All right, I have completed my first listen-through of the most recent non-compilation album of non-Arashi J&A groups: A.B.C-Z, Hey! Say! JUMP, KAT-TUN, King & Prince, KinKi Kids, Kis-My-Ft2, NEWS, Sexy Zone, SixTONES (singles), SMAP, Snow Man (single), TOKIO, V6, Johnny's West, and Kanjani8. (If I missed anyone, please let me know!)

I did this with the program minimized and no pop-ups etc so I could try to listen to the songs without group-related preconceptions. What I found:

1. I probably recognized 95% of the TOKIO album because Nagase's voice is so distinctive.
2. The Eito album still had Subaru so if Subaru sang in an ear-catching manner, I knew it was Eito, lol.
3. Somehow I felt like I recognized a lot of SMAP despite never having heard this album. I've never listened much to SMAP, but I just kept thinking, oh, this is obviously SMAP. I also apparently recognize Kimura Takuya's voice really easily and I have no idea why!
4. I of course recognized the interludes of NEWS (having listened to a few of their previous albums and really liking Epcotia) but was surprised that I didn't really have any song-songs jump out to me as theirs.
5. I recognized one King & Prince song because I saw it performed on some music show.
6. I've listened to the SixTONES and Snow Man first singles so I knew it was them but I don't remember which is which.
7. There are a few songs where they say their group name in the song, so those ones got through. :D
8. I never had the feeling of recognizing or suspecting anything was from A.B.C-Z, HSJ, KAT-TUN (surprisingly?), KinKi Kids, Kis-My-Ft2, Sexy Zone, V6 (surprisingly?), or Johnny's West. This is a much lower rate than I was expecting, but it does make it extra fun, somehow!

Now stage two of this experiment can begin! I have added four more playlists to sort into. If I'm listening to a song and I don't mind listening to it but also don't feel a pull to listen to it specifically in the future, it stays in the first playlist. Then there are two playlist above neutral (for actively liking to some extent and really really liking a lot) and two below neutral (for a passive sort of dislike where I'd rather not hear it again but didn't feel the need to completely skip it, and then for an active dislike where I wanted it out of my ears immediately). I expect all five playlists to be populated. :D I will also remove the interludes, instrumentals, etc.

In stage two I won't avoid group names, though I'm going to keep pop-ups etc off so I only see them if I seek them out.

I've been looking forward to finishing stage one so I could see who the songs are by and sort them for future listening, yay! GO.