[MRM]

I do have considerable experience with IQ testing. The issue with cultural references and basic knowledge are from old-style tests. For the last twenty years or so IQ tests have moved away from knowledge-based questions, especially cultural questions, because they introduced significant test bias in favor of people who were exposed to the wider world. That's why wealthier kids did better in standardized testing in the 50s and 60s. Current IQ testing focuses on things that measure spacial perception, memory, and anlaytical skills. These things measure IQ more accurately and apply equally across cultures and levels of education.

I think your point was that test bias would flunk Lincoln out of a modern IQ test because he's not familiar with our cultural references; not that he had sub-normal intelligence. If so, I agree but your point didn't come across well. Even so, the modern testing is supposed to come closer to eliminating test bias and giving an accurate evaluation of intelligence.