The first half of the talk was by Lauren Stewart, a cognitive neuroscientist, who outlined how the brain understands music.
Music is entirely a construct of the mind, she pointed out, because sound waves are simply vibrating air molecules, nothing more. What is remarkable is not just that the brain understands how to interpret these sequences of molecules, but that we can also understand composites of several different strings of molecules interwoven together; i.e. the different musical elements – for example, guitarist, bass, drums, singer – that make up a song.
But how did the brain evolve this ability? One possibility is that music is a super stimulus for pleasure, said Dr Stewart. The brain, she said, is adapted to recognise patterns. The process of hearing a song and predicting what comes next sets off the neurotransmitter dopamine in areas of the brain associated with other pleasure stimuli, like sex and drugs – suddenly the old adage “sex, drugs and rock’n’roll” makes more sense! The “musical chills” that you experience when you hear a song you really like is a good example of this process in action.
Dr Stewart studies the disorder amusia, which is a lifelong failure to recognise familiar tunes or tell one tune from another. Sufferers frequently complain that music sounds like a “din” and often avoid social situations in which music plays a crucial role. Such individuals are unable to understand the up and down pitch of music, but have no problems with the pitch changes in speech, like rhythm, stress, and intonation.
Some people develop this problem after significant brain trauma, like a car accident, whereas others are born with it. Dr Stewart describes the genetic component of amusia, “congential amusia,” by highlighting a family of eight siblings from Northern Ireland, four of whom have amusia and four of whom hear music fine. In fact, a study of nine families with some amusic members and ten normal families found that 39% of first-degree relatives of amusic people have the same cognitive disorder, whereas only 3% have it in the control families.
By studying a “broken system,” Dr Stewart hopes to find out more about the “correct” cognitive architecture of music, and its relation to other cognitive skills such as language and spatial awareness. Her present research aims to elucidate exactly which perceptual and cognitive mechanisms are at fault in amusia, whether disordered musical processing has implications for language, and the extent to which such difficulties can impact upon sociocultural functioning.
The second half of the talk was by Daniel Müllensiefen, a computational scientist, who studies involuntary musical imagery, or “earworms.”
An earworm, a direct translation of the German word “ohrwurm,” is a portion of a song or other music that repeats compulsively within one’s mind – “I’ve got a song stuck in my head.” Earworms are related to voluntary musical imagery – earworm activate the same areas of the brain as when you’re listening to music.
Apparently, as many as 90% of people experience an earworm at least once a week, whereas about 50% have one everyday. The average length an earworm is on repear is 27 minutes, and between 15% and 33% of people find these “cognitively infectious musical agents” unpleasant or disturbing.
Dr Müllensiefen is using computational analysis of music to determine what it is about a song that makes it stick in our heads and become an earworm. He and his team have broken down the melodies over 14,000 pop songs from the 1950s to the present day into sequences of 0s and 1s that computers can deal with.
They have then analysed the statistical distributions and regularities in the data from commercially successful songs to determine what elements make a song a hit. Apparently, what you need is a chorus melody that has a large range and uses only few pitches much more frequently than the majority of its pitches. Which looks like this:
This talk was a great introduction to how the brain deals with music – both in instances where people can’t get a grip on music and in cases where they can’t get it to go away.
- If you’re interested in music cognition, why not head down to Dr Stewart’s and Müllensiefen’s event “Striking Your Own Chord: Journeys into Musical Plagiarism” on Wednesday 17th March at the Dana Centre, the Science Museum’s adult events spot.