Perhaps "early testing" needs to be thought about in terms of milestones, rather than ages?
Here are some ideas - please post yours:
-test the minute you become aware that the child is conceling their intelligence.
-test when other people's eyes start bugging out.
-test when your child becomes a reader, and there is reason to suspect that they are gifted.
-test when there are behavior problem in the classroom, or at home.
-test when you need to start making plans for your child's educational path.
-test when you throw away the baby books in frustration because the "timing is all off."
Perhaps we can come up with a working list of "developmental" triggers for testing that aren't age based.
