Motown Treasures

I’ve noticed that the backing vocals—especially on recordings by Martha Reeves and The Vandellas—were often arranged in a very lavish style; examples include "I’ll Follow You," "Remember Me," and "Wild One," a track where the producers themselves even stepped up to the microphone! Was this perhaps done to create a counterpoint to Martha Reeves’ powerful, gospel-infused voice—something akin to a church choir? Does anyone have any thoughts or confirmation on this?