I found myself, oddly, wondering about earrings. What is the source point for why we do this particular thing to ourselves? Is it something so deep seated that we won't be able to suss it out? Myself, I would argue that it's something profoundly hard wired. We have been putting things on, around, and through ourselves, for as long as we have been upright hominids, and probably before that.
But what I'm getting to here is that we consistently, and across all cultural boundaries, do this thing. What culture, anywhere, does not indulge in the practice of hanging metal, stone, wood, glass, or anything else from the earlobes? To me, that would argue that this is something larger, and older than any individual society could claim. We seem to have brought this from our prehistory. And we do it still daily, all over the globe. In fact, we do it more often, and with greater variety than ever before.