Hip Hop hailed as music pinnacle
For some it was the unforgettable tunes of the Beatles; for others the intricate "prog rock" arrangements of Yes or the thunderous melding of blues and folk that was Led Zeppelin.
But no - according to a new scientific study the pinnacle of popular music evolution was the emergence of Hip Hop.
And while 1991, when rap rose up from the streets and went mainstream, marked the biggest revolution in chart culture, 1986 was the year it progressed the least.
The research, led by teams from Queen Mary, University of London (QMUL) and Imperial College, found that chart diversity was in the doldrums in the mid-1980s - chiefly due to the spread of drum machines, synths and samplers.
However the scientists also rejected claims that pop music was becoming increasingly homogenised and creatively stifled today.
Assisted by the music website Last.fm, the researchers analysed 30 second-long segments of around 17,000 songs that appeared in the US Billboard Hot 100 chart between 1960 and 2010.
Computer software was used to group the songs according to their musical properties, incorporating the kinds of instruments used, chord patterns, tonal character, and genre.
The study identified three key music "revolutions" - in 1964 when the Beatles and Rolling Stones led the "British invasion" of America, 1983 (marked by the "new wave" blend of synth-based pop and post-punk rock) and 1991.
Of the three, Hip Hop's big entrance into the charts in 1991 was said to be the most far reaching. Perhaps strangely, punk rock itself was not rated as a major force for change.
Lead author Dr Matthias Mauch, from the School of Electronic Engineering and Computer Science at QMUL, said: "For the first time we can measure musical properties in recordings on a large scale. We can actually go beyond what music experts tell us, or what we know ourselves about them, by looking directly into the songs, measuring their make-up, and understanding how they have changed.
"No doubt some will disagree with our scientific approach and think it's too limited for such an emotional subject but I think we can add to the wonder of music by learning more about it. We want to analyse more music from more periods in more countries and build a comprehensive picture of how music evolves."
Rather than changing the landscape of popular music, the "British invasion" merely followed existing trends, said the researchers.
The impact of Hip Hop, the rhythmic rapping style that originated in Jamaica and became the voice of disaffected black youth in New York and Los Angeles, was much more profound, they claimed.
The scientists wrote: "The rise of rap and related genres appears .. to be the single most important event that has shaped the musical structure of the American charts in the period we studied."
They pointed out that the history of popular music had "long been debated by philosophers, sociologists, journalists, bloggers and pop stars".
But their accounts "though rich in vivid musical lore and aesthetic judgments" lacked what scientists sought - "rigorous tests of clear hypotheses based on quantitative data and statistics".
Though limited to the US, the findings formed "the basis for the scientific study of musical change".
The scientists said: "Those who wish to make claims about how and when popular music changed can no longer appeal to anecdote, connoisseurship and theory unadorned by data."