The very way our children learn from us -- and, thus, learn best from us -- has been shown to promote social bonding. More, such imitation seems to be central to the creation of larger groups, of the extended order we now live in, and thus to the expansion of our morals in the way Darwin himself explained. It turns out that this kind of imitation is necessary for people of different cultures to get along. Thus, artists who use ideas and concepts from other cultures are not "appropriating" (a term created by multiculturalists whose theories are atavistic in nature, wishing to keep us separate from each other just as much as do racial purists) those ideas and concepts. Rather, such artists are working to create bridges between cultures, to bring us all together. Thus, are we learning from each other.
This could suggest one way for literary Darwinists to discuss cross-cultural works. To what degree do they contribute to our imitating each other? To what degree could they thus contribute? The effects may in fact be quite subtle. Is the use of a form from another culture, such as the ghazal or the Noh play, an imitation of this sort?