Weighted association map
I sketched out (in my pro gradu study, Urkuimprovisaation aspekteja - improvisaatio ja koulutuksen tukiaineet, Sibelius-Academy. Helsinki 1992) a representation which I call "weighted association map". This kind of representation could be useful in teaching and learning (for example in the beginning of a course). Instead of using only tables of contents, weighted association map could help students to get immediate view of all the main subjects in a certain topic, their significance and associations or perhaps correlations between them. It is a way of representation, which can be based on intuitive selections or perhaps some statistical methods (for example mds + corr. table).
Rounded shape is not necessarily needed. Perhaps tree like or arbitrary structure serves as well. I think it might be possible to use mds and/or correlation tables as a background methods for creating weighted association map. If arrowhead lines showing effect directions are needed, perhaps one narrowing line between two subjects is better. Thicker head indicates strenght of that direction. Subject titles can be "weigted" too using bigger symbols or alike.