This paper introduces an ecological approach to quantifying diversity in musical compositions. The approach considers notations with distinct pitches and duration as equivalents of species in ecosystems, measures within a composition as equivalents of ecosystems, and the sum of measures (i.e., the entire composition) as a landscape in which ecosystems are embedded. Structural diversity can be calculated at the level of measures (“alpha diversity”) and the entire composition (“gamma diversity”). An additional metric can be derived that quantifies the structural differentiation between measures in a composition (“beta diversity”). We demonstrate the suitability of the approach in music using specifically composed examples and real songs that vary in complexity. We discuss the potential of the approach with selected examples from a potentially ample spectrum of applications within musicology research. The method seems particularly suitability for hypothesis testing to objectively identify many of the intricate phenomena in music. Because the approach extracts information present in the compositions – it lets the songs tell their structure – it can complement more complex modeling approaches used by music scholars. Combined such approaches provide opportunities for interdisciplinary research. They can help to fill knowledge gaps, stimulate further research and increase our understanding of music.

1) Background: Bipolar or manic-depressive disorder is a malign mental disease that frequently faces social stigma. Educational and thinking models are needed to increase people’s awareness and understanding of the disorder. The arts have potential to achieve this goal. 2) Methods: This paper builds on the recent use of heavy metal music as a thinking and education model. It emphasizes the artistic component of heavy metal and its potential to characterize the symptomatology during the episodes of (hypo)mania and depression and the recurrence of these episodes. Heavy metal music has diversified into subgenres that become allegorical to both the symptoms of episodes and the recurrence of bipolar cycles. 3) Results: Examples of songs are given that mirror distinct facets of the disorder. 4) Conclusion: Although the links drawn between art (music) and science (psychiatry) are inherently subjective, such connections might be used to trigger a learning process, facilitate judgment and decision-making, and induce affective reactions and memory formation in the listener. The approach may facilitate collaborative efforts and serve healthcare professionals and educators as a communication tool to aid the public’s comprehension of the disease and an associated social paradox: On one hand, bipolar disorder incurs substantial costs to society. On the other hand, it benefits from the creative artistic and scientific endeavors of bipolar individuals from which cultural and political gains may ensue.