A few year’s ago I presented a programme for BBC Radio 4 where I learnt how to make music that has unresolved dissonance. For #AcousticsAdvent I decided to do a new version of a Christmas classic – see SoundCloud below. The effect kicks in half way through. Below I describe why researchers were doing this, and how.
Consonance is where sounds are heard that together are pleasing and appear to be final. Dissonance is the opposite, it is where sounds clash and are unpleasant together, creating tension. A large part of Western music is about creating tension through dissonance and resolving it through consonance. This is true whether that is a chord progression in Lady Gaga’s latest hit, a 12-bar blues or a Handel oratorio. This feeling of tension being resolved is something we enjoy.
One theory for why dissonance is jarring, is because sounds with such clashes are harder for the brain to process. We have a natural liking for consonance because it is easier for us to process what we hear. But a lot of peoples’ preference for consonance over dissonance is about what you’re used to listening to. If you’ve be brought up on a diet of free jazz, you’re likely to have a higher tolerance of dissonance than someone who just listens to mainstream pop.
To try and get an understanding of how much of the perception of dissonance is innate and how much is learnt, Thomas Fritz of the Max Planck Institute in Leipzig sort out people who had not been exposed to Western music . He travelled to Cameroon in Africa to study the Mafa people. He got members of the tribe listening to Western music and Mafa ritual sounds, both in their natural state, and when rendered to be have unresolved dissonance. This is how it was done.
You take the original sound (first track in Soundcloud playlist below). You then shift that up a tone. You can do this in any audio processing tool like Audacity. You also make another version that is shifted down a tritone. You then mix all the tracks together to make the version with dissonance.
Fritz found that on first listening to a variety of music styles, the Mafa showed a preference for consonance over dissonance. Indicating there is something innate about the preference. But more recent work by Josh McDermott with people from the Tsimane society in Bolivia found the opposite result ! Currently, we have two studies that contradict each other. We need a third experiment to resolve this.
 Fritz, T., Jentschke, S., Gosselin, N., Sammler, D., Peretz, I., Turner, R., Friederici, A.D. and Koelsch, S., 2009. Universal recognition of three basic emotions in music. Current biology, 19(7), pp.573-576.
 McDermott, J.H., Schultz, A.F., Undurraga, E.A. and Godoy, R.A., 2016. Indifference to dissonance in native Amazonians reveals cultural variation in music perception. Nature, 535(7613), p.547.