Not the person you're replying to, but is also trained myself to do it. I basically touched the area where the muscle is, tried to activate it ... time passes ... and some unconscious process figured it out. Now, as a responsible parent, I use my super power to troll my kids.

I too trained it when I was in primary school after seeing a class mate do it.

And like OP I eventually managed to control one ear (right) but not the other, even to this day 40 years later

I can twitch my left ear independently from my right. But not the right one independently. I'm sure it means something. Both at the same time is easy.

Same here, same ear

>> I can wiggle each ear very visibly (and both). I hardly ever do but as I remember most people can’t. So i always assumed it was a DNA thing.

After reading the article I think its a "use it or lose it" thing where the muscles and ability to control them atrophy in our modern environment. We have more competing sounds and external means to "turn up the volume" so we can hear a particular thing.

It could be both