By Katherine Gombay
The piano keys are moving on their own, but this is ain’t no old honky-tonk player piano. The Yamaha Disklavier that sits in Daniel Levitin’s lab is a sophisticated piece of equipment with motors and sensors, connected to a computer, hooked up to the underside of each of the keys. Levitin, from the Dept. of Psychology and the Director of the Laboratory for Music Perception, Cognition, and Expertise has been using the Disklavier for a series of experiments designed to measure how musicians communicate emotion.
The idea for the research came to Levitin when he was attending a disappointing performance of one of his favourite pieces of music, a Mozart piano concerto. “I love the piece, he’s playing all the notes, but I found myself thinking, ‘why is it that some recordings and performances move us to tears of joy, and others to tears of boredom?’” Levitin remembered learning as an undergraduate that, because of the physics of the piano, all of the subtlety and expressive nuance of a performance could be reduced to just three factors: how long the pianist holds the notes, how loudly he or she plays them, and then there are the pedal positions. Levitin realised that, given this limited set of parameters, this was information that could be manipulated and measured.
So Levitin and his colleagues asked a concert pianist, Thomas Plaunt, the head of McGill’s Piano Department, to perform one of Chopin’s Nocturnes on the Disklavier. They then worked on the computer files to create a number of different versions of the performance. The timing, loudness and pedalling were manipulated to create a continuum of versions of the piece, ranging from 100-per-cent expressive (the original performance) to 0-per-cent expressive – a wooden, robotic version in which every note is played at exactly the same volume and for exactly the same length of time.
Research subjects listened to the various versions of the Nocturnes played back to them in random order, without any indication as to the degree of expressivity in the performance, and they were then asked to rate – on a scale of 1 to 10 – how expressive they found each version.
The results were surprising. Even non-musicians both recognized and preferred the more expressive versions of the music. “They might hear an 80 per cent followed by a 20 per cent followed by a 60 per cent expressive and they were consistently able to recognize and choose the more expressive version. This tells us that even very subtle differences in performance are readily identified – even by average listeners. I found that astonishing,” he said.
The study also discovered that variations in the timing of a performance have an even greater emotional impact than do variations in the loudness of playing.
“The skilled pianist has learned to communicate musical emotion primarily by making some notes longer and some shorter, some louder and some softer – just like we do in normal conversation,” Levitin said. ”It stands to reason that one might be more important than the other, but I was surprised when it turned out that timing is more effective than the loudness in making you feel something.
“One of the hopes of this kind of research is that it will help us to better understand the alchemy of what goes into a moving performance,” said Levitin. “It’s really a big step forward in capturing and quantifying why music is emotionally moving.”