Intelligence is the ability to learn from experience, solve problems, and use knowledge to adapt to new situations. It is among the most studied and most debated constructs in psychology.

Psychometric approaches emphasize a general factor, g, that influences performance across diverse cognitive tasks, along with more specific abilities. Multiple-intelligence theories propose distinct forms of intelligence—linguistic, spatial, interpersonal, and others—that can vary independently. Cognitive approaches analyze the component processes of reasoning, memory, and speed. Emotional and practical intelligence extend the concept beyond academic problem solving.

Intelligence tests predict educational and occupational outcomes with moderate success, yet they do not capture every valued human capacity. Scores are influenced by genes, environment, culture, and test construction. Group differences exist and remain controversial; within-group variation is always larger than between-group averages. The question of what intelligence “really is” continues to generate both scientific research and public argument.

Whatever the definition, the capacity to learn, reason, and adapt remains central to how individuals navigate a complex world.