The research group also discovered that "timbres" — or the distinct "textures" produced by different instruments playing the same note — have gotten more homogenous over time. To be clear, this is not to say that musicians are using fewer or different instruments now than before; rather, since 1955, pop has tended to use a smaller and more homogenous palette of "tone colors" at a given time.
The final finding — that music recordings have grown louder and louder over time — will come as no surprise to those who've been following the so-called "Loudness Wars, " but this seems to represent the first data-driven proof of the phenomenon. As producers compete for the attention of radio listeners to make their artist's recordings a hit, they've been gradually ratcheting up the inherent volume of the tracks at the cost of sound quality and dynamic richness. (You can hear what this sounds like on YouTube.)
So all this study's conclusions seem plausible, but does it really mean that our pop is dumber than before? To answer that, it's important to also ask what the researchers didn't study. For instance, though "Call Me Maybe" is made from a rather blunt and familiar set of four chords, the infectiousness of the song, at least for this listener, is located in both the playful rhythmic friction between the vocals and instruments — rhythm, crucially, was not taken into account in this study — as well as the cappuccino-cozy, almost country quality of Jepsen's voice. (Note how it glides and sometimes endearingly stumbles over her love-drunk lyrics.)
Indeed, so much musical interest in this hip-pop and dance-pop moment of recent years derives from the pervasive four-on-the-floor dance beat — and, crucially, well-crafted rhythmic dissensions from it. ("Unchained Melody," while a gorgeous song, isn't known for its beat.) As tempting as it may be to try to decode the "musical discourse," as these researchers called it, there are certain aspects of music — ineffable and otherwise — that will always elude your dataset.