The discrepancy between middle-class and lower-class children's performance on IQ tests has been thought of as "cognitive deficit" or as "cognitive differences." This paper proposes another explanation--cognitive lag hypothesis--according to which the low IQ test scores of lower-class children are seen as due to the developmentally delayed…

Several common assumptions about human intelligence are challenged in this paper. The "bucket" theory of intelligence describes intelligence as a stable psychological characteristic which affects learning, and which, when accurately measured, predicts an individual's learning capacity. The authors reject the idea that people who have…