It just dawned on me today that the Beatles started a psychological phenomenon, playing records backwards to see if it says something cryptic. A lot of people, i've found out, still listen to songs backward, looking for hidden messages. I wonder if this phenomenon is in psychology books? It's not only Beatles music. It's spread to other music.

I agree. Now it is common for groups to do it. The one that stands out in my mind at first reading this was the song Another One Bites The Dist by Queen which says as plain as day - It is fun to smoke marijuana.  It is not garbled like a lot of the backwards stuff is. It sound just like you say it. I am not sure that I believe that all the backward masking is Satanic either.