Narcissism: On the Rise?

We all know the myth of Narcissus, the young man, who like many of our teenage selves, spent too much time staring back at himself in a pond, a mirror in our cases, and essentially fell in love with himself.  Recently, I came across an interview with Dr. Nathan DeWall, a psych professor at Kentucky U, in which he describes his recent study that concludes that the increase in egotistical song lyrics over time directly correlates with a huge increase in narcissism in society.

DeWall's study analyzed the lyrics in songs on the Billboard Hot 100 Chart from 1980 to 2007 and found a statistically significant trend toward narcissism in lyrics, with the words "I" and "me" gradually replacing "we" and "us."  So, nowadays, instead of talking about love being between "we" and "us," it's more about, as Justin Timberlake put it so well...

When asked the question:

"So how does this affect the way teens and young adults and even old folks who listen to this music function in society and think about themselves as they sing along to all this?"

DeWall answered:

"It reinforces this idea in American culture that we really need to focus on how people feel about themselves. You know, we can't really threaten other people's self-esteem. We can't give them accurate feedback about who they really are. People who are very narcissistic, they come off as very confident, but if you insult them or provoke them in any way, it sort of breaks their bubble, and they're very fragile people."

So are the increasingly narcissistic lyrics in popular music a reflection of the growth of narcissism in our society, or are the opinions expressed in pop music making us more obsessed with ourselves?