Notes to pull heart-strings

Aisling Irwin and Juliet Vickery report from the British Association for the Advancement of Science in Birmingham

The indefinable artistry that makes one musician's performance more moving than another's has been tracked on a computer.

Scientists have compared the rendition of a piece of music by ten different pianists and matched the performances note by note with the emotional responses of listeners. They have traced the power of one piece of music to a single note played differently by one of the ten.

The discovery is the latest in a series of findings about the effect music has on our emotions. Johnathan Sloboda, professor of psychology at Keele University, used the latest MIDI (musical digital interface) technology to record and analyse the pianists as they performed Chopin's Prelude in E Minor.

He played the recordings to listeners who had learned to use a system for measuring the degree to which people are moved by music. They used a joystick and moved it left or right according to what the music was doing for them. When asked about the performances, most people said they found one particular pianist more uplifting than the others.

Then Professor Sloboda discovered that their joysticks whizzed to an emotional high at one particular note played by that pianist. This pianist played the note more quietly than the others. Professor Sloboda said: "Emotions are responses to change. They seem to be a biological signalling system to alert the organism to change. Music, because it unfolds over time and has very strong patterning, creates expectations in us. When these expectations are not fulfilled, it creates a tension. You want it to be resolved. Strong emotions in or out of music are triggered by confirmations or violations of expectancy."

His earlier work showed, for example, that the appogiatura, a musical device, causes a surge of emotion in many people. An appogiatura is an ornament to a note: before playing the note, the pianist sounds the note above it, resulting in an initial clash with the harmony which is then resolved.

An example is the Beatles song "Yesterday", in which the first note, "Yes-" is a step above the second, melody note. "Yesterday" provokes crying and shivers down the spine.

Professor Sloboda said that the Chopin prelude has a very simple structure alternating between two notes. "The emotional device is fairly early on," he said. "Suddenly one performer drops the volume of that right-hand melody at a place where one would not expect it. It is not in the score."

Professor Sloboda's news will not be welcomed by everyone. "There is an intellectual battle going on about the degree to which you can apply quantitative rigorous method to the analysis of music," he said. He claimed that scientists are hundreds of years away from a music "cookbook".