It's a reasonable hypothesis, I'm just doubtful that the poll, worded as it is, counts as evidence of this. Another hypothesis is that people know more about t

It's a reasonable hypothesis, I'm just doubtful that the poll, worded as it is, counts as evidence of this. Another hypothesis is that people know more about their parents and grand-parents than they do about their more distant ancestors, and that people are more likely to answer polls that are easy to answer than polls that are hard to answer. This hypothesis would also explain the results we're seeing in the poll.