Though separated by about a thousand years, both were quasi-urbanized societies which developed independently, built large stone structures and display evidence of early hierarchical systems, yet didn't develop writing or much in the way of artistic tradition. However, the way they're written about seems very different. Why, exactly? Is it just a bias against or disinterest in West African culture, or am I overlooking characteristics that set them apart?
Edit: I phrased the title in a slightly awkward way; obviously "cradle of civilization" refers to the place, not the culture. But you know what I mean. One is regarded as a fully-fledged civilization and the other isn't.
You may be interested in this thread from /u/qhapaqocha and myself which cautions against reading too much into popular usage of phrases like "cradle of civilization," particularly regarding the site of Caral. Caral has had the privilege of an archaeologist adamantly defending it as the singular center of all later Andean societies and a Peruvian government co-opting it in nationalist "the origin of Peru!" tourism campaigns. It's a really cool, really old site, but a lot of people involved have used the outdated language of "civilizations" for modern political goals.