What is intelligence?
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Understanding Intelligence: Definitions, Components, and Influences
General Intelligence and IQ Tests
General Intelligence (g) and Heritability
Intelligence is often measured through IQ tests, which are interpreted as measures of general intelligence or "g." This general intelligence is considered a heritable component that influences the acquisition of knowledge and cognitive abilities. Intelligence is not static; it changes over the lifespan, typically declining with age. The congruence between IQ phenotype and genotype increases as one ages, indicating a stronger genetic influence over time.
Influence of Education and Environment
Intelligence development requires exposure to formal education and is influenced by cohort-specific exposures. Despite these influences, intelligence is relatively stable and significantly impacts educational performance and occupational status.
Cognitive Functions and Brain Networks
Mental Abilities and Cognitive Functions
Intelligence can be defined as a general mental ability encompassing reasoning, problem-solving, and learning. It integrates various cognitive functions such as perception, attention, memory, language, and planning. Standardized tests can reliably measure intelligence, and the scores predict several broad social outcomes, including educational achievement, job performance, health, and longevity.
Neurobiological Basis
Research indicates that a frontoparietal network in the brain is relevant for intelligence. This network also underlies cognitive functions related to perception, short-term memory storage, and language, highlighting the integrative nature of intelligence. Current research is focusing on how functional networks relate to structural networks in the brain, emphasizing the communication between distributed brain areas.
Conceptual Frameworks of Intelligence
Multiple Definitions and Concepts
Intelligence is a complex concept with multiple definitions. One approach defines intelligence as a person's unique information about a category, with different individuals having varying knowledge about the same category. This approach identifies three major concept/category pairs of intelligence: Spearman's g, intelligence as a property of behavior, and intelligence as a set of abilities.
Prototypical Intelligence
Another perspective suggests that intelligence is the degree to which one resembles a prototypically intelligent person. This implies that no single characteristic defines intelligence, and a combination of many empirically derived measures is necessary to form a comprehensive understanding. This view aligns with the idea that intelligence is what works best for an individual in adapting to their environment.
Intelligence Across the Lifespan
Adaptation and Lifelong Learning
Intelligence involves the mental abilities necessary for adaptation to, and selection and shaping of, any environmental context. Although the behavior labeled as intelligent may differ across contexts, the underlying mental processes remain consistent. This adaptability is crucial for lifelong learning and success.
Age-Related Changes
Intelligence varies across the lifespan and generations. It is partly understood in terms of brain biology, particularly the prefrontal cortex's functioning. Heritability studies suggest that genetic factors significantly influence intelligence, although this influence varies with socioeconomic status and other factors. As people age, their intelligence may qualitatively change rather than decline, reflecting their adaptation to new life roles and environments.
Conclusion
Intelligence is a multifaceted construct that encompasses general mental abilities, cognitive functions, and adaptability to various environments. It is influenced by genetic and environmental factors and changes over the lifespan. Understanding intelligence requires considering multiple definitions and conceptual frameworks, as well as the neurobiological underpinnings that support cognitive functions. This comprehensive view of intelligence highlights its complexity and the various factors that contribute to its development and manifestation.
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