Genius does not appear in isolation;rather, one genius cluster with others of greater or lesser fame in adjacent generations. These cluster A.L.Kroeber called Configurations. When a configuration reaches a crest, a Golden Age of creative activity is the result; when the configuration descends to a trough, a Dark Age occurs.
If genetics cannot explain the leapfrogging of Golden and Dark Ages, what can? He argued that geniuses cluster in history because the key figures of one generation emulate those in the immediately preceding generations.