Supersmarts: How high can IQs go?


Q. How high can IQs get? We know from the Flynn effect that IQ test performances have been improving worldwide by about 3-5 points per decade. So kids are smarter than their Moms and Dads, and so on. Where will all this take us in 100 years or 1000? –S. Hawking

A. There are really two important influences on IQ scores, says neurobiologist William Calvin, author of A Brief History of the Mind: (1) How many concepts can you mentally juggle at the same time? Multiple-choice questions usually require about six, and some people can do nine or ten. The right kind of training in youth might double that. (2) How long does it take you to understand the question, reach a good decision, and move on?

IQ is more complicated than just those two, but conceivably IQ scores might be doubled without genetic changes between generations. Obviously, only some jobs demand high IQ: Good doctors certainly need it, but most high-end work such as doing science doesn't often require thinking speed.

"Most of us can 'sleep' on a problem in a way that physicians cannot," Calvin says. True, there's no theoretical limit on IQ performances, adds Yale's Robert Sternberg, but these tests just assess memory and analytical skills, not creativity or practicality.

"What the world lacks is not IQ but wisdom," he says.

Q. What's the long and the short of the human height life story? –M. Hingeley

A. Barely 0.14 mm "tall" (zygote diameter) at the get-go, we grow 5000 times that by the 38th-40th week inside Mom, finally to 20 in. by birth, say V. Gregory Payne and Larry D. Isaacs in Human Motor Development: A Lifespan Approach. By Birthday #1 we reach 30 in., then another 4.75 in. the second year; afterward a general slowdown until that dramatic growth surge of adolescence beginning around the 10th-11th birthdays for girls, 12th-13th for boys, and lasting 3 years or so.

Since girls get started earlier, they are often about 1 in. taller than boys from ages 11-13. Most adolescent height gain comes from a lengthening of the trunk, not the legs, which spurt earlier.

"Thus"– as one expert put it– "a boy stops growing out of his trousers (at least in length) a year before he stops growing out of his jackets."

By the time a young woman hits age 16.5 years old or a young man 18, they're at 98 percent of their adult stature, 3.5 times what they were as newborns, say Payne and Isaacs. The story is almost over, except for a last ignoble chapter for some of us, when later disk degeneration or even spinal curvature steals away a bit of our altitudinous younger selves.

Q. I've wondered about this since high school. If I were to drop a "superball" type hi-bounce ball from the 1250-feet height of the Empire State Building, what would happen? Would it bounce super high? Shatter? I can't try this, but I'd love to know. –M. Jordan

A. You can save yourself, oh, about 100 floors ascent because the small lightweight ball would rapidly come into balance between gravity accelerating it downward and air friction retarding its fall, says University of Washington professor of mechanical engineering Colin H. Daly. In other words, the ball would reach terminal velocity, maxxing out at maybe 30-40 mph for the rest of the way down. So you could just as well drop it from the window of your apartment 5 or 6 stories up and get the same bounceback, about 30-50 feet.

"It would likely survive this without shattering," Daly says.

For a truly smashing experiment, build a skyscraper in a vacuum somewhere. Now drop the ball from just 1000 feet up and without air resistance it will accelerate to 172 mph. Get ready to go pick up the pieces!

Send Strange questions to brothers Bill and Rich at