The pace of modern culture.

Here we investigate the evolutionary dynamics of several kinds of modern cultural artefacts-pop music, novels, the clinical literature and cars-as well as a collection of organic populations. In contrast to the general belief that modern culture evolves very quickly, we show that rates of modern cultural evolution are comparable to those of many animal populations. Using time-series methods, we show that much of modern culture is shaped by either stabilizing or directional forces or both and that these forces partly regulate the rates at which different traits evolve.