"One really does want to try it from age seven, but I'm not sure how much of this stuff even I could have gotten at age seven. It'd be worth trying, though."

I fully intend to teach my children (when I eventually have them, that is) about cognitive biases and rationality from the time they are born. I think that we greatly underestimate what children are capable of understanding. (It is also possible that I am biased, since I was an unusual child and so I can't generalize my experience across all children - but even if that's true, there is at least a good chance it will work with MY children, so much the better for them.) In the future, our children might be taught concepts in their earliest books that we have not even discovered today.