DJP's Spotify Time Capsule

More than half of my Time Capsule are songs that I've got on a playlist from the 1989-1991 era. By the time the fifth or sixth song from that rolled around, I thought, Well hell, I could just play that playlist if I wanted to.

Here's what DJP and I have in common:

Groove Is In The Heart - Deee-Lite
It Takes Two - Rob Base & DJ EZ Rock
Poison - Bell Biv DeVoe
Three Days - Jane's Addiction

I've got three Public Enemy songs to his two:
Countdown To Armageddon
Shut 'Em Down
Welcome To The Terrordome

Oldest song on mine is "You Dropped a Bomb On Me" by the Gap Band.

How does this thing work exactly? Does one have to have been using Spotify for some time I mean clearly it didnt exist in the 90s so whats it working this out from? I dont listen to anything like what I did in my 20s.

I'm not sure how the algorithm works but I think it infers from your birthdate and current listening habits, along with songs from that era that you currently play.