What is the definition of "recently added" in my iTunes playlists? Are these songs that I have purposely added or could they be those songs added by iTunes because of my "genius" playlist....I need to know if these songs could have been added by someone other than me

What is the definition of "recently added" in my iTunes playlists? Are these songs that I have purposely added or could they be those songs added by iTunes because of my Genius playlist. I need to know if these songs could have been added by someone other than me.