FUCK THE POLICE
911 EVERY DAY
I don't know about radically, but both adequate nutrition and cognitive stimulation can affect attention and perception. The tests have undergone some important modifications over the past couple of decades or so, once it was shown that the originals were seriously culturally biased. If poor children have little to no intellectual stimulation, for various reasons, that certainly will influence their test performance. The time during development that that stimulation is withheld or provided will also have an important effect. One question that nobody brought up is whether or not the tests are well enough designed to adequately tap into intelligence factors for all social strata.
I used the word "radically" because the study said that children adopted from poor into upper middle class homes scored 12 (?) points better, which is a pretty significant change on most IQ tests.