Nutrition and starvation absolutely is a massive factor in IQ. That alone is all you need to explain East/West Germany. I have no idea why 'paranoia' would affect IQ, and am not sure about 'violence' (I suppose head trauma would likely negatively affect IQ though.)

Nutrition and starvation absolutely is a massive factor in IQ. That alone is all you need to explain East/West Germany. I have no idea why 'paranoia' would affect IQ, and am not sure about 'violence' (I suppose head trauma would likely negatively affect IQ though.)

Starvation is not an issue in the western world. And even when you match for SES/dual vs single parent homes in America, there is still a 8 point IQ difference amongst races (Which obviously minimizes the actual difference, because IQ contributes to ones eventual SES). (page 25 here. There is simply no plausible explanation for this other than genetics, unless you believe in magical systemic racism horribly affecting even middle and upper class black people.