“I know only two tunes: one of them is ‘Yankee Doodle,’ and the other isn’t,” quipped Ulysses S. Grant. Grant famously disdained military music and many speculate that the 18th President of the United States suffered from tone-deafness or amusia.

“Amusia is a general term that applies to a group of musical deficits,” says Daniel J. Levitin, James McGill Professor of Psychology and Behavioural Neuroscience at McGill University in Montreal. 

Tone-deafness and amusia remain misunderstood. Bad singers could be one of four types—people unable to hear pitch; people who can’t capture rhythm; people who sing in a monotone; and people with voices that others don’t prefer, says Levitin. He peppers his explanation with song, singing “Twinkle, Twinkle Little Star” monotonically then performing it as if he is Bob Dylan (he does a pretty passable impression!).   

 “[Dylan] actually hits all the pitches, he is very precise; he has an unusual voice,” Levitin says. Critics call Dylan tone deaf simply because they dislike his voice.

Being a bad vocalist does not mean one is truly amusic. Being amusic means a person lacks musical ability; she might not be able to distinguish pitch or create different sounds.

“Normal people have some musical ability—if I play you a piece of music and I miss a note, you would know something wrong with that. Amusics can’t [tell],” says Psyche Loui, a neurology instructor at Beth Israel Deaconess Medical Center and Harvard Medical School in Boston. “The main compliant is that they cannot sing in tune.”

Anywhere from 4 to 9 percent of the population suffers from amusia. It’s difficult to obtain solid estimates because people dubbed tone-deaf earn the distinction because of terrible singing, not because they have been tested for amusia. (And these are real tests, including this one from the Music and Neuroimaging Laboratory, where Loui works http://musicianbrain.com/pitchtest/).

Loui says experts remain unsure about what causes amusia, but most believe a combination of environmental and genetic factors lead to disruptions in the brain, contributing to “unawareness and poor memory for sounds, especially pitches.”

Being amusic makes life tricky (and not just for those who suffer through a screeching rendition of “Call Me Maybe” at karaoke).

Many Asian and African languages are tonal and one word possesses different meanings based on how it’s pronounced. Loui, whose native language is Cantonese, provides an example. If she says ‘ma’ one way it means mother, if she says it with different inflection it means horse. Amusics who speak tonal languages are often unfairly pegged as having learning disabilities.

“If you cannot perceive tone, you can’t produce it,” says Loui.

In most languages, being unable to understand inflection or pitch can lead to misunderstandings, says Levitin. “A lot of emotion and intention is conveyed by tone,” he says.

People understand sarcasm because they hear the tone. For a person unable to discern such nuances, a conversation can be confusing.  

“[Amusia] is definitely a real phenomena and has neural underpinnings,” says Loui.

Related:

• Elvis song may reveal clues to genetic disorder
• Sounds delicious! New study shows link between pitch and flavor
• 4 reasons a song gets stuck in your head

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