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Revision as of 20:33, 21 December 2016 by Martabarroso (talk | contribs)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)Scraping a chalkboard (also known as a blackboard) with the fingernails produces a sound and feeling which most people find extremely irritating. The basis of the innate reaction to the sound has been studied in the field of psychoacoustics (the branch of psychology concerned with the perception of sound and its physiological effects).
Primate heritage hypothesis
One explanation for the adverse reaction is that the sound is similar to the warning call of a primate back in the prehistoric times, more specifically to the call of a criature of macaque in danger. However, a study using Cotton-top tamarins, New World monkeys, found that they react similarly to both high-pitched sounds similar to fingernails on chalkboard, and to amplitude-matched white noise. In contrast, humans are less averse to the white noise than to scraping.
Many experts have opined that the reaction to this sound could be explained with the evolution of the ear. The ear has evolved to amplify the highest frequencies because they can be advantegous for survival; these can be found in a baby scream or the communication during the hunt.
Physical hypothesis
A 2011 study by musicologists Michael Oehler and Christoph Reuter led its authors to hypothesize that the unpleasantness of the sound is caused by acoustic resonance due to the shape of the human ear canal which amplifies certain frequencies, especially those in the range of 2000 to 4000 Hz (the median pitches mentioned above), at such a level that the sound would trigger pain in human ears. The study showed that when the pitches and frequency related to the scrapping were deleted, the human do not perceive the sound as irritable as it was.
Many participants of an experiment affirmed that part of the irritability of the sound is subject of suggestion, if it is supposed to be music, they do not feel such unpleasant. But not all of it is suggestion, researchers have proved that there is a physical reaction to it. The participants were monitored in order to perceive the alterations in certain indicators of stress such as heart rate, blood pressure and electric conductivity of skin. This last one was highly altered. List of the crankiest sounds to the human ear
Scrapping a chalkboard is not the most pernicious noise to the human ear. The scientists of the Wellcome Trust Centre for Neuroimaging at UCL and Newcastle University used functional magnetic resonance imaging (fMRI) to examine how the brains of 13 volunteers reacted to a range of sounds. From this, they concluded in a list of the 10 crankiest sounds to the human ear. 1 Knife on a bottle 2 Fork on a glass 3 Chalk on a blackboard 4 Ruler on a bottle
5 Fingernails on the chalkboard
6 Female screaming
7 Anglegrinder
8 Squealing brakes
9 Crying baby
10 Electric drill
See also
References
References
1 Jump up ^ Roger Highfield (2005-11-14). "Study seeks root of noises that annoy us". The Vancouver Sun. p. A6.
2 Jump up ^ Lynn Halpern; Randolph Blake; James Hillenbrand (1986). "Psychoacoustics of a chilling sound" (PDF). Perception & Psychophysics. Psychonomic Society. pp. 77–80.
3 Jump up ^ "Fingernails on a Chalkboard Garner Psychologist Ig Nobel Prize". 2006-10-08. Retrieved 2008-04-09.
4 Jump up ^ Trevor J. Cox (2008). "Scraping sounds and disgusting noises". Applied Acoustics. 69 (12): 1195–1204. doi:10.1016/j.apacoust.2007.11.004.
5 Jump up ^ Christoph Reuter; Michael Oehler. "Psychoacoustics of chalkboard squeaking". Journal of the Acoustical Society of America. 130: 2545. doi:10.1121/1.3655174.
6 Jump up ^ "Acoustical Society of America - Psychoacoustics of chalkboard squeaking". acoustics.org. Retrieved 10 October 2016.
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1.- van Kamp, I., & - Davies, H. (2013). - Noise and health in vulnerable groups: A review doi:- 10.4103/1463-1741.112361
2- PAUL ROZIN, JONATHAN HAIDT, and CLARK R. McCAULEY. (2008). Disgust. In MICHAEL LEWIS, JEANNETTE M. HAVILAND-JONES, AND LISA FELDMAN BARRETT (Ed.), Handbook of emotions (Third edition ed., pp. 757-777). United States of America: The Guilford Press.
3. Kumar, S., von Kriegstein, K., Friston, K., & Griffiths, T. D. (2012). Features versus feelings: Dissociable representations of the acoustic features and valence of aversive sounds. The Journal of Neuroscience, 32(41), 14184-14192. doi:10.1523/JNEUROSCI.1759-12.2012
4- Trevor J. Cox. (2008). Scrapping sounds and disgusting noises. Applied Acoustics, 69, 1195-1204. doi:doi:10.1016/j.apacoust.2007.11.004
6. Siegel, R. (November 9, 2011). Why nails on A chalkboard drives us crazy. Germany.
7- Cecil Adams. (1986, December 12). Why is the sound of fingernails scraping a blackboard so annoying?. The Straight Dope
8. Gónzalez, R. (2011). Why do you cringe at the sound of nails on a chalkboard?.
9- Today I found out. (2014). Why do fingernails on a chalkboard or scraping on a plate make us cringe?. Retrieved from http://www.todayifoundout.com/index.php/2014/05/fingernails-chalkboard-scraping-plate-make-us-cringe/
10. Why The Sound of Nails On Chalkboard Makes Us Cringe Matter of Facts. 29/06/2016 , 3mins 07secs https://youtube.com/2Bahqx9gHtY
(accessed 20/12/2016)