A recent study published in the PLOS One journal examines how a particular style of music’s complexity increases or decreases over time with respect to album sales.

The study found that “album sales of a given style typically increase with decreasing instrumentational complexity,” which can be seen as “music becoming increasingly formulaic in terms of instrumentation once commercial or mainstream success sets in.”

The sample of music used for the study included more than 500,000 albums from 15 genres and 374 styles like jazz, rock and black metal. Using albums from 1955-2011, the study analyzed the use of nearly 500 instruments.

According to the Atlantic, “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.”

Why? Well, according to the study, we have a “tendency to popularize music styles with low variety and musicians with similar skills. Only a small number of styles in popular music manage to sustain a high level of instrumentational complexity over an extended period of time.”

As the Atlantic points out, genres like “euro house,” “disco,” and “pop rock” decreased in complexity but gained higher average album sales. On the flip slide, “alternative rock,” and “hip-hop” became more complex, and their overall album sales declined. The study said, “This can be interpreted as music becoming increasingly formulaic in terms of instrumentation under increasing sales numbers due to a tendency to popularize music styles with low variety and musicians with similar skills.”