Sorry, anecdotal and insignificant.

No, it is quite often "normal" for persons having memorization problems
(rote learning) to end up being at a much higher I.Q. AND be able to use it.
That problem is quite normal when they get older as well.  4th grade "math"
(arithmetic) is memorization and has NOTHING to do with IQ except possibly
in a reverse way.

They didn't have stupid, nonsensical, home environment, home work,
disruptions in his day.
"Unstimulating teacher"?    HA HA HA HA HA AH.  "Stimulation" was a whack on
the head, hand or butt.  It's called "Equal opportunity".
Learning was repetition.

Your input, local schools (government) have been influenced by the liberal,
Socialist junk from Europe.  In Germany, how one does in the fourth grade
says what type of school they are "allowed" to attend from thence forward.
The result is that the poor are kept poor, the rich can get temporary
tutoring.  All government leaders are given tutoring for their children.
That is where we are also headed, Socialism, controlling the populous to a
preset ideology.

Read some more on his childhood.

*****************************************
"With a few exceptions, his marks
ranged from good to excellent from primary school into
 university--and that included creditable work in fields far removed
 from those he truly cared for. "
***************************************************************
Absolutely true as far as it states, maybe even an understatement

Skipping one grade usually isn't a problem if the kid is of typical
maturity; there's always going to be a range of at least one year in any
grade due to the cutoff dates (e.g. a kid who was born on the cutoff date
is going to be a year younger than a kid in the same grade who was born
the day after the cutoff) so skipping one grade isn't going to have much
more effect than having a late-fall birthday.

Jan does have a point, though, about skipping multiple grades.  The fact
that a kid is *intellectually* able to handle college-level subjects at
the age of, say, 15 doesn't imply that he's *mature* enough to learn
those subjects in a college environment (where, for example, students are
expected to learn with little if any supervision; if you don't go to
class or do your homework, you just end up doing badly rather than having
teachers or parents getting on your case), let alone mature enough to
handle typical college life (again, the lack of supervision, for
example).  It's not merely a question of social skills (which lots of
people tend to poo-poo, arguing that it's no loss for the kid to miss out
on the typical high school clique system); it's really a question of
giving the kid a little time to acquire a bit of wisdom and for his
hormones to settle down a bit.

Another problem with going to college very early as a result of skipping
multiple grades is that the kid's options may be a bit limited when he
graduates.  If he's planning to go on to an academic graduate program or
work in certain "bleeding-edge" sectors of the technology industry he may
be OK, but if he wants to go into a professional (medical, law, business,
etc.) graduate program or into most private industry, his age is likely
to hurt his chances, again because professional schools and employers
want a certain level of maturity that isn't usually found in late-
teenagers.

Our son's life.  We helped him learn to pay attention and we would not allow
anyone to comment on his IQ.  We didn't either.  He was test by a
professional a couple of times.  Raising a child with a high IQ we were told
by his first psychologist is just as bad as raising a child with a mental
disease.  It wasn't easy but we got him involved in lots of activities.  We
also took him to places for fun that most don't get to do.  Someone can rate
high in their IQ but still be an idiot.  I don't deny that.  My husband
rates high in his IQ and had done well for himself and of course for us.  My
son can read and understand what he is reading, as a matter of fact, he and
his father can read something and years later tell you what page it was on
that they were talking about.  Everyone is different.  We didn't play the
game like you explain here.  My son has two degrees from college.  I am the
one who has trouble remember and keeping up with things.  I can read
something and then I forget most of what I read.  It's always been that way
for me though the older I get it's been getting a lot worse.  UM MOM Susan

That would be "cognitive". Do not claim it as a typo, as knowledge of the correct spelling
is cognate with your claim below to have studied psychology.

"Statistical Psychology"? Were you away the day they talked about how IQ is dependent on
age?