What makes a catchy song?

Apparently a group of British researchers at the University of London have analyzed the trend of catchy songs and have come up with a list of 4 things that a song needs to be catchy.



The list then to making a catchy song is...

1. Long & detailed musical phrases
2. Multi-pitch changes in song's hook
3. Male vocalists
4. Higher male voices making vocal effort

I am not quite sure though that using Nirvana's "Smells Like Teen Spirit" is a good example of "long & detailed musical phrases" because, lets be honest here, most people have no idea what the actual lyrics of that song are.

The part about male vocalists is arguable as well. What about Joan Jett's "I Love Rock & Roll" or even "Bad Reputation" from her as well? I would consider both of them to be catchy songs. Then there is stuff like "Hit Me One More Time" from Britney Spears and "I Think We're Alone Now" from Tiffany.

Personally I think the researchers just came up with a list of songs that they liked and worked on coming up with a list of common factors instead of doing public research with a test control group. I just can't help but wonder if it was done with a taxpayer grant like a lot of silly studies in the US are.