Several studies have reported that older black and Latino adults have lower cognitive function test scores than older white adults, but few have comprehensively examined reasons for score differences. This study evaluates whether differences in health and socioeconomic indicators, including literacy level, can explain differences in cognitive function test scores between older black and white adults.  Murray was wrong in 1994 in his reading of the evidence for a genetic basis for the black-white IQ difference — and that he is wrong today. We argued that it was misleading, even irresponsible, for Harris to treat Murray as if he were someone who merely passes along scientific facts — facts so sound that they can only be doubted by liberals in the grip of “a politically correct moral panic,” in Harris’s words. All three of us are academic psychologists who have studied human intelligence, and it is our contention that Murray’s views do not represent the consensus in our field.

We start by noting that we accepted as facts many claims that are controversial in the academy, if not in psychology — that IQ exists; that it predicts many life outcomes; that there is a gap between black IQ scores and white IQ scores; that IQ is at least partly heritable (as is almost every human trait). We rejected the conclusion that Murray and Harris say is virtually inescapable: that it follows that the black-white difference in IQ must be partly genetic. 

Given the response to our first article, we thought it would be useful to clarify the precise boundaries of the dispute, as well as respond to some technical points critics raised. The central issue at stake is whether the black-white IQ gap is partially genetically determined. We believe there is currently no strong evidence to support this conclusion, whereas Murray presents it as a near certainty, and Harris endorses Murray’s position.

To be fair to our critics, it can be a little hard at first to pin down Harris and Murray’s position on this point. They both offer broad caveats, like this one, from Harris: