The Flynn effect is too short a timescale. I don't really disagree, mainly because the idea that our ancestors were mostly very unintelligent compared to today

The Flynn effect is too short a timescale. I don't really disagree, mainly because the idea that our ancestors were mostly very unintelligent compared to today's average seems absurd given their known accomplishments. However, I do wonder from time to time if that could be explained almost entirely by selection effects. The short timescale of the Flynn effect could possibly be attributed to the lack of reliable tests for g prior to the 20th century, for example...