Hi Bill ...
I'm not sure what the name of a lot of guitar technique is called, but as a Jethro Tull fan I do a lot of picking within the various chords. I guess I'm like the Joker in "The Dark Knight Rises", i.e., I just do things. It certainly is a great way to add a bit of interesting detail to a song when trying to sing at the same time, and isn't much more difficult than singing and strumming at the same time. Jim Croce also used this technique a lot, as well as James Taylor, Harry Chapin, Cat Stevens, etc.
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