Steve Sailer talks about a study from 1978 which shows that, after Warsaw was rebuilt in the aftermath of WW2 by the socialist government whose policy was to allocate housing, schools and hospitals without regard to social class, IQ was unrelated to neighborhood but strongly related to parental occupation and education. He seems to think it supports the hypothesis that neighborhood doesn’t have any effect on IQ, but I think it’s clearly the wrong conclusion. People who think that neighborhood affects IQ do so because, except when a socialist government engages in large-scale social engineering, people are not distributed randomly across neighborhoods. But if they are distributed randomly, then of course IQ is not associated with neighborhood. What this study suggests, it seems to me, is rather that differences in IQ can’t be explained just by environmental factors. But except for people who don’t know anything about the psychological literature on intelligence, such as most philosophers who talk about IQ, we already knew that, so I don’t think that this study has the significance that Sailer — who does know that literature — apparently thinks it has.