http://www.miller-mccune.com/culture-society/song-lyrics-reflect-our-narcissistic-age-29644/

"The researchers found the use of first-person plural pronouns (we, us, our) declined over the years, while the use of first-person singular pronouns (I, me, mine) increased. Words reflecting anger or antisocial behavior (hate, kill, damn) became more prevalent over the 28-year period.

Conversely, terms depicting social interactions (talking, sharing) became less common, as did the use of words conveying positive emotions (love, nice, sweet). These findings mirror “recent evidence showing increases in U.S. loneliness and psychopathology over time,” the researchers write."