First they reacted to music from the 90s and while they did okay on that test, they didn't score as well going a further 10 years back. Some of the kids knew some of the songs because it's the right of every parent to try and brains wash their kids with the awesome music from their generation!
Take a look at how many songs they recognised from the 80s
If you missed the 90s edition of this video you can see that here!