Content bias was the most reliable effect of the three in explaining the rise of negative lyrics. This is consistent with other findings in cultural evolution, in which negative information appears to be remembered and transmitted more than neutral or positive information. However, we also found that including unbiased transmission in our analytical models greatly reduced the appearance of success and prestige effects, and seemed to hold the most weight in explaining the patterns. ‘Unbiased transmission’ here can be thought of in a similar way to genetic drift, in which traits appear to drift to fixation through random fluctuations, and in the apparent absence of any selection pressure. This process has been found to explain the popularity of other cultural traits, from decorations in Neolithic pottery to contemporary baby names and dog breeds.