Types of IQ tests
There are slight differences between the different IQ tests that are used nowadays.
We have classified them into 3 different types of tests: Culturally fair IQ tests (aimed at measuring fluid reasoning without the influence of culture), full-scale IQ tests (aimed at measuring IQ through measuring all the different subintellectual abilities that correlate with IQ), and aptitude tests (which do not really aim to measure intelligence, but a general aptitude for something. In some cases, the said general aptitude is strongly correlated with intelligence, which makes them a sort of IQ test).
Today we will explain the main differences between them, when each type should be used, among many other things!
Before diving in, we recommend you have a look at our article about how IQ tests are created, in order to have a deeper understanding of everything.
Without further ado, we can now dive in!
The different types of IQ tests are:
Type 1: Logical matrices: culturally fair IQ tests
Also called fluid reasoning IQ tests. These are non-verbal IQ tests that aim to measure intelligence without the inference of language (and thus without the inference of culture). All the items are of analytical and abstract nature. These items are usually a series of elements that follow a pattern, and the test-taker’s job is to find out the pattern and then based on that indicate what the element that follows is.
These tests are not really aimed at measuring IQ, but fluid reasoning and G. Both IQ and G/fluid reasoning are in reality almost the same, you can check out our other articles in order to find out the differences!
They are much faster to administer than full-scale IQ tests and provide results with almost the same levels of accuracy.
The most representative example of this type of test is the Raven’s Progressive Matrices.
Type 2: Full-scale IQ tests
These tests are aimed at measuring IQ. In the first type of tests, the object being measured is fluid reasoning, which is a sub-task/cognitive ability that presents a very high correlation with general intelligence; they are almost synonymous.
However, remember that there are different cognitive tasks encompassed under the umbrella of general intelligence. IQ tests measure all these different aspects of intelligence, providing a separate score in each of them and a general score computed from all these different subintellectual abilities. That resulting general score is IQ, and it is almost the same as G or intelligence.
These sub-intellectual abilities and tasks include:
- Verbal reasoning
- Numerical ability
- Spatial intelligence
- Working memory
- …among many others
They are mostly extracted from Carroll’s three stratum theory of intelligence.
A good example of this type of tests, and probably the most representative one, is the WAIS (Wechsler Adult Intelligence Scale).
Type 3: Aptitude tests
This type of tests also measures general cognitive ability or performance, but they do so by measuring aptitude and basic skills in different basic areas of human intellectual ability, such as mathematical, linguistic, or spatial realms. They are usually used in HR for recruitment purposes or in educational contexts.
Having said this, you might be wondering what is the difference between this type and the latter.
Well, whilst full-scale IQ tests measure different basic cognitive abilities (eg: mental rotation, recall, etc…), aptitude tests measure general intellectual aptitude by measuring the purely intellectual aptitude of the subject in different basic areas.
As you might have noticed, full-scale IQ tests use cognitive tasks, primary cognitive abilities, in order to infer general intelligence. Aptitude tests, instead of using pure cognitive abilities, use aptitudes in these basic and intellectually primary fields (math, language, and spatial reasoning).
A cognitive ability is a capability of the brain, a task the brain is able to perform, whilst an aptitude is a skill that has been learned. Depending on the skill or knowledge load of the aptitudes to be measured, the correlation of the final score with general intelligence will be higher or lower. The lower the influence of the skill/learning per se, the higher the influence of IQ/intelligence in these sorts of tests.
A good example of a widely known aptitude test is the SAT (Scholastic Assessment Test), which is used in the US by universities, in order to make admissions decisions.
According to research, the correlation between SAT scores and IQ range between 0.53 and 0.82, meaning it is a very intelligence-loaded test.
What type of IQ test is better?
It will really depend. There is not a single type of IQ test that is better in all scenarios. There are many factors that could influence the type of IQ test that should be administered.
One of them would be the use case, that is, the intended purpose of the administration. If the goal is to measure job aptitude, then an aptitude test that takes into account skills that will be used in the said job (eg: numerical skills, statistical skills, etc…) could be the best way to go. If the goal is to measure scholastic performance, then using an aptitude test like the SAT would be ideal. Although the first two types of IQ test could also be used in such contexts.
If the goal is, however, to satisfy someone’s curiosity about IQ, then a culturally fair IQ test/fluid reasoning test would be the best choice. A full-scale test could also be used for such purpose, and it would give more detailed insights (since it also measures the ability of the test-taker in all these aforementioned subintellectual domains), at the expense of a longer administration duration.
The first two types of IQ tests could also be used with diagnostic purposes. For instance, the WAIS is often administered in cases of autism. Both can be used to diagnose giftedness, although the Raven’s provides a very interesting advantage over the WAIS; it can be administered without any time limit (since it has been found that there was no correlation between performance in the said test and the time taken to complete it). This is very useful in some instances, like with patients with anxiety disorders (since worrisome reduces performance) or with patients who simply feel pressured and intimidated by time constraints.
In sum, all of the aforementioned types of IQ tests offer good measures of general intelligence and can be used in a wide variety of contexts. The professional in charge of their administration should decide which one to use depending on each scenario.
Muhammad Ovais is Ph.D. from Chinese Academy of Sciences (CAS), National Center for Nanoscience and Technology of China. His research interests are in Neurodegenerative diseases, Nanomedicines and Biomaterials. He is the recipient of over 30 international awards including, 2019 Outstanding International Researcher by the Ministry of Education, China and 2019 Premium Award for Best Research Paper by IET-Institution of Engineering and Technology, UK. He owns to his credit over 60 scientific articles including research studies, reviews, editorials and book chapters in peer-reviewed journals/publishers such as, Advanced Materials-Wiley, NanoToday-Elsevier, Nanomedicine-Future Medicine, with h-index of 30. He is the co-founder of Synthon Nanotech, a Netherlands based Startup Company developing peptides and also working as a Tech Ethicist for a US based company GenoEmote; that is developing novel Brain-Computer Interface technologies.