What is intelligence?

The concept of intelligence is difficult to describe. One way, is to describe intelligence through three levels of analysis:

1. Some see intelligence as one factor called general intelligence, g. General intelligence are cognitive processes influencing the ability to think and learn on all intellectual tasks.
2. There are also good arguments for intelligence to consist of two types of intelligence, fluid intelligence and crystallized intelligence. Fluid intelligence is the ability to solve new problems at a certain moment, for example by drawing conclusions and understanding relationships between concepts that have never been encountered before. Fluent intelligence usually peaks in early adulthood and then slowly decreases. Crystallized intelligence is the actual knowledge about the world. Crystallized intelligence starts early in life and continues to multiply. Thurstone divides intelligence in a complex way into seven skills. These are the so-called seven primary mental abilities crucial for intelligence: word fluency, verbal meaning, reasoning, spatial visualization, numbering, rote memory and perceptual speed. The division of intelligence into seven abilities equals the distinction between fluid and crystallized intelligence. Some scores on certain abilities correlate more with each other than with scores of other abilities.
3. The third view sees many different processes involved in intelligence. This leads to more specification of processes in intellectual behavior than the other two levels.

The perspectives can be brought together. According to Carroll, there is a model for intelligence: the three-stratum theory of intelligence. This model contains general intelligence in the top layer of the hierarchy, then several moderately general abilities in the middle layer, and at the bottom layer numerous specific processes. In short: all three levels are necessary to understand and measure intelligence.

How can intelligence be measured?

Measuring intelligence is difficult because it is an invisible capacity. Measuring observable behavior is the only way to measure intelligence. For different ages, there are several tests to measure intelligence. The Wechsler Intelligence Scale (WISC) is used for children from six years and older. The design that underlies the WISC-V is consistent with Carroll's three-layer theory.

What is the intelligence quotient?

In most intelligence tests, a general quantitative measuring instrument is used to measure the intelligence of a child. Like this it is comparable with other children of the same age. It is called the Intelligence Quotient (IQ). Many characteristics, including intelligence, are normally distributed. This normal distribution is a pattern of data in which scores fall around the average, with most scores being close to the average and scores that occur less frequently far from the average. The average of the intelligence quotient is 100, where the standard deviation is 15. A standard deviation (SD) is a measure of the variability of scores in a normal distribution. In a normal distribution, 68% of the scores within 1 SD fall from the average, and 95% of the scores fall within 2 SD of the average. The older a child gets, the higher the scores will be on intelligence tests.

Which factors can influence the IQ score?

There are certain aspects influencing the intelligence tests: the alertness (for example if you have slept little, you are less alert), the knowledge of the tests (for example if you do not understand the test procedure, you will score worse), and environmental factors (for example if you have just moved or your parents are just divorced).

What outcomes can be predicted by intelligence?

There are several things that can be predicted on the basis of the intelligence quotient. IQ scores are a strong predictor for academic, economic and, work-related successes. If you have a high IQ score, there is a big chance that later you will earn more, perform better at school and get promoted more often.

However, additionally to IQ scores there are other predictors that lead to success like the motivation to succeed, awareness, creativity, physical and psychological health and social skills. Self-discipline is a stronger predictor of scores than the IQ score. Self-discipline is the ability to inhibit actions, adhering to the rules and avoiding impulsive reactions. Practical intelligence is the mental possibility not measured by intelligence tests, but important for success in many situations. Such as being able to read other people's emotions and intentions and motivating others to work together effectively.

There are examples of 'gifted children' that score exceptional in different intellectual areas. The talents are often seen very early in the development. Exceptional qualities are often a pre-announcement of exceptional performance later in life.

What are the influences of genes and environment on intelligence?

There is a great debate about the factors that influence intelligence. To reflect on the genetic and environmental influences, a useful starting point is the bio-ecological model of Bronfenbrenner. This model represents the life of a child embedded in a series of increasingly comprehensive environments. The child is in the middle, surrounded by the immediate surroundings, which is surrounded again by the general environment.

How do the characteristics of the child affect intelligence?

The genome has a great influence on intelligence. This influence increases with age. The correlations between individual alleles of genes and IQ are very small, which shows that genetic influences on intelligence consist of all small contributions from many different genes and interactions between these genes.

The environment is influenced by the genotype. This can have different effects: passive, evocative, and active effects. Passive effects of the genotype arise when children are raised by their biological parents because of the overlap in genes between the parents and the child. Evocative effects of the genotype arise when children influence someone else's behavior. Active effects of the genotype arise when children choose their own environment that they like.

How does the immediate environment affect intelligence?

The immediate environment also affects the intelligence of a child. A measuring instrument has been designed to measure the influence of the home environment: the HOME (Home Observation for Measurement of the Environment). This measuring instrument measures various aspects of a child's home situation, such as the organization and safety in the home, the intellectual stimulation by the parents, whether children have their own books, the degree of parent-child interaction and the emotional support that children receive from their parents. It has been shown that the measurements of HOME correlate positively with the IQ scores. The environment of the family (HOME) is also a good predictor for the IQ of a child.

Going to school also makes a child smarter. Through education specific cognitive skills are improved.

How does society influence intelligence?

The wider environment (or society) also influences the intelligence of a child. In many countries, the average IQ scores increased over the last 80 years. This is called the Flynn effect. . A possible explanation for the Flynn effect could be the emergence of new technologies such as video games. Playing video games has been associated with improvement in executive functioning, problem solving, selective attention, and reading, writing, and math skills; so fluid intelligence in general.

Poverty in certain countries can have a major impact on intelligence. People living in a poor population generally have a lower IQ compared to the richer population. Because people in poverty eat little or even skip meals, brain development is influenced and also intellectual functioning in everyday life is affected.

There are influences of differences in race and ethnicity. A study showed that the average IQ scores of children from different races and ethnic groups are indeed different. Namely, the average IQ score of European-Americans is about ten points higher than the average IQ score of African Americans. These differences refer to group differences in IQ scores and not to individual differences in IQ scores. There is much more variability within a race or ethnic group than between the groups. The third fact is that the differences in IQ and achievement of test scores are only described as the performance of the environment in which the child lives. In other words: the scores do not show the potential intelligence, nor do they reflect what had happened to the children's intelligence if they had lived in a different environment.

There are always different risk factors that can lead to a low IQ score. The environmental risk scale measures ten characteristics giving children a risk for low IQ scores. The more characteristics are present, the more risk a child runs. The risks that arise from poverty can be compensated by a high-quality education.

Research of interventions designed for underdeveloped families show a consistent pattern. Initially, the IQ of the children participating in the intervention becomes higher, but then the IQ decreases. Fortunately, it has also been found that fewer participants ended up in special education. This is apparently not due to an increase in the IQ, but probably due to the intervention's long-term effects on the motivation of the child.

The Head Start program is offered to many children. Children who participated in this program showed better pre-reading and pre-writing skills, improved social skills, better health, they where more likely to finish high school and had a lower risk at drug use.

The Carolina Abecedarian Project is a comprehensive and successfully enriching program for children from low-income families. Children entered the program at the age of 6 months. It is based on seven principles: (1) stimulating exploration, (2) guiding basic skills, (3) celebrating advances in development, (4) repeating and generalizing new skills, (5) protecting children from inappropriate disapproval, bullying and punishment, (6) communicating richly and responsively, and (7) guide and limited behavior. This program proved to have lasting positive effects on the IQ and on performance in reading and mathematics. This program shows that it is important to start early with interventions, that caregivers must communicate in a positive, responsive manner with the children, that the improvements are probably mainly due to improvements in self-control and perseverance, and finally it showed that there are possible interventions having lasting positive effects on the intellectual development of children who grow up in poverty.

What are alternative perspectives on intelligence?

Some aspects are measured by the IQ test: verbal, mathematical, and spatial skills. However, other aspects are not measured by the IQ test: creativity, social insight, knowledge about own weaknesses and strengths, etc. This led to the development of a theory that is broader than the traditional theories about intelligence. Namely the multiple intelligence theory, designed by Gardner. This theory is based on a perspective that people have at least eight types of intelligence: the linguistic, arithmetical, and spatial skills already measured in traditional theories of IQ testing, but also the musical, naturalistic, physical, interpersonal, and intra-personal skills.

Sternberg also criticizes the traditional theories of IQ testing. Yet his theory differs from that of Gardner. Sternberg’s theory of successful intelligence is based on a perspective that sees intelligence as an opportunity to become successful in life. According to Sternberg, there are three types of skills that can lead to success in life: the analytical, the practical, and the creative skills. The analytical skills include language, arithmetic, and spatial skills measured by traditional IQ tests. The practical skills contain reasoning about daily problems, such as solving conflicts with other people. Creative skills include intellectual flexibility and innovation, which lead to effective reasoning in new circumstances.

How do children acquire academic skills?

How do reading skills develop?

Reading develops in five stages:

• Stage 0: from birth to group 3. Here the alphabet and phonemic awareness is learned. The phonemic awareness is the ability to identify sound components into words.
• Stage 1: children in groups 3 and 4. Here, children set up phonological recoding skills. These are skills to translate letters into sounds and to mix sounds in words. This is also called 'sounding out'.
• Stage 2: children in groups 4 and 5. Here children learn to read simple texts fluently.
• Stage 3: children from the 6th group to the 2nd class. The children become skilled enough to obtain complex, new information from written text. As Chall says, "children learn to read in the lower classes, but in the higher classes children read to learn."
• Stage 4: 2nd class to 6th class. Here children learn to understand information from multiple perspectives, rather than from a single perspective.

Before children go to school, they already acquire basic information about reading. Things like having to read from left to right and from top to bottom. Phonemic perception is correlated with reading performance later in life and it is also a cause of it. It appears to be a stronger predictor than IQ or social class. Children with a larger phonemic sensation read more and better, which in turn leads to an even greater phonemic perception and improvement in the quality and quantity of reading.

Words can be identified in two ways: phonological recoding and visually based retrieval. The visually based retrieval is a procedure in which the meaning of a word is directly derived from the visual form of a word. Most young children use both approaches to identify words. From group 3 on, the child usually chooses the way that is most suitable for a specific situation. This is called strategy choice process.

According to the simple view of reading, reading comprehension is determined only by the ability to decipher and the understanding of oral language. The ability to decipher words is the best predictor of text comprehension in elementary school; Listening comprehension is an even better predictive factor from the upper years of primary school. To understand a text, a mental model is formed of the situation or event that is continuously updated while reading the text. Basic processes such as encoding, and automation are crucial for reading comprehension. Comprehension monitoring helps to distinguish good and bad readers. Therefore, one looks at the understanding of a text. The path to good or weakly reading comprehension starts before children go to school, for example by listening to told or read stories. If children can read for themselves, the more they read, the better their reading comprehension.

Dyslexia is the inability to read and write well, despite having normal intelligence. The cause of dyslexia is not entirely known, but it is clear that genes play a role. Dyslexia is mainly due to a weak ability to discriminate between phonemes, weak short-term memory for verbal material, a limited vocabulary and a slow recall of the names of objects. Determining which sound belongs to which vowel is difficult for children with dyslexia. Problems often persist in adulthood. In children with dyslexia, two areas of the brain are less active than in children without dyslexia. One area is involved in discriminating between phonemes and the other in integrating visual and auditory information. The best interventions improve the reading comprehension of dyslexic children by increasing their vocabulary and by teaching them more general knowledge about the world.

How do writing skills develop?

Even before children go to school, they try to write. This indicates that they expect that there is a meaning in a print. The collecting of strategies contributes to improvements in writing. A well-known strategy is organizing a sequence of goals, also called a script: a sequence of actions used to organize and interpret repeated events (such as eating in a restaurant and writing a report). Metacognitive understanding plays a crucial role in writing. The most basic form of metacognitive understanding is to be aware of the fact that the readers may not have the same knowledge as the writer. Therefore, a text must contain all the information necessary for the reader to fully understand the text. Another important type of metacognitive understanding is that a writer must have a plan before he / she actually starts writing a text. Good writers spend much more time planning before they actually start writing. Finally, knowledge of the content is an important factor in writing. Familiarity with a topic creates better written documents.

How do math skills develop?

There is a wide variety of strategies used to solve problems. Children start counting at a young age. Later children use different strategies to solve certain arithmetic situations. Numerical magnitude representations are mental models of the sizes of numbers, arranged along a little-to-more dimension. For example, young children have no idea if 4 is larger than 8 and adults sometimes have no idea if 3/5 is greater than 5/11. These are examples of a lack of accurate representations of numerical sizes. The accuracy of these representations differ with age, which is related to the mathematical knowledge of children. At school, children create arithmetic concepts, such as arithmetic equality. This is a concept stating that the values ​​of one side of a sum must be equal to the other side of a sum by means of the '=' sign. Children can make mistakes in this, such as the so-called gesture-discrepancy, in which the gestures that children make express a different idea than their verbal statements.

Arithmetic knowledge differs per country. These differences can be seen before children go to school and seem to be related to cultural emphasis on mathematics, the quality of mathematics teachers and textbooks and the time spent on mathematics in the classroom and at home. Another important factor is language. In Chinese, Japanese and Korean, for example, numbers are much clearer than in English, making them easier to learn in these languages.

Many children experience a fear of mathematics, a negative emotional state that leads to fear and avoidance of mathematics. This fear can reduce the performance of the working memory, which is necessary to solve mathematical problems. For the children with the fear, it can be helpful to write down their emotions prior to an exam, for example. Although math skills do not differ between boys and girls, math anxiety is more common in girls.

Between 5% and 8% of children perform that weakly in mathematics, that they are said to have a mathematical disorder. These children have average IQ scores. Their performance does improve with age, but even later in life they have difficulty with mathematical skills. In severe cases, brain damage is the cause in areas that are responsible for, for example, the processing of numbers. In other cases, for example, minimal exposure to numbers in early childhood may be the cause. Various interventions are available for improving mathematical skills.