Lyrics: Not as violent/profane/"offensive" as they used to be?

There's an assumption that the number and intensity of references to sex and violence and otherwise "offensive" content has a certain upward trajectory across the years: each generation of parents complains about how media content is somehow worse than it was when they were young: more anti-social, dumber, or more harmful in some way. If you look at ALL media experiences, this trend seems to be holding. Yesterday, parents worried about rock and roll music and comic books, today they worry about video games and Facebook. Mind you, I don't think that this cycle of worry has anything to do with the actual effects of these media experiences: most of the people on either side of these moral panics aren't very interested in empirically testing their claims. Nevertheless, content analyses of media experiences would, I think, show a kind of evolution over time, with some taboo activity (typically related to sex or violence) getting more numerous, intense, and realistic as time goes on.

But if you look WITHIN a certain medium, like popular music, I'm not sure the trend holds. Have the lyrics of songs gotten "worse" - more references to sex, drugs, violence, other taboo subjects - over the past 20 years? Two things make me think they have not obeyed this upward trajectory.

1: personal experience. I admit, I'm an old fogey. I'm 36, I mostly listen to music that was written last century (and occasionally before that), but I listen to pop radio on a semi-regular basis and absorb aspects of most cultural trends in the way that any user of meme-based entertainment websites does. I can still detect the shifts in popular genres of music (the ascendance of EDM for example). Of course, there are small sub-genres I'm completely unaware of, but that was always the case: there were always musical niches listened to by the minority of listeners, and often those were the places where future popular music would arise from. But I'm willing to bet that even if you sampled music from every genre you could find, even the small ones, the lyrics would not be any "worse" than they were in the 1990's. So I guess I'm making two claims: the "worst of the worst" in lyrics today is no worse than it was in the 90's, AND the average popular song is no "worse" in lyrics today than it was at that point. The extent to which lyrics of popular music were anti-social and taboo-violating peaked in the 90's (but maybe I'm just saying this because it was the time when I came of age, when I was rebelling, seeking out the "worst" lyrics I could find).

2. Crime rates in the United States. I recall that many people - pundits, scholars, and everybody else - looked at the trend in violent crimes in the US during the 20th century and assumed that the upward trend would just continue. But it didn't. Murder rates, burglary, you-name-it have all fallen since the 90's. There are many reasons for this, I'm sure, but it made me think about lyrics and certain assumptions about lyrics simply because it was another case of people being mistaken about a trend continuing unabated. I'm not saying these two trends (assuming the lyrical trend is real), which would be more-or-less simultaneous, are causally related (though if I had to speculate, I would say that the lyrics reflect social reality and not the other way around, or its a reciprocal relationship). It just got me thinking that trends are often part of cycles, not inexorable laws with one trajectory.

Of course this is just a hunch. I'm looking for a quick way to do a little content analysis to test this hunch. There are a lot of useful databases out there now, so I assume it could be done.

To return to my point about lyrics and their place in the media environment: I get the sense that teen rebellion (or just rebellion in general) is no longer the domain of popular music. Lyrics went about as far as they could go in terms of violating taboos. The internet clearly allows for more rebellion, more anti-social behavior (not only in word, but in deed), which, I suppose, underscores the importance of taking a holistic view of media use, whether you're a parent, a scholar, or both.