Tone deafness is the lack of relative pitch, or the inability to distinguish between musical notes that is not due to the lack of musical training or education. Tone deafness is also known variously as amusia, tune deafness, "tin ear", dysmelodia and dysmusia.
The ability to hear and reproduce relative pitch, as with other musical abilities, is present in all societies and in most humans. The hearing impairment appears to be genetically influenced, though it can also result from brain damage. Someone who is unable to reproduce pitches because of a lack of musical training would not be considered tone deaf in a medical sense. Tone deafness affects the ability to hear relative pitch changes produced by a musical instrument.
However, tone deaf people seem to be[not in citation given] disabled only when it comes to music, as they can fully interpret the prosody or intonation of human speech. Tone deafness has a strong negative correlation with belonging to societies with tonal languages. This could be evidence that the ability to reproduce and distinguish between notes may be a learned skill, but may conversely suggest that the genetic predisposition towards accurate pitch discrimination may influence the linguistic development of a population towards tonality. A correlation between allele frequencies and linguistic typological features has been recently discovered, supporting the latter hypothesis.
Tone deafness is also associated with other musical-specific impairments, such as inability to keep time with music (the lack of rhythm), or the inability to remember or recognize a song. These disabilities can appear separately but some research shows that they are more likely to appear in tone-deaf people. Experienced musicians, such as W. A. Mathieu, have addressed tone deafness in adults as correctable with training.
In nine of ten tone deaf people, the superior arcuate fasciculus in the right hemisphere could not be detected, suggesting a disconnection between the posterior superior temporal gyrus and the posterior inferior frontal gyrus. Researchers suggested the posterior superior temporal gyrus was the origin of the disorder.
See also 
- Amusia, the medical loss of musical ability
- Absolute pitch, the rare ability to name a musical note when played or sung
- Relative pitch, the normal human ability to accurately distinguish pitch intervals
- Tonal memory
- Musical aptitude
- Beat deafness
- Deafness, the inability to hear sound
- Color blindness
Notable tone-deaf people 
- Charles Darwin
- Alfred Duff Cooper
- Ulysses S. Grant
- Florence Foster Jenkins
- Alfonso XIII of Spain
- Isabel Paterson
- William Lawrence Bragg
- J. B. S. Haldane
- Che Guevara
- W. D. Hamilton
- John Dewey
- William Butler Yeats 
- Wendy Richard
- Ann Widdecombe 
- Pope Francis 
- Dediu, Dan; D. Robert Ladd (June 2007). "Linguistic tone is related to the population frequency of the adaptive haplogroups of two brain size genes, ASPM and Microcephalin". Proceedings of the National Academy of Sciences 104 (26): 10944–9. doi:10.1073/pnas.0610848104. PMC 1904158. PMID 17537923. Retrieved 18 July 2008.
- Ayotte, Julie; Isabelle Peretz and Krista Hyde (February 2002). "Congenital amusia: a group study of adults afflicted with a music-specific disorder". Brain 125 (2): 238–51. doi:10.1093/brain/awf028. PMID 11844725. Retrieved 18 July 2008.
- Mathieu, W. A. "Tone-Deaf Choir". Retrieved 26 February 2009.
- Loui P, Alsop D, Schlaug S. (2009). Tone Deafness: A New Disconnection Syndrome? Journal of Neuroscience, 29(33):10215–10220 doi:10.1523/JNEUROSCI.1701-09.2009
- LaFee, Scott (9 February 2009). "Darwin's Legacy: Natural selections". The San Diego Union-Tribune. Retrieved 10 February 2009.
- Norwich, John Julius. The Duff Cooper Diaries 1915-1951.Phoenix, 2006, ISBN 978-0-7538-2105-3. P.109.
- Sacks, Oliver; Musicophilia: Tales of Music and the Brain; p 108 ISBN 1-4000-3353-5
- MacIntyre, F. Gwynplaine (23 June 2004). "Happy in her work". Daily News. Archived from the original on 10 August 2004. Retrieved 23 December 2008.
- See Isaac Asimov's Book of Facts
- Cox, Stephen (2004). The Woman and the Dynamo: Isabel Paterson and the Idea of America. New Brunswick, New Jersey, USA: Transaction Publishers. p. 85. ISBN 978-0-7658-0241-5.
- Hunter, Graeme K.; Light is a messenger: the life and science of William Lawrence Bragg; p. 158. ISBN 0-19-852921-X
- Crow, James Franklin and Dove, William F.; Perspectives on genetics: anecdotal, historical, and critical commentaries; p. 254. ISBN 0-299-16604-X
- Baril, Daniel (12 April 1999). "Le cerveau musical". Forum 33 (26) (Université de Montréal). Retrieved 19 July 2008
- Hamilton, W. D. and Ridley, Mark; Narrow Roads of Gene Land: The Collected Papers of W. D. Hamilton Volume 3; p. 7. ISBN 0-19-856690-5
- Zeltner, Philip N.; John Dewey's Aesthetic Philosophy; p. 93. ISBN 90-6032-029-8
- The New York Times http://www.nytimes.com/books/first/b/brown-yeats.html
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- Desert Island Discs
- "Five Minutes With: Ann Widdecombe". BBC. 16 July 2011.
- "Can't chant, can't speak English? Pope says it's because he's tone-deaf". Catholic News Service. 02 April 2013.
- University of Newcastle: Musical Listening Test
- BBC: Listening Displeasure
- NPR: Test for tone deafness (requires RealAudio player)
- MedicineNet: Amusia
- NIH: Distorted Tunes Test
- The Listening Book: Tone-Deaf Choir audio description by W. A. Mathieu