A study of effects of age and schooling in grades five and six on raw scores from a variety of general ability tests found that schooling: (1) is the major factor underlying the increase of intelligence test scores as a function of age; and (2) has a larger effect on verbal than nonverbal tests. (RH)

Examined the relationship of environmental input to cognitive growth in language, spatial operations, concepts, and associative memory in children tested four times six months apart and differing in the amount of school input received. Found that children made greater growth over periods with greater amounts of school input for language, spatial…