"Many people enjoy sad music, and that's a bit of a paradox - why would we want to make ourselves sad?" he asked. "The same can be said of music with aggressive or violent themes. For us, it's a psychological paradox - so [as scientists] we're curious, and at the same time we recognise that violence in the media is a socially significant issue."
With a classic psychological experiment that probes people's subconscious responses; and by recruiting death metal fans to take part. The test involved asking 32 fans and 48 non-fans listen to death metal or to pop, whilst looking at some pretty unpleasant images.
Each participant was played Happy or Eaten through headphones, while they were shown a pair of images - one to each eye. One image showed a violent scene, such as someone being attacked in a street. The other showed something innocuous - a group of people walking down that same street, for example.