The first set of criteria that I think of are: 1. To record personal or social history (c.f., the cave paintings at Lascaux. 2. To celebrate, propagate or reinforce cultural tradition. 3. To challenge or expand cultural tradition. To expand on one from a slightly different perspective, Joseph Campbell suggested that the Lascaux art was used as a transformative mechanism for young hunters by the elders, similar to bar mitzvah or confirmation.