Yes, it's highly heritable, and yes, it's also quite complex.
Besides, looking at an
individual and trying to gauge relative levels of cognitive ability via
performance proxies is really just a guessing game unless you
know that you're seeing glimpses of what that person is truly capable of, and that they have no other disability/challenge which is preventing that kind of performance.
Without all of the adaptive tech, Stephen Hawking wouldn't still be able to wow people with his insights, YK?
That's an extreme example, but just because you didn't finish an undergraduate education, that doesn't make you less intelligent.
My father was
definitely PG-- certified by the Navy repeatedly, in fact-- but his path was a non-academic one, by and large.
My family and my DH's, our paternal genetics is where our cognitive outlier status comes from. DD seems (from a functional stance) probably PG, and family who have known them both well compare her to my father. In my DH's family, there is no comparable person. My family produces the occasional PG person (seems to be about 1 of 20 or so), among a backdrop of a majority of people who are MG, and a regular sprinkling of those at higher LOG. I'm at least EG, depending upon which instrument one considers. I'm not in my dad's league-- using the same instrument, his IQ was over 10pt higher than mine (SB-LM). On the other hand, mine is ten points higher than my DH's.
Functionally, there isn't a TON to separate my DH and myself in day to day life. I'm a little quicker than he is at strategic thinking, but he's faster than I am computationally.
My mom and my DH's mother were both 'bright' at most. But both had siblings who were clearly gifted of one variety or another.
We expected DD to be gifted. Maybe even HG. But I'm not sure that any parent is truly prepared to deal with a child who turns out to be PG. There
is no preparing for it because that kind of extreme asynchrony turns out to be a developmental arc like a fingerprint-- almost unique due to the shaping forces and number of influences swirling together. Those things, in turn, push the individual into outlier range in various dimensions of human experience, and ultimately produce an adult individual who is
still an outlier because of a lack of peers with shared experiences.
My dad found me enchanting intellectually-- my cognitive abilities delighted him. We have found our DD to be a similar delight. There is no need to over-simplify concepts or conversation with such children. A lifetime of that kind of intense relationship is an
amazing bond to share with your child.
