Intelligence Quotient

Definition about Intelligence Quotient (IQ)

Intelligence Quotient (IQ) stands for intelligence quotient, which is a standard number that shows how far below or far above your peer group is the mental capacity of your individual. The intelligence quotient (IQ) is the complete number derived from various standardized tests designed to measure human intelligence. 

In the past, the IQ was a result of dividing a person's intelligence test by the chronological age of a person, stated in terms of both years and months. To achieve the IQ scoring, the resultant fraction (quotient) was multiplied by 100.  

Nowadays, the raw score is converted into a normal distribution for current IQ tests, mean 100 and standard deviation 15. This results in around two - thirds of IQ 85 and IQ 115 people and around 2.5 percentage points above 130 and below 70.


Intelligence has been defined in various ways: the capacity for logic, ability to comprehend, self-consciousness, learning, emotional knowledge, reasoning, planning, creation, critical thinking, and problem-solving. It may be characterized more generally as the capacity to receive and infer information and retain this as knowledge used in an environment or context for adaptive behaviors.

Scientist Howard Gardner identifies nine categories in his theory of multiple intelligences: 

  • Linguistic intelligence: reading, writing, listening and speaking skills; 

  • Spatial intelligence: the ability to orient yourself in space. Mentally rotating objects are widely utilized inquiry kinds or forms discovery. Through spatial reasoning, your spatial intelligence may be increased;

  • Logic-mathematical intelligence: the ability to calculate, solve logical puzzles, reason and think scientifically; In verbal, numerical, and geographical inquiries, logical questions or the question of drawing the appropriate conclusions might be included;

  • Musical intelligence: singing skill, playing an instrument of music, analyzing music and composing music; 

  • Bodily-kinesthetic intelligence: the ability to  move your body in a coordinated manner, – for example in dancing, in sports, or in surgical procedures. 

  • Interpersonal intelligence: the ability to comprehend and to interpret verbal and nonverbal conduct among people;

  • Intrapersonal intelligence: the ability to reflect on and comprehend your actions and comprehend them.

  • Naturalist intelligence: the ability to identify and classify natural items; 

  • Existential intelligence: the ability to identify one's own stance about human existential characteristics such as death and the meaning of life.

In Gardner theory, only the three initial intelligence categories overlap with the intelligence typically characterized and evaluated in IQ tests. The notion of a G factor (explained below), which presupposes that there is only one basic component, is at odds in terms of many intelligences.

Moreover, according to Triarchic Theory (Robert Sternberg) intelligence comes in three forms:

  • Analytical intelligence: The ability to acquire and store information; to retain or retrieve information; to transfer information; to plan, make decisions, and solve problems; and to translate thoughts into performance

    • How efficiently people process information

    • How to solve problems, how to monitor solutions, and how to evaluate the results

    • The use of strategies, acquiring knowledge

    • Students high in analytical intelligence do well in class with lecture and objective tests. They are considered smart, get good grades, do well on traditional tests, and go to competitive colleges.

  • Creative intelligence: The ability to solve new problems quickly; the ability to learn how to solve familiar problems in an automatic way so the mind is free to handle other problems that require insight and creativity

    • How people approach familiar or novel tasks

    • Compare new information with what they already know and to come up with new ways of putting facts together

    • To think originally

    • Students high in creative intelligence might not conform to traditional schools. They tend to give unique answers for which they might get reprimanded.

  • Practical intelligence: The ability to get out of trouble; The ability to get along with other people

    • How people deal with their environment

    • How to size up a situation and decide what to do – to adapt to it, to change it, or to get out of it

    • Students high in practical intelligence don’t relate well in traditional schools. They do well outside the classroom walls with good social skills and common sense.

Intelligence and IQ

Intelligence and IQ are different. Intelligence has been defined in various ways: the capacity for logic, ability to comprehend, self-consciousness, learning, emotional knowledge, reasoning, planning, creation, critical thinking, and problem-solving. It may be characterized more generally as the capacity to receive and infer information and retain this as knowledge used in an environment or context for adaptive behaviors. 

Plus, the Q is 'quotient' in IQ.  You have no fixed IQ, but your IQ shows how well you do compared with other people. For example, you may have extremely low IQ, when compared to Albert Einstein or Stephen Hawking, but you would have a much higher IQ compared to certain 4-year-old children. Consequently, your IQ is a score in comparison with one group. This group is defined as an average of 100. Therefore, we used the term 'quotient.' And this is why IQ is really not the same thing as intelligence. 

To put it simply, IQ measures (a number) the 'intelligence' feature that everyone in comparison with others has to a greater or lesser degree.

Intelligence Quotient Test - IQ Test

1. The overview of IQ test

This acronym IQ was developed in a 1912 book (bottom for the German period Intelligenzquotient) by the  scientist William Bottom, who supported his era for the power test rating method in the University of Breslau.

The many different kinds of IQ tests include a wide variety of item content. Certain exam elements are visual, while several are spoken. Test items range from abstract reasons to focus on mathematics, linguistics, or general knowledge. 

2. "g" factor

The first formal factor analysis for the correlations between tests was made in 1904 by the British psychologist Charles Spearman. He noted a positive connection between children's school grades over apparently unrelated topics and reasoned that these correlations represented the impact of the underlying general mental capacity in all forms of testing. 

He argued that all mental performance may be characterized according to a single component of general ability as well as several narrow task-specific capability components. Spearman has called it "g" for "generic factor"  (also known as general intelligence, general mental ability or general intelligence factor) and has identified the particular factors or skills for certain tasks. 

This variable aggregates positive correlations between distinct cognitive tasks, demonstrating the fact that the performance of an individual for one sort of cognitive activity is usually comparable with the performance of an individual in other types of cognitive activities. 

The “g” factor usually accounts for between 40 and 50% of interpersonal performance disparities on a specific cognitive test and composite values ("IQ scores") based on several tests are often seen as estimations of the status of persons with a g factor. 

The score that measures "g" is the highest composite score, with the highest correlations to all questions, in a broad range of research items that constitute an IQ test. In general, a composite "g-loaded" score from an IQ test battery appears to have an abstract power over the substance of the test items.

Raymond Cattell, Charles Spearman's pupil, rejected the unitary g factor model and split g into two wide, generally independent domains: fluid intelligence (Gf) and crystallized intelligence (Gc). Gf is developed to examine unique issues and is most likely to be evaluated with tests with little cultural and/or academic content like Raven's matrices. Gc may be seen as a consolidated knowledge that reflects the skills and information a person obtains and maintains over his lifetime. 

Gc relies on education and other types of acculturation, and examinations emphasizing scholastic and cultural knowledge are best evaluated. Gf consists largely of present thinking and problem-solving ability, whereas Gc reflects the results of earlier cognitive processes.

3. Kinds of test

In the English-speaking world, a number of individually conducted IQ tests are used. The Wechsler Adult Intelligence Scale (WAIS) for adults as well as the Wechsler Intelligence Scale for Children (WISC) for students of school age is the most common kind of tests. The Stanford-Binet Intelligence Scales, Woodcock-Johnson Tests of Cognitive Abilities, the Kaufman Assessment Battery for Children, the Cognitive Assessment System, and the Differential Ability Scales  are also widely used in individual IQ tests (some of which don't have their standard scores as IQ scores). 

A person's IQ can be calculated by having the person take an intelligence test. The average IQ is 100. If you achieve a score higher than 100, you are smarter than the average person, and a lower score means you are (somewhat) less smart. 

An IQ informs you what your result is on a special exam, frequently compared with your age group. This test has a mean 100 point rating and a standard 15 point variance. So what does this standard deviation mean?  It indicates that normally IQ values are distributed, meaning that 95% of the population has IQ scores between 70 and 130. There are nonetheless some extreme cases of individuals with scores much above 130 or much lower than 70. However, another question comes to our mind, when your IQ is 100, what does it mean? Half of the population therefore scores higher than you. The left portion is less than you. And when you have an IQ of 130, what does this mean? That means 97.5 percent of your age group is below your age. The score is only 2.5 percent on average higher.

4.Flynn effect

Another interesting point is that research has revealed a remarkable phenomena, which is termed the Flynn effect, after the researcher who documented this occurrence. On average, international IQ test scores have grown over time: newer folks do better than older ones. The IQ test results improve by an average of 10 points every generation. So in 1950 individuals seemed to be much less intelligent than they are now if you define intelligence in IQ ratings. How can we do that? According to the Flynn effect theory, development in education and improved nutrition can be partly attributed to the growth of IQ values.

Factors Influencing Intelligence (and IQ test)

1. The Child’s Influence:

  • Genetics

  • Genotype–Environment Interaction

  • Gender

    •  Boys and girls tend to be equivalent in most aspects of intelligence

      • The average IQ scores of boys and girls is virtually identical

      • The extremes (both low and high ends) are over- represented by boys

    •  Girls as a group:

      • Tend to be stronger in verbal fluency, in writing, in perceptual speed (starting as early as the toddler years)

    • Boys as a group:

      • Tend to be stronger in visual-spatial processing, in science, and in mathematical problem solving (starting as early as age 3)

2. The Immediate Environment’s Influence

  • Family Environment

  • School Environment

    • Attending school makes children smarter

      • Children from families of low SES and those from families of high SES make comparable gains in school achievement during the school year

    • What about during summer break?

      • During the academic year -- schools provide children of all backgrounds with the same stimulating intellectual environment.

      • Over the summer, children from low-SES families are less likely to have the kinds of experiences that would maintain their academic achievement.  

3. The Society’s Influence

  • Poverty

    • The more years children spend in poverty, the lower their IQs tend to be

      • Children from lower- and working-class homes average 10-15 points below their middle class age mates on IQ tests

    • In many countries, children from wealthier homes score better on IQ test than children from poorer homes

      • The greater the gap in wealth in a country the greater the difference in IQ scores

    • Chronic inadequate diet can disrupt brain development

      • Chronic or short-term inadequate diet at any point in life can impair immediate intellectual functioning

    • Reduced access to health service, poor parenting, and insufficient stimulation and emotional support can impair intellectual growth

  • Race/Ethnicity

    • Overall, differences in IQ scores of children from different racial and ethnic groups describe children’s performance ONLY in the environments in which the children live. These findings do not indicate potential, nor do they tell us what these children would do if they live someplace else. The current group differences in IQ are due to environmental differences -- as discrimination and inequality decrease -- IQ differences decrease.

    • The average IQ score of Euro-American children is 10-15 points, which is higher than that of African-American children

    • The average IQ score of Latino and American-Indian children fall approximately between those of Euro-American and African-American children

    • The average IQ score of Asian-American children tend to be higher than any other group in the US

    • American-Indian children: Better on the performance part than the verbal part of an IQ test

    • Latino children: Better on the performance part than the verbal part of an IQ test

    • Asian-American children: Better on the performance part than the verbal part of an IQ test

    • African-American children: Better on the verbal part than the performance part of an IQ test