The present paper describes the Flynn effect, understood as the gains observed in measures of intelligence over time. To facilitate the understanding of the effect some ideas about psychometric intelligence are presented, especially those that suggest a hierarchical organization of cognitive abilities, differing more general factors over specific factors associated with learning. The Flynn effect tends to be more consistently observed in tests of general intelligence and fluid intelligence. Possible causes of the Flynn effect and the abilities in which it is most likely to manifest itself are also presented and discussed.
Intellectual gains; Intellectual quotient; General factor; Tests