  We present a simple population synthesis scheme which recognizes composite
starburst+Seyfert 2 nuclei from a few easy-to-obtain optical measurements.
Composite systems seem to evolve towards less luminous Seyfert 2's which do not
harbor detectable circum-nuclear starbursts. We encourage applications of this
cheap diagnostic tool to large samples of Seyfert 2's, as well as its extension
to other activity classes, in order to test and refine this evolutionary
scenario.
