Taylor Swift in New York at Madison Square Garden in December 2009, a year in which she became very familiar with the top of the Billboard charts. Bryan Bedder/Getty Images hide caption toggle caption Bryan Bedder/Getty Images Opinion 13.7: Cosmos And Culture Sex, Love And Evolution: Making Hits On The 'Billboard' Charts December 1, 2011 New research in psychology suggests that our favorite popular songs contain more messages about sex and reproduction than do less-favored songs. Is our evolved psyche at work here? Commentator Barbara J. King considers the evidence.