Intelligence: Theories, Measurement and Development

1. Intelligence in Psychology

Intelligence is one of the first objects of study in psychology. Its definition and complexity are still debated, and it remains a multidisciplinary research topic.

Classic Theories

• Galton applied innate methodology and statistics to intelligence.
• Spearman proposed a two-factor theory and used factor analysis. He identified a general factor (g) and specific abilities.
• Thurstone identified seven primary mental abilities: verbal comprehension, verbal fluency, numerical ability, memory, perceptual speed, spatial visualization and inductive reasoning.
• Guilford proposed a three-dimensional model of intelligence: operations (mental processes), contents (types of information) and products (the form the information takes). He also distinguished multiple aptitudes, including divergent and convergent thinking.

Evaluation of Intelligence

Intelligence tests are instruments built to measure intelligence. Individuals are asked a series of questions or tasks, and their answers are compared with those of a reference group to determine their level of ability.

Intelligence Tests

• Binet: the first intelligence scale, based on mental age, the level of performance expected for children of a given chronological age.
• Stern: introduced the intelligence quotient (IQ).
• Stanford-Binet: an adaptation that measures verbal, numerical reasoning, abstract reasoning and memory.
• WAIS-R (Wechsler): one of the most widely used tests in school settings.

Characteristics of Tests

Tests do not directly measure intelligence. Their indicators must be interpreted using statistical treatment, and raw scores are not directly comparable, so they must be converted into typical scores. All good tests must have validity and reliability.

Limitations of Tests

• There is no agreement on how intelligence should be measured.
• Although they are good predictors of academic learning, they only cover one area of human thought and do not study cognitive processes.
• Creativity is not included.
• They do not take culture into account.

2. Development of Intelligence (Piaget)

Piaget's constructivist theory holds that the child builds their own cognitive structures through maturation and experience.

Key Concepts

• Scheme: a sequence of actions that can be repeated and applied to similar situations. Schemes change from innate reflexes to symbolic actions and operations.
• Adaptation: intelligent adjustment to the environment, based on assimilation and accommodation, which produce balance.
• Accommodation: the change of schemes during adaptive periods.
• Organization: thinking works as an organized whole.
• Stage: thinking is organized into structured cognitive stages. Maturation allows progression from one stage to the next.

Cognitive Development Stages

Sensorimotor intelligence (0-2 years): the child knows the physical and social world through sensory systems (vision and hearing) and motor actions. Innate reflexes become organized habits, paving the way for sensorimotor intelligence.

Preoperational intelligence (2-6 years): the emergence of representational thinking, language development, search for order and perseverance, and egocentrism.

Concrete operations: mental operations on concrete objects, classification of objects and sensation.

Formal operations: abstract thinking, construction of theories, development and testing of hypotheses, and deductive reasoning.

3. Current Theories

1. Information Processing Theory

   Based on the work of Sternberg, this approach analyzes the manipulation of information through mental operations. Intelligence is formed by three aspects: componential intelligence (information processing capacity), experiential intelligence (ability to face new situations) and contextual intelligence (adaptation, modification or selection of the natural environment).

2. Emotional Intelligence

   The ability to understand and manage one's own and others' feelings, including impulse control, self-awareness, mental agility, etc.

3. Multiple Intelligences

   Gardner rejects the single-intelligence view and proposes eight relatively autonomous intelligences that can combine: linguistic, logical-mathematical, musical, spatial, bodily-kinesthetic, naturalistic, interpersonal and intrapersonal.

4. Problems of Intelligence

There are two main positions: hereditarians and environmentalists (heredity versus environment). Determining whether intelligence is hereditary or environmental is problematic, and programs are needed to support the development of intelligence in culturally disadvantaged groups. Intelligence has no color, and no group should be blamed for school failure.

Modifiers of Intelligence

Moving beyond the heredity-environment debate, environmental approaches hold that cognitive enrichment can improve the intelligence of individuals. Examples include the Instrumental Enrichment Program (IEP) and Harvard's Project Zero, which developed programs for children.

Artificial Intelligence

Artificial intelligence attempts to solve problems and is inspired by how the human mind functions. Its five main areas are: symbolic reasoning, neural network operation simulation, natural language processing, artificial vision and robotics.