A frequent confusion in the world of Psychology: are IQ and intelligence synonymous?
The concept of intelligence quotient, also known by its abbreviation (IQ), is used with enormous frequency as if it were equivalent to intelligence, or at least a definitive measure of this construct. However, IQ and intelligence are not synonymous nor should they be understood as such, despite the close relationship between both concepts.
In this article we will focus on answering a question: is IQ the same as intelligence? For this we will show several definitions of these two terms and we will analyze the relationships and differences that exist between them.
What is intelligence?
The term “intelligere” comes from Latin and can be translated as the ability to understand or perceive. During the Middle Ages the words “intellectus” and “intelligentia” began to be used in a similar way to the Christian concept of the soul.
There are many different conceptions of the construct “intelligence”. Although each one of them highlights different aspects, most agree that it is a relatively stable aptitude that varies depending on the individual and is associated with problem solving and other higher-order cognitive functions , as well as adaptation to environment.
The dictionary of the Royal Spanish Academy includes several relevant factors in its definition of intelligence: the ability to understand and know things (similar to the original Latin word), as well as to solve problems. In addition, one of the meanings describes intelligence as a skill derived from experience.
Albert Binet, creator of the first IQ test, equated intelligence with judgment or common sense. David Wechsler, author of the WAIS and WISC intelligence tests, affirmed that it is a global capacity that allows us to achieve goals, think rationally and face the environment. Charles Spearman, a pioneer in psychometry, also stressed this unitary character.
In contrast , the author of the theory of multiple intelligences, Howard Gardner, defines intelligence as a set of differentiated abilities that allow us to solve problems that arise throughout our lives and acquire new knowledge. We will discuss the perspective of Gardner and other critics of the IC concept later.
Defining intelligence quotient (IQ)
The intellectual quotient or IQ is the global score obtained in various instruments whose objective is to measure intelligence. Its origin is the concept of “mental age”, which comes from the first intelligence scale: the one developed by Binet and Simon to assess the special needs of children with learning difficulties.
The term “IQ” was coined by William Stern, a German psychologist who is an expert in interindividual differences. This author developed the contributions of Binet and Simon: he proposed dividing mental age by chronological age to improve the discrimination capacity of intelligence tests between people of the same age. The result was IQ.
Later Lewis Terman revised the Binet-Simon test adding the concept of IQ proposed by Stern. He also perfected the way of calculating it; multiplying the result of dividing mental age by chronological age by 100 avoided fractions. On the other hand, Terman popularized the abbreviation “CI”.
Wechsler intelligence tests
Today, and since the appearance of Wechsler intelligence tests in the 1950s, IQ is obtained by comparing the scores of a given subject on the test with those of other people of the same age. For this, normal scores with a mean of 100 and a standard deviation of 15 are used.
Following this distribution, two thirds of the population have an IQ that can be considered normal, that is, between approximately 85 and 115. Scores between 75 and 90 denote, according to Wechsler, borderline intelligence, while those between 115 and 130 are slightly high.
The Wechsler tests also stand out because they include not only the total IQ, but also several sub-factors. The two main ones are the verbal and manipulative IQ ; the former is measured with tests of acquired knowledge and verbal comprehension, and manipulative IQ has to do with fluid reasoning and information processing.
The relationship between IQ and intelligence
Today IQ is frequently used in the assessment of different types of people, such as students or applicants for a particular job. In this sense, it is used mainly based on the predictive capacity of fluid intelligence in academic and professional performance.
The most intense correlation at the psychosocial level is that between IQ and grades during basic education; its value is calculated to be approximately 0.50. The ability of IQ to predict job performance varies depending on the job but tends to be lower than academic, probably because its effect is mediated by education.
On the other hand, a very common criticism of IQ tests is ethnocentrism : it is argued that they favor those who have grown up in certain environments (for example in Europe or Japan) to the detriment of intellectual aptitudes that are more appreciated in others. Intelligence is a very broad concept, and it is difficult to avoid reductionism in operationalizing it.
Multiple authors, such as Sternberg and Gardner, have opposed the unitary conception of intelligence that derives from the widespread use of IQ tests. From these perspectives, an extension of the concept of “intelligence” is defended to include capacities related to interpersonal relationships, motor skills, creativity or self-knowledge.
Lev Vygotsky, a key theorist in educational psychology, emphasized the dynamic nature of intellectual abilities, leading to a series of interventions that repeatedly assess progress on IQ-like measures as the corresponding abilities are trained. . This is in contrast to the idea of intelligence as a stable factor.
The IQ should be understood as a fragmentary measure of intelligence that focuses on some domains, such as language or spatial reasoning, while leaving aside others that are also relevant to everyday life. Also, it is important to bear in mind that intelligence can be more modifiable than we think.