Alternate explanation for:

everyone I talked to about this who were on the higher end of the intelligence scale had clear memory of their parents responding "I don't know, let's find out" to their curiosity when they were a child, while everyone else I talked to had no such memory.

Highly intelligent people tend to have better memories. If less intelligent people don't recall something from childhood, that definitely doesn't rule out the possibility that it did happen to them and yet had no effect, because they may just have forgotten about it.