measured with a much greater degree of accuracy. Alfred Binet, one of the forefathers of IQ testing, made one of the biggest contributions to the science by simply pointing out that human intelligence and IQ could only be estimated with a degree of error. So it therefore follows that handing out the designation of “highest IQ in the world” is subject to some degree of error and speculation.

With that in mind, there are quite a few web resources that hand out titles for highest IQ in the world. Let’s investigate a few of them.

  • Terrence Tao: is reported to have an IQ between 220 and 230 (most likely this is closer to 200). Based on a SD of 16, this implies a rarity of 1/11 Billion. This result appears contradictory given that the world population of 7.1 billion. What this illustrates is that ‘black swan’ outliers that are ‘off the charts’ exist when it comes to the highest IQ in the world. So what makes Terrence so smart? First off, he was solving arithmetic problems by the age of 2 when most of us were content with relieving ourselves in our diapers. He went on to score a 760 in SAT math by the age of 8. He also was the youngest ever participant in the mathematics Olympiads, winning bronze, silver and gold in 1986, 1987 and 1988 respectively (he was only 13 when the latter happened!). He graduates with bachelors and masters degrees by the age of 16, winning a Fullbright scholarship to attend Princeton University where he gained his PhD by the tender age of 20. He was appointed a full time professor at UCLA by 24
  • Christopher Hirata: has an IQ estimated around the 195 mark. Christopher was adding up the cost of his parent’s grocery shopping chart by age 3. By age 12, he was taking college level course in physics and calculus. By 13, he won the gold medal at the international physics Olympiad becoming the youngest ever participant to win that distinction. Hirata completed his BSc in mathematics at Caltech by the age of 18 with a GPA of 4.2 and his PhD in physics from Princeton by age 22. He is currently a visiting professor in physics and astronomy at Ohio State University.

Highest IQ in the world: characteristics

So the two case studies for highest IQ in the world share a lot in common: (1) IQ around 200, which represents a rarity of 1/11 billion; (2) a very early display in mathematical abilities; and (3) unique academic achievement from a very young age. Even if the measurement of IQ is not perfect, these two individual’s unprecedented achievements signal unparalleled raw talent.

But you don’t have to look very far to find smart people. We have already found several people with an IQ of c.140 on IQ-brain.com. To find out how you measure up, click here.

High IQ

120 is a high IQ
High IQs can be found to the right of the normal distribution

What does it mean to have a high IQ? Well the first question to ask is “high IQ relative to whom?” Let us provide some background: relatives of modern-day IQ tests have been around since the late 1890s. The millions of test observations have enabled mathematicians and statisticians to establish several important characteristics about IQ scores. Namely, across a population, IQs follow a normal distribution which means that the same proportion of people will score higher than the average IQ score (usually set to 100), as the proportion of people scoring below the average score. In other words, 50% of the population have an IQ which is greater than 100, while the other 50% have an IQ lower than 100.

To be able to get a complete picture of the statistical properties of IQ however, you also need to know the standard deviation of the test that is being employed to measure the IQ score. The standard deviation measures the dispersion around the mean of all the test observations (scores) in your sample, or for the population. Most IQ tests have a standard deviation of either 15 or 16 (some tests such as Cattell have a standard deviation of 24).

A high IQ can be established by looking at statistical properties of the normal distribution

The beauty of the normal distribution is that once you know the mean (average) and the standard deviation, you can then calculate the percentile (and rarity) of a particular test observation or IQ score. Statistics tell us that about 68% of the population will have an IQ score which is 1 standard deviation (SD) away from the mean. So if the SD of a particular test is 15 for instance, we know that 68% of the population have an IQ between 85 and 115 (i.e. the mean of 100 + or – 15 SD points). About 95% of the population will have an IQ falling within 2 standard deviations of the mean. This means that 95% of people will score between 70 and 130 (again SD 15).

So from a statistical standpoint, you are comparing yourself to the average person (which is assumed to have an IQ score of 100) when you are interpreting your score. So let’s revisit the initial question of what a high IQ represents.

Given that the average score is 100, a high IQ will necessary start to the right of the distribution which is centred on the mean of 100. Most psychologists will agree that an IQ score between 90 and 109 falls withing the average category. A score of 110 to 119 is considered high average. 120-129 is superior intelligence, whilst IQs greater than 130 are considered very superior, a category which is something flatteringly referred to as ‘near genius’.

So we have seen that IQs between 110 and 119 are still considered to be high average. It is therefore not unreasonable to argue that a high IQ starts around 120.

The easiest ‘high IQ society’ to qualify for is Tensa, which requires a score in the top 10% or about 120. The International High IQ Society accepts a score in the top 5% (124 IQ with SD=15), while Mensa accepts applicants with an IQ score in the top 2% of the population (130 IQ if SD=15). Several other  societies including the 999 society are much more selective, requiring a score in the top 99.9% to enter.

High IQ societies abound. But on a practical note, It is said that you can do virtually any job if you have an IQ of at least 115. So from a practical standpoint, a high IQ can be said to start at 115.

Find out about your IQ by taking our culture-fair IQ test here.

Mensa IQ test

Mensa IQ score in the top 2% is required to qualify for membership.
Mensa requires an IQ in the top 2%. Other high IQ societies may require higher or lower scores.

What is Mensa? And what is the Mensa IQ test? Mensa is a high IQ society which traces its roots back to 1946. The society was founded by Englishmen Roland Berrill, a barrister and Dr Lance Ware, a scientist and lawyer.  The founders sought to create a society where the only qualification for admission was a high IQ, which would be ascertained via a Mensa IQ test or a recognized professionally-administered test. Mensa is a non-political organisation that is free from all social distinctions.

The society’s official objectives are as follows:

  • to provide a stimulating intellectual and social environment for its members
  • to identify and foster human intelligence for the benefit of humanity
  • to encourage research into the nature, characteristics, and uses of intelligence

Mensa IQ test qualifying scores

Mensa membership is available to individuals who have an IQ score within the top 2% of the population (i.e. a score in the 98% percentile). One in 50 people have the intellectual ability to qualify for Mensa. Aspiring members can either submit prior evidence of having achieved a score in the top 2% on an acceptable IQ test (e.g. Standord Binet, Weschler, Cattell) or can sit a Mensa IQ test (Mensa administers its own admission tests in some countries), but many also sit well-established IQ tests that are administered by Mensa volunteers in a group-test setting. Mensa has local societies in several countries, and the Mensa IQ tests administered may vary from country to country.

Why is the Mensa IQ test threshold set at 2%? The 2% is arbitrary. There are several high IQ societies which may have stricter or looser standards for admission. For instance, the International High IQ Society admits for membership individuals with an IQ in the top 5% of the population (i.e. 1 in 20 people would qualify), while the 999 society admits individuals with an IQ score in the 99.9% (i.e. 1 in 1,000 people could qualify).

The average IQ score of the general population is assumed to be 100. Because IQ follows a normal distribution, this means that 50% of the population will have a score that is greater than 100, and 50% of the population will have a score that is lower than 100.

The Mensa IQ test score for entry depends on the test taken. For instance, the Cattell verbal IQ test has a standard deviation of 24, which means that an IQ score of 148 (i.e. a score that is two standard deviations above the mean of 100 places you in the top 2% of the population) is required to qualify for Mensa membership. Stanford-Binet, on the other hand, has a standard deviation of 16, which means that a score of 132 would be required to qualify for membership. So the IQ test score doesn’t mean anything without also knowing the standard deviation of the test taken.

Mensa IQ tests (or tests administered by Mensa) place great emphasis on speed. The group-tests will usually comprise a test which measures crystallized intelligence (i.e. mainly verbal) and another which measures fluid intelligence (i.e. culture-fair IQ testing). The one common characteristic of these tests is that speed is of the essence.

Have you ever wondered what your fluid intelligence is? If so, you can try our robust test here.

Alternatively, if you think you might want to sit a Mensa IQ test, we strongly recommend that you practice here. Practice will help eliminate some of the level of surprise associated with the test, and will ensure that you perform at your best on the day of the test. Click here for Mensa IQ test practice questions.

IQ and success

The link between IQ and success is clear. Professionals win.
The link between IQ and success is clear.

How do you define success? The Oxford English Dictionary defines success as “the accomplishment on an aim or purpose”. Although I adhere to capitalistic principles, I also recognize that monetary success may not be what everyone aspires to. Artists such as Rodriguez (Searching for Sugarman) was clearly not interested in financial pursuits or a life of luxury. His success and happiness lied in performing and making audiences happy with his music. Shifting gears, Grigori Perelman, a Russian mathematician of Jewish descent solved amongst others, the Poincaré conjecture, which was renowned as being the most difficult problem in mathematical topology. Perelman probably has an IQ well in excess of 170, which would evidently place him in the category of “extraordinary genius”. Despite his high IQ and mathematical discoveries, Perelman turned down the Fields Medal in mathematics as well as the Millennium Prize, where he declined an award of USD 1 million.

For the vast majority of us however, it is probably fair to say that most people will define success in financial and professional terms. Establishing a link between IQ and success is probably best done by looking at IQ scores for different categories of workers.

But you don’t need a scientific study to see the link between IQ and success. It would be difficult to argue that a security guard is more successful than a medical doctor for instance. And clearly, becoming a medical doctor is much more difficult than becoming a security guard.  In other words, becoming a doctor requires a higher IQ and certainly much more effort.

Turning to the academic literature for confirmation, the link between IQ and success is clear. Adult professionals in the United States earn Weschler scale IQ scores that are on average 25 points higher than those earned by unskilled laborers. Interestingly, the children of professionals also have average IQs that are 21 points higher than those of unskilled laborers. So not only is there a link between IQ and success, but this type of link appears to be hereditary, or at least perpetuated by the environment created by individuals with more highly skilled professionals and therefore living standards.

IQ and success 

Labour group

Adults

Children

 

Professionals and technical

112

108

Managers / administration

104

103

Clerical, crafts

101

100

Semi-skilled workers

92

96

Unskilled workers

87

87

*source: IQ testing 101 by Alan S. Kaufmann

As discussed previously, one way to improve your IQ is to remain in school for longer and to pursue higher education. Undertaking more education will not only assist in increasing your crystallized IQ, but makes it possible to access a better career. This in turn allows the individuals concerned to create a better quality of life for themselves and their children.

Higher fluid intelligence is known to assist in one’s investment in their crystallized intelligence. Discover your potential by taking our Fluid Intelligence Test here.

Improve your IQ

Being a lifelong student can help improve your IQ
Remaining a student for longer can help improve your IQ and intelligence

As discussed in previous posts, IQs can change over time. In particular, IQ scores may change fairly substantially during childhood and typically stabilize in your teenage years. This can be seen as good news as there may be scope to influence the development of IQ . But it is important to distinguish between the different types of intelligence and how easy it is to improve each type. We also emphasize in this post that it it much easier to improve your IQ score than it is to genuinely improve your intelligence, although both are possible with practice, dedication and suitable lifestyle choices.

In simple terms, general intelligence can be decomposed into two parts: (1) Fluid intelligence, which represents one’s ability to solve novel problems; and (2) Crystallized intelligence,  which relates to one’s ability to learn, retrieve and apply concepts that are either taught or learned. Crystallized intelligence for instance, is much higher in people who pursue advanced degrees or who read a lot of intellectually stimulating materials.

Now that we understand the broad types of intelligence, how do these change as we age?Fluid intelligence peaks in our mid 20s, and begins a fairly steep decline thereafter. Crystallized intelligence, on the other hand, grows steadily until your mid 50s and begins a gentle decline thereafter. Scientific studies therefore confirm that IQ levels change naturally over time, although is possible to alter the so-called natural trajectory as discussed below.

Improve your IQ as well as your general intelligence

First and foremost, it has been shown that fluid intelligence is more difficult to improve relative to crystallized intelligence. This is so because fluid intelligence is thought to be largely innate and reflects your ability to solve problems that you should never have encountered before. Unlike studying for an exam (which makes higher use of crystallized intelligence, and the left hemisphere of the brain) for which you know broadly what materials may be tested, there is limited scope for teaching someone how to be able to react more effectively to never-before encountered situations. What would the curriculum of this course look like? If fluid intelligence is assessed by measuring someone’s ability to solve novel problems, it clearly would make no sense to have a training session to prepare the student on how to solve the problems that are likely to be encountered on such a test.

But the case for improving your fluid intelligence is not a hopeless one. Enter working memory. Working memory is your mental scratchpad or chalkboard which holds information temporarily while you attempt to solve a particular problem. Training your working memory is one of the few approaches that have garnered some scientific support in respect of your ability to genuinely improve your fluid intelligence. More specific training methods will be discussed on future posts.

All of this said, it is easier to improve your IQ score on fluid intelligence tests (i.e. your IQ score) than it is to genuinely improve your fluid intelligence. You can improve your IQ score on a fluid intelligence test by following these recommended steps:

  1. Practice speed and thinking under pressure: this will help ensure that you don’t lose seconds unnecessarily on a timed fluid intelligence test. Processing speed (Gs) is trainable
  2. Attempt as many different types of fluid intelligence tests as possible as you will then begin to establish patterns in respect of the types of questions that might crop up on these tests. In other words, you are diminishing the surprise element on the test or the novel factor by exposing yourself to more types of situations that are meant to be novel
  3. Take each test more than once, and you will start seeing patterns that you may not have spotted the first time around. Practice effects resulting in improvement of up to 8 IQ points are widely known
  4. Learning new skills has been shown to increase the amount of grey matter in your brain. Learning how to juggle and practicing for at least 30 minutes a day will help your reflexes and processing speed

Again, it is unlikely that the above-mentioned methods will help you in genuinely improving your intelligence, but they will definitely help you improve your IQ score.

Achieving a genuine improvement in crystallized intelligence (and crystallized IQ scores), on the other hand, is much easier.

  1. It has been shown that for groups, each year of additional schooling raises IQ
  2. Read more complex material and stretch yourself
  3. Learning a new language, particularly a complex one with a different alphabet, can also bolster cognition

Lifestyle choices are also critical. I will cover some of these in future posts.

In the meantime, try our fluid IQ intelligence test HERE to get an accurate read of your IQ.

The Flynn Effect IQ gains

Flynn effect IQ gains: higher levels of education could be the cause
Flynn effect IQ gain could be explained in part by greater levels of formal education

In 1984, James R. Flynn made the discovery that that IQs of the American population were increasing at a rate of 3 points per decade. This finding was coined “the Flynn Effect” in the controversial book The Bell Curve. This astonishing finding implied that Americans were increasing their intelligence (i.e. the Flynn effect IQ gain) by nearly 9 points per generation, which is over half of one standard deviation for IQ scores. Zhou and Zao confirmed that the rate of 3pt gain in the USA has continued into the 21st Century. Most scientists agree that this is because of societal factors. In the modern world, the increase in the amount of information that one must absorb and the range of experience that people are likely to go through in life are bound to have some profound impact on the brain and on cognitive ability.

Consider the amount of formal education that people tend to go through today vis-à-vis a Century ago (for instance, nearly 60% of Canadians today undertake undergraduate studies). Also consider the amount of information that you come across on the news, the web and through social media. Although Einstein was said to have an IQ of 160, he never was exposed to nearly as much information as the web-savvy, astute reader of the Financial Times, the Economist and the New Yorker would be today. And because crystallized intelligence is one of the major components of general intelligence, it comes as no surprise that people are in fact increasing their smarts. The Flynn effect IQ gain also persists into adulthood, so that means that people are in fact becoming smarter.

If you thought the USA was a special place, then think again. The Flynn Effect was confirmed globally and it turns out that some countries have been experiencing even faster gain than those recorded in the USA.

The Highest Flynn effect IQ gain nations are as follows:

Netherlands: 6.7

Belgium: 5.8

Canada: 4.6

Norway: 3.2

New Zealand: 2.4

Digging deeper into the data however, the IQ gains are not evenly spread across the distribution of IQs. The largest gains in intelligence are found in the lower half of the IQ distribution and the figures quoted above are most applicable to individuals with IQs centered on the mean of 100 (i.e. the average Joe). At the extreme right of the distribution on the other hand, gains are flat to declining which suggests that people with gifted IQs are not getting the same benefit as people who are intellectually average. The Flynn effect gain is largely benefiting Joe Bloggs. All in all, it might be more accurate to state that the average person is getting smarter.

Because of the Flynn effect IQ gain however, it is critical for people to be taking updated IQ tests that have been normed recently to avoid reporting an inflated score.  In other words, people sitting a 30-year old IQ test dating from the early 1980s would be expected to outperform on that test today relative to taking a brand new IQ test that has been normed recently. Remember that IQ tests are always normed at a particular point in time to reflect a mean of 100.

You can assess your fluid intelligence HERE on our recently normed online IQ test.

Culture-fair IQ test

Culture-fair IQ testing
Fluid intelligence tests are applicable to a global audience

Cattell and Horn distilled global intelligence (G) into two principal components: (1) fluid intelligence or Gf; and (2) crystallized intelligence or Gc.  Fluid intelligence is largely innate and represents someone’s ability to solve novel problems and can therefore be liked to raw processing power or the brain. Fluid intelligence is typically associated with the right hemisphere of the brain (i.e. simultaneous processing). Fluid intelligence peaks in our mid 20s and declines thereafter.

Crystallised intelligence, on the other hand, is associated with the body of knowledge learned in school and through formal education. People with greater schooling will on average have a much higher Gc than those people who have limited formal schooling. Because crystallized intelligence is akin to an accumulated body of knowledge, it is not surprising that Gc peaks in our mid 50s, and begins a slow decline thereafter. Crystallized intelligence is linked to the left hemisphere of the brain (sequential processing).

Most professionally administered tests will be able to measure both types of intelligence. However, different questions and/or tests can be used to measure each type of intelligence. Similarly, in the world of online IQ testing, some tests will be better designed for measuring either Gf or Gc.

From an online testing standpoint (where your audience is global), it would be impossible design a scientific test for Gc that does not suffer from cultural bias – that is, it is not possible to design a culture-fair IQ test for crystallized intelligence when you are testing a global audience. In fact, anything that tests a body of knowledge may favor some groups over others. For instance, a test which asks: “who was the third president of the United States” (Thomas Jefferson is the answer by the way), is a question which is more likely to be answered correctly by American test takers than say, Nigerian test takers. And even then, American history majors may be at a significant advantage in getting this answer right than say, American Psychology majors.

Word definitions or describing certain concepts, also suffers from cultural bias due not only to language fluency problems (i.e. should we be ascertaining French-speakers with questions written in English? Of course not), but also due to the fact that different countries and languages use words in different ways. (e.g. in English, you can say “I love pizza”. But you cannot say “Yo amo Pizza” in Spanish, instead, you would say, “A mi me gusta la pizza”, which essentially means that you like pizza). So a crystallized intelligence test cannot be a culture-fair IQ test.

A Culture-fair IQ test for a global audience

For this reason, fluid intelligence tests are the only types of IQ tests that can be described as ‘culture-fair IQ tests’. Fluid reasoning tests such as our IQ-Brain.com test, Raven’s Progressive Matrices (RPM) or Cattell Culture-fair IIIa tests are based on reasonably abstract picture sequences and missing patterns. It can perhaps be argued that knowledge of geometry (or lack thereof) can induce a cultural bias, but it remains that a triangle is a triangle (3 sides, and internal angles totaling 180 degrees) in every nation on earth.

When it comes to testing the IQ of a global internet audience, a culture-fair IQ test is the only kind of test which has scientific merit to ascribe rankings between different nations (i.e. you can administer the exact same test to everyone, with only the instructions requiring translation), and the only types of culture-fair IQ tests that exist will test Fluid intelligence (Gf), which includes Visual Processing ability (Gv), Processing Speed (Gs) and Working Memory (Gsm). Gv, Gs and Gsm are all sub components of fluid intelligence.

Take our culture-faire IQ test HERE.

The different types of intelligence

Raymond Cattell observed different types of intelligenceThere is no hard and fast consensus in the academic literature about how many different types of intelligence exist. In the early twentieth Century, the English psychologist Charles Spearman observed that a general factor (G or g factor),  served to explain much of the consistency in baseline performance of an individual across a multitude of intelligence tests. In simple terms, the g-factor could therefore be likened to a global or general intelligence. The higher someone’s G, the better they were likely to perform across a variety of IQ tests, even though each of these might measure a different aspect of human intellect. Spearman also believed that people possess specific or special abilities, but that G was more closely related to the concept of general intelligence. Spearman could therefore be viewed as a proponent of the single, global IQ score.

Cattell proposed two different types of intelligence

Spearman’s doctoral student Raymond Cattell in the 1940s decomposed his mentor’s theory of G into two principal components: (1) Fluid Intelligence (Gf); and (2) Crystallized intelligence (Gc). Fluid intelligence represents an individual’s ability to solve ‘novel’ or new problems. Crystallized intelligence on the other hand, is the aspect of human intelligence that can be learned in school. So Gf can be likened to raw processing power of the brain, while Gc is closer to a body of knowledge. This is often known as Gc-Gf theory.

Cattell’s theoretical foundation of human intelligence did not gain prominence until the 1960s, when his doctoral student John Horn decided to re-popularize his mentor’s forgotten Gc-Gf theory.  This theory was eventually merged with that of John Carroll, which resulted in what is widely known as CHC theory of cognitive abilities.

CHC theory further dissects G, and Gf-Gf to include seven broad abilities including:

Gc-related sub-indexes:

  • Quantitative reasoning (Gq)
  • Reading and writing ability (Grw)

Gf-related sub indexes:

  • Short-term memory (Gsm)
  • Long-term storage and retrieval (Glr)
  • Visual processing (Gv)
  • Auditory processing (Ga)
  • Processing speed (Gs)

CHC is today the most widely accepted theory of intelligence with several of the major professional IQ tests having been reviewed to incorporate test items to measure several of these broad abilities. Well-known tests such as the Stanford-Binet V and Weschler Adult Intelligence Scales IV typically incorporate four of the seven broad abilities:

Factor indexes (different types of intelligence) of WAIS-IV:

  • Verbal comprehension index (Gc)
  • Perceptual reasoning index (Gv / Gf)
  • Working memory index (GSm)
  • Processing speed index (Gs)

Glr and Ga may be difficult to measure in a short IQ test. Nonetheless, it becomes clear that there are different types of intelligence.

Although G is perhaps an overly simplistic concept, it still resonates in society with the global IQ score being given significant consideration. However, it is important to realize that Global intelligence can be decomposed into different types of intelligence as shown above.

Click here to get an assessment of your Fluid Intelligence (Gf).