The mutual interactions via electron exchange of redox couples in glass-forming melts were investigated from both theoretical and experimental points of view. A thermodynamic approach for considering the mutual interactions leads to the conclusion that the degree of mutual interactin in the melt should be proportional in part to the difference in relative reduction potentials EM' of the interacting redox couples. Experimental studies verify this conclusion for numerous redox couples in several composition/temperature/oxygen fugacity regimes. Geochemical systems simultaneously possess many potentially multivalent elements; the stabilized redox states in the resulting magmas can be explained in part by mutual interactions and by redox buffering through the central Fe(III)--Fe(II) couple in the melts. ¿ American Geophysical Union 1987