More specifically, consider a 25 year old resident of NYC in 1964 - a member of the jet age, the atomic age, and the transistor era, embedded in a time of great cultural change in American life - and bring them to NYC of the present.

How long do you think it would take for them to get up to speed? What are the "significant life-changing technologies" they would need to learn in order to survive and do well?

Consider then a 25 year old resident of NYC in 1875 and bring them to 1925. I think it would be much harder for that person to adapt than the person from 1964.

Here are some of the significant changes around the turn of the century.

The linotype machine completely transformed the news industry. Before then, no newspaper had more than 8 pages.

Oceanic telegraph lines were in place, so the explosion of Krakatoa became world-wide news within a day. That is, the speed of information was already pretty high. There were 14 million telegraphs daily by the early 1900s, or 1 for every 100 people.

Books and magazines provided a lot of information quickly about the latest inventions and ideas. Take a look at Popular Mechanics from 1905, at http://books.google.se/books?id=S98DAAAAMBAJ&pg=PA93&hl=sv&s... for the news. Page 35 has a series of books for home-based education, from stair building to telephones to law school.

For the first time in the US we had more Americans living in cities than on farms. The end of the frontier era lead to Turner's Thesis, which is the basis for the "Frontier" in "Electronic Frontier Foundation."

Dense cities became possible because Otis elevator (1853) and iron-framed building (1864) lead to the first skyscraper, at an amazing height of 10 stories (1884–1885). Commercial use of reinforced concrete also started at around that time.

We developed new methods of information organization, including the Dewey Decimal Classification (okay, that's from the late 1870s), and the vertical file system. The Hollerith punch cards were invented for the 1890 census.

For the first time we had night life, because limelight and electric lights were much cheaper than candles. The first night club was Webster Hall in 1886.

For the first time, humans could fly against the wind, in both airships and airplanes.

For the first time, women could vote.

The steam shovel was invented in 1839 but it wasn't until after steel cable of the 1870s that lead to the first effective shovels of the 1880s. Compare the use of forced labor for the Suez canal to the Marion steam shovel used the Panama Canal a few decades later.

Speaking of the Panama Canal, we discovered that mosquitoes were a disease vector for malaria and yellow fever. Previously it was attributed to "bad air" or an impure lifestyle.

In my own field of chemical information, Beilstein's Handbook of Organic Chemistry started in 1881 and IUPAC nomenclature started in 1892.

Bakelite (1907) was "the material of 1000 uses" and it was used everywhere.

It wasn't until 1912 or so that lipstick became fashionable, and for the flappers of the 1920s it was a sign of independence.

It used to be safe to walk on the streets without worrying much, because most traffic were people, horses, and bikes (the 1890s was the 'Golden Age of Bicycles'). Cars changed that. The concept that streets are only for cars, and that walking across the street is "jaywalking" and wrong or illegal, started in the 1910s.

Do you really think the last 50 years are as disruptive as that fin de siècle era? Why?