When a performance of his favourite Mozart concerto failed to hit the spot, McGill psychology Professor Daniel Levitin decided to find out why.
“I love the piece,” Levitin said. “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’s most recent study explores how musical performances communicate emotional expression, examining when and why emotional responses vary. His results showed that differences in timing played a more important role than differences in volume.
According to Levitin, the author of the bestselling books This is Your Brain on Music and The World in Six Songs, musical expression is largely communicated by the way the musician plays the notes. Levitin and his colleagues examined the way in which such variations served to communicate emotion by manipulating timing and amplitude in performances of classical piano pieces.
But how exactly can an emotional response to a musical performance be measured?
Using a disklavier, a specially modified piano keyboard with sensors beneath the keys. Levitin and his colleagues measured the precise and nuanced movements made by a concert pianist during his musical performance.
“We had a professional piano player from McGill’s Schulich School of Music come to the lab and play several pieces expressively,” said researcher Anna Tirovolas. “Then we systematically altered his performance to sound less expressive to see if people could hear the differences between them.”
Researcher Bianca Levy explained that participants listened to 30-second excerpts of these piano performances which varied in timing, loudness, and pedalling changes. They then rated how emotional they thought these performances were on a scale ranging from “not at all emotional” to “very emotional.”
Variation in timing had a greater effect on the subject’s ratings than amplitude modulation.
Levy was surprised that the results didn’t follow an exact linear trend.
“Participants were more sensitive to manipulations of timing and amplitude in the middle of the range than at the extremes,” she said.
Tirovolas said that although musicians appeared to be more sensitive to the cues, musicians and non-musicians alike could perceive very subtle differences in expressivity. Non-musicians, Levitin said, were consistently able to recognize and choose the more expressive excerpts.
“This tells us that even very subtle differences in performance are readily identified—even by average listeners,” he said. “I found that astonishing.”
Levitin added that one of the hopes of this kind of research is that it will aid in understanding the alchemy of a moving performance.
“It’s really a big step forward in capturing and quantifying why music is emotionally moving,” he said.