Rika & J. Bartlett:

   "Do any members of this list know whether in fact
   any such investigations have already been done? Are
   there any books or studies we could read that speak
   to the psychological "truth" of traditional ballads?
   If any of you know of any such writings we would very
   much like to hear about them so we can incorporate
   them into our explorations."

Wow, your research is fascinating.

I would suggest the work of Claude Levi-Strauss, the French anthropologist,
from whom I first discovered how wonderful and mathematical the study of
kinship can be. His work has been translated into English by E. Leach
(There's a Fontana Modern Masters on Levi Strauss by Leach).

I doubt Levi-Strass and Leach actually deal with ballads as such. But Leach
will lead you to the functionalist school (rather than Levi-Strauss's
structuralist approach) as prominent in England.

Malinowski, Brown, and Ardener are other British anthropologists who may
have something to say about folk ballads and their incorporation of mythical
ideas about kinship.

There's also "Sing a song of England", where he discusses some English
ballads from the perspective of anthropology. I forget the author, alas!

Good luck in your research, and keep us posted.

Best,

JL
(Mr)
Buenos Aires, Argentina.