Da gab es hier schon mal eine Untersuchung zur Veränderung der Themen und Inhalte von Songtexten (der alte Quell-Link ist tot).
Jetzt wurden vor allem Gefühle und Moral (hängt ja zusammen) in Songtexten untersucht.
Our findings reveal an increase in moral vices (e.g., Harm, Cheating, Subversion), and a decline in expressions of moral virtues (e.g., Care, Purity), alongside a rise in negative sentiment, anger, and disgust […]
Studies tracking lyrical evolution show a consistent decline in positive sentiment (e.g., joy, serenity) and a rise in negative sentiment (e.g., anger, fear, sadness) […]
there has been a notable increase since the 1980 s in lyrics that underscore self-focus and self-promotion, serving as a manifestation of the growing individualism prevalent in American society […]
The clearest temporal patterns among the Binding-related dimensions were observed for Subversion and Degradation, both of which showed an increase over time, particularly among male and mixed-gender artists. Purity showed some fluctuation, rising during the 1970 s before gradually declining, with slightly higher expression among female artists.