It's biological.
According to Robert Sapolsky, a primatologist, MacArthur genius, and all-around wit at Stanford, from the years of eighteen to twenty-four, individuals in our species are curious, eager to try new things (such as music)...but by the time we are forty, more than ninety percent of us know what we like and are uninterested in anything new, be it music, food, or body piercing.
A wonderful story on NPR explains why Sapolsky became interested in this question, and how he researched it.
Here's the nickel version: a few years ago, Sapolsky noticed that his office assistant, a student named Paul, was driving him a little crazy. Not because of his work, which was excellent, but because of the absurdly wide range of music he listened to at his desk.
On Monday, it would be Sonic Youth. On Tuesday, Bavarian polkas. On Wednesday, pgymy love songs. On Thursday, Puccini operas. And so on. Sapolsky liked music too--Bob Marley, basically. But even though he once listened to more than Bob Marley, now hearing every possible kind of music was driving him nuts. He set out to find out if his experience was unusual.
Sapolsky called up fifty radio stations, talked to the station manager, and asked the same two questions: What is the average age of the listener, and the average date of the song release that they liked?
It turned out that the linkage between age and taste is so well-known in the radio business that they have a phrase for it: "Breakthrough minus twenty."
Take the decade in which the artist broke through (say, Billy Joel in the l970's) and subtract twenty years, and the listeners who like Joel will almost certainly have been born twenty years before.
Or, as Homer Simpson put it: "Music achieved perfection in l974."
Sapolsky had Paul call sushi restaurants in the Midwest and found something very similar. A vanishingly small number of people will try sushi after the age of thirty-nine if they haven't tried it before, and they're far more likely to like it if they tried it during those experimental years of 18-24.
He asked about body piercing too: Same thing. One tattoo artist told him: "If you don't have tongue studs by twenty-two, there's a ninety-five percent chance you won't."
Why?
"There's something much more deeply biological than just psychological about this," Sapolsky said, alluding to lab studies that showed a similar bias towards experimentation in other species. "I think once you get older, solid footing becomes real comforting," said Sapolsky.
Two business professors, Robert Schindler and Morris Holbrook, found a similarly deep-seated explanation for nostalgia. As Steven Zeitchik said of their work last year in the Wall St. Journal, "we all have a particular period when we think that the culture was at its most enjoyable--and it's almost never the present."
This has important implications, because there is good evidence that our political preferences are formed as firmly as our musical tastes--and at about the same time. Here's a graph from the NYTimes (based on a huge study by the Pew Research Center for the People and the Press) that makes a complex point about as clearly as possible.
To put it in a nutshell: If you're a Republican, chances are you came of age during the Reagan or Bush I admnistrations, when Republicans were riding high. If you're a Democrat, chances are you came of age during the Nixon or Ford administrations, when Republicans were in the toilet.
The potential good news? Young people--age twenty to twenty-four--are more likely to be Democratic and less likely to be Republican than ever before. The Currant Occupant of the White House is souring an entire generation of Americans on Republicanism.
