Tuesday, 4 February 2014
However, in a new paper Jessica Phillips-Silver and her colleagues argue that the musical deficits associated with amusia may have been exaggerated. They've specifically explored the possibility that amusics have intact beat perception and dancing abilities. On conventional tests, amusia usually involves a beat perception deficit but the researchers say that could be because standard tests of beat perception require intact pitch perception, putting people with amusia at a disadvantage.
The investigation began by asking 10 people with amusia to detect the beat pattern of several melodies - specifically whether the beat was a march or a waltz. Tested the usual way, with melodies on a piano, and the people with amusia were impaired relative to normal controls. However, when they were tested with drums (an "unpitched" instrument), the people with amusia were just as able to detect beat patterns as controls.
Next, the researchers tested ten more people with amusia on their ability to detect beat patterns from the movement of their own body. Following the guidance of an experimenter, they bounced for two minutes in time with an ambiguous six-beat rhythm pattern. Crucially, they either bounced in such a way that they emphasised each other beat (known as duple form), or such that they emphasised every third beat (known as a triple form).
The test came next when they were played beat rhythms and asked to identify which had the same beat pattern (duple or triple form) that they'd just performed with their bouncing. People with amusia scored 84 per cent accuracy; eight normal controls scored 75 per cent accuracy. "These results show that pitch-deaf a musics can 'feel the beat' of music through body movement," the researchers said.
The final experiment tested the ability of ten people with amusia and eight controls to produce "dancelike" movements in time with the merengue dance song Suavemente by Elvis Crespo - a normal version and a drum version. The participants' rhythmical movements were tracked via a Nintendo Wii remote strapped to their bodies. The people with amusia struggled to dance in time to the music relative to controls. No real surprise there. However, they performed better than chance - their movements weren't completely out of synch with the music, especially for the drum version.
The researchers wondered if the reason the people with amusia struggled with the dancing might partly be down to lack of practice - most of them confessed that they rarely dance in everyday life. As a coda to the investigation, the Phillips-Silver and her colleagues followed up with one of their amusic participants a few months later and tested her dancing again (watch a video). This time she performed with the same timing ability as the healthy controls, suggesting that just a small amount of practice could make all the difference.
Reviewing their findings, the researchers said that there is a double-dissociation between pitch deafness and beat deafness. In fact it's recently been discovered that some people have beat perception deficits with intact pitch perception. These new results suggest that traditional amusia is associated with intact beat perception but impaired pitch perception. "Musicality has many facets," the researchers said, and to be pitch deaf does not mean you are completely unmusical. Indeed in different cultural contexts, such as traditional African vocal music, the researchers said people with amusia may not even be identified as having a problem.
"The present findings are encouraging for the pitch-deaf amusic population, who have historically been shunned from many music or dance activities," the researchers concluded. "If feeling the beat - and the dance-related skills that might develop out of listening and practicing to legitimate percussion music - is enough, then we might just consider that amusia does not mean 'unmusical'."
Phillips-Silver J, Toiviainen P, Gosselin N, and Peretz I (2013). Amusic does not mean unmusical: Beat perception and synchronization ability despite pitch deafness. Cognitive neuropsychology, 30 (5), 311-31 PMID: 24344816
Lost in music - Psychologist magazine article on amusia.
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.