LAUSR

Abstract In three rural Ecuadorian schools from different regions (central highlands in the Andes, hinterland of Quito, and Amazonian lowlands) N  = 161 pupils aged 9–14 with about 86% Amerindian background were tested for cognitive ability. Fluid intelligence was measured using culture-reduced Raven's SPM, while crystallized intelligence was measured using school-near tasks from PIRLS-Reading and TIMSS-Mathematics. Parental education, parental wealth (family assets), number of books in the home, parenting style, discipline in school, and height (relative to age and sex) were also measured. Average IQ using British FLynn-corrected 1979 SPM norms was equal to 71, with the figure being lower in the central highlands (IQ = 65) than in the hinterland of Quito and the Amazonian lowlands (IQ = 75). Raw performance only weakly increased with age ( r  = .11 to .18) indicating limited cognitive development and resulting in lower normed IQs at higher ages ( r  = −.17 to −.22). Individual differences in cognitive ability were better explained by parental education ( β Ed  = .53 to .54) than by parental wealth ( β We  = .14 to .15). Height per-age-and-sex had an effect of β He  = .13 to .14. Number of books, discipline and authoritative parenting also had positive impacts. Explanations for the low average performance and for differences between regions are discussed.