Original observation ... thanks to George, my favorite fifth grader. Consider the answer you might receive asking a grade-school child the question "What is 2 plus 2?" in each of the last five decades: in 1956 "4, of course" in 1966 "3, but it's the method that's important" in 1976 "just a second while I get out my calculator" in 1986 "just a second while I launch 'Calculator' on my Mac" in 1996 "just a second while I check the addition home page"
(From the "Rest" of RHF)