DarwinTunes is a computer program developed by Dr Bob MacCallum, a bioinformatician at Imperial College London. In the first instance DarwinTunes does three things. It stores a lot of computer-generated songs on a server, presents the songs to the world via a web interface, and allows people to listen to and rate them.
So far this sounds rather like the online music services on offer today – but there is an important difference. Whereas the songs on Last.fm, Pandora, Spotify, etc are made by singers, songwriters and bands, DarwinTunes makes its own songs, and the songs get better through time.
DarwinTunes does this by evolving new songs. Each song in DarwinTunes is based on a bit of computer code. These bits of code periodically “reproduce” to form a new population of daughter songs. However, the daughters are not the same as their parents. First, parent songs have “sex” – they exchange bits of their code so that their daughters are unique mixtures of their parents’ codes. Second, daughters “mutate” – they contain random changes in their code. The result is that every generation of songs is subtly different from the one that preceded it.
These processes are analogous to those make genetic variety in living things; we think that that they are also at work when humans make new songs. They are not, however, enough for evolution. Many daughter songs will not sound very good; in fact, they may sound worse than their parents. (In the same way many mutant animals are very unhealthy.) In order to get evolution we need a way of identifying attractive songs – and ensuring that they increase in the population. In short, we need a selective force. And we have one: you.