Lots of great points so far. One thing that continues to puzzle me: what was Macaulay himself thinking of when he selected the word "adult"? (This may not be the same as what the word means to each of us.)
I had to chuckle with recognition when I read the following, from Kathleen O'Connell:
When I first started seeing NYCB regularly in the late 70s, the dancers did seem very adult -- but then they were all older than me, or at least my age. Now that they're all young enough to be my children and then some, they look like kids. It's that simple.
I know what you mean, Kathleen. I was in 10th grade when I first began attending NYCB regularly, so even Allegra Kent was unimaginably old, in experience if not in years.
I think, however, that there are other aspects of this. (Sorry if I go ahead an number them, but that's the way I think.)
(1) The dancers of the 50s and early 60s emerged from a very different system than those of later generations. There's was a risky business: no scholarships to speak of, impossibly low pay except at the top, a world in which becoming a "starving artist" was a real possibility, etc. They were
artists but they were also theater people. They were "on the stage," which had very different connotations in the old days than it does today. If that
didn't mature them, what could? Watching Hayden, Adams, Wilde, even Verdy: you knew that you were watching someone who had seen the world. They had mystery and a kind of inaccessibility. Suzanne Farrell, despite her baby face, never came across as young in the sense of naive and or sheltered.
(2) That generation of dancers, along with an older generation, became the teachers and coaches of the 70s and 80s, even after the School of American Ballet became a major institution and scholarships became widely available. Young dancers' behavior on and off stage reflected this, I think. They wouldn't have dreamed of making the kind of comments that young dancers today make routinely on video blogs for certain major U.S. companies. (I love kfw's term: "adolescentizing.")
How does this reflect itself in performance. I'm not sure. PeggyR's point about there being a difference between "dancing for the audience" and dancing for one's own sense of fun sounds pretty good to me. I notice, when reading and watching videos on the non-stop-chatter Miami City Ballet blog, that only one dancer -- Deanna Seay, the company's senior principal, who is retiring at the end of this season -- wished to talk extensively about the serious aspects of ballet as a performance art.