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| The '''sound of fingernails scraping chalkboard''' is a noise produced when ] are dragged across a ], producing ]. The noise is often considered one of the world's most unpleasant sounds. Its effect was famously demonstrated in a scene from the film '']'', where ] character brings a noisy room to silence with a long scrape across a blackboard.<ref></ref> | The '''sound of fingernails scraping chalkboard''' is a noise produced when ] are dragged across a ], producing ]. The noise is often considered one of the world's most unpleasant sounds. Its effect was famously demonstrated in a scene from the film '']'', where ] character brings a noisy room to silence with a long scrape across a blackboard.<ref></ref> | ||
Revision as of 19:40, 21 April 2008
The sound of fingernails scraping chalkboard is a noise produced when fingernails are dragged across a chalkboard, producing vibration. The noise is often considered one of the world's most unpleasant sounds. Its effect was famously demonstrated in a scene from the film Jaws, where Robert Shaw's character brings a noisy room to silence with a long scrape across a blackboard.
Why it repulses humans
It has been suggested that people's aversion to the sound is because it sounds like the warning call of a primate ancestor. However, a study using Cottontop Tamarins, a kind of New World Monkey, found that they react similarly to both screeching sounds similar to fingernails on chalkboard, and to amplitude-matched white noise. This is different from how humans react, as humans are less averse to the white noise than to scraping.
A 1986 study attempted to determine why the sound was so unpleasant. It used a tape-recording of a three-pronged garden tool similar to a fork being "grided" across a chalkboard, which reproduces the sound of fingernails on chalkboard. It also used other sounds for comparison. They then manipulated the recording to remove the lowest, highest, and middle pitches. The results were then played back. It was determined that the middle pitches are what make the sound of fingernails scraping chalkboard so bad, not the highest ones as previously thought. The authors hypothesized that it might be due to predation early in human evolution; the sound bore some resemblences to the alarm call of macaque monkeys, or it may have been similar to the call of some predator. This research won one of the authors, Randolph Blake, an Ig Nobel Prize in 2006. More recent research contradicts this hypothesis.
Is it really the worst sound?
A study was conducted by Trevor Cox, a scientist at the University of Salford, to determine the most repulsive sound in the world. It involved uploading clips of 34 sounds onto the website sound101.org and having people from around the world rate them.
Fingernails scraping chalkboard was not the worst sound, only coming in 16th place. The worst sound was that of someone vomiting, followed by microphone feedback, babies crying, and a miscellaneous "scrapping (sic) sound".
Although the results are thought to be influenced by culture, Cox felt that the disgust reaction to certain sounds was evolutionary in nature. The disgust reaction to disease probably evolved to avoid getting sick. Females were in general more disgusted than males; it is speculated that this is due to females not only preventing themselves from getting sick, but also their offspring. In all, females rated more sounds worse than males, although the sound of a baby crying was a notable exception. Disgust also decreased with age.
References
- ^ Roger Highfield (2005-11-14). "Study seeks root of noises that annoy us". Vancouver Sun. p. A6.
- Lynn Halpern, Randolph Blake, & James Hillenbrand (1986). "Psychoacoustics of a chilling sound" (PDF). Perception and Psychophysics. Psychonomic Society. pp. 77–80.
{{cite web}}: CS1 maint: multiple names: authors list (link) - "Fingernails on a Chalkboard Garner Psychologist Ig Nobel Prize". 2006-10-08. Retrieved 2008-04-09.
- Trevor J. Cox (2008), "Scraping sounds and disgusting noises", Applied Acoustics
- ^ Brandon Miller & Fred Koschmann (2007). "FYI". Popular Mechanics. p. 102.
{{cite news}}: Unknown parameter|month=ignored (help) - ^ Cox, Trevor. "About Bad Vibes". Bad Vibes Website. Salford University’s Acoustic Research Centre. Retrieved 2008-04-06.
{{cite web}}: Cite has empty unknown parameters:|month=and|coauthors=(help)
External links
- Sound101 Bad Vibes
- The Straight Dope: Why is the sound of fingernails scraping a blackboard so annoying?