Jan,
I disagree. I think -- while the distribution in the complexity with which most people deal with the world may be widening -- in general people today live in a no-more-complex world than people living 100 years ago. In many ways people live in a *simpler* world! For instance, think of cars: 40 years ago, the "average" person probably still knew how to change the oil and air filter, even tweak the carburetor a little between seasons or if they'd be driving over mountains. Today, the average person knows little to nothing of vehicle maintenance -- they just take it into the dealer every 7,500 miles, and things like carburetor adjustments no longer exist due to fuel injection with a computer controlling the oxygen intake. Similarly, 100 years ago, the average person knew how to hunt and farm, whereas today the average person only knows where the nearest 7-11, Starbucks, McDonalds, and a grocery store is.
Of course, the average person today knows many things people 100 years ago didn't -- how to write e-mail, how to play a DVD -- but my point is that the world is no more *complex* today for the *average* person, just... different.
What country did you say you're in? Here in the U.S. there's a TV show, "Are you smarter than a fifth grader?" where they routintely demonstrate that a lot of what's learned in grade school is lost in adulthood. School standards today in math and science are decidedly lower than what they were 40 years ago, and not just in primary education: An average EE today learns far less math than one who graduated in in '60s, and while they do know how to create web pages and program microcontrollers, the point again is that much of what they know is just different -- but not necessarily more complex -- than what would have been taught decades back.
The ability to learn does become slower as we age; that's an unfortunate fact. However, a significant decrease in many people is because they *don't* learn new things on a regular basis: It's no surprise that people who are used to learning all the time are better at it as they age than people who have, e.g., a manufacturing job where they do the same thing for 40 years. Just as many
60 year old men who've been working out most every day for their entire lives are in better shape than a 40-year-old couch potato.---Joel