Even unapologetic Top 40 hit-lovers would have a hard time denying the claim that popular music, on the whole, tends to sound pretty repetitive. This assertion feels so intuitive, that even detailed scientific studies backing it up tend to be met with a shrug. While hardly indicative of Good Art, repetition and simplicity aren't all bad. In fact, most listeners tend to seek a balance of familiar and new, two factors that "influence not only how we perceive popular music, but also how it is produced," according to researchers behind a new PLOS One study that examines how a style's musical complexity increases or decreases over time in relation to album sales.

Perhaps unsurprisingly, the Medical University of Vienna, Austria, scientists found that the more popular a musical style grew, the more generic it became—partly due to the glut of artists that flock to a burgeoning sound and the drop-off in innovation that tends to accompany demand.

The study looked at the "instrumentational complexity" of more than half-a-million albums from 1955 to 2011, across 15 genres and 374 styles as diverse as "hyphy," "viking metal," "acid jazz," and "Korean court music." Within those styles, researchers analyzed the use of nearly 500 instruments. Styles that used generic instruments found in many other styles had low complexity, while styles with a wider array of instruments that were used in fewer styles had high complexity.