In a study designed to pinpoint the source of this and similarly irritating sounds, scientists found that the most obnoxious elements of the noises may be amplified by the shape of the human ear. The team will present its results at the 162nd meeting of the Acoustical Society of America (ASA), which runs from Oct. 31 – Nov. 4 in San Diego, Calif.
In the study, scientists removed information from actual audio clips of people scraping their nails or bits of chalk against a chalkboard. They then played these modified clips to willing participants. Half the study subjects were told what the sounds were; the other half thought that they were listening to selections from contemporary music. Scientists asked the participants to rate each sound’s unpleasantness, and also gauged the subjects’ stress responses to the noises by measuring their blood pressure, heart rate, and skin conductivity (a measure of sweating).
The human ear is known to be particularly sensitive to pitches in the mid- to low-level range of frequencies, between 2000 hertz and 4000 hertz, which is the peak of human hearing. It turns out that when scientists removed all the pitch information in this range from the audio recordings, the study participants rated the noises as more pleasant than other versions of the sounds. One explanation for people’s sensitivity to this band of frequencies is that sounds in this range are amplified due to the anatomy of the ear canal; they are literally louder to us than other sounds are. So chalkboard squeak may be irksome because the most obnoxious elements of the sound sit right in the sweet spot of human hearing.
“We supposed that frequencies in the low-mid range [of human hearing] would play a major role” in the unpleasantness of the sounds, said Michael Oehler, professor of media and music management at the University of Cologne in Germany, who will present his team’s findings at the conference. “But we did not know the exact range. Furthermore, the influence of pitch information was greater than we thought.”
Of potential interest to psychologists is the finding that participants who knew that the sounds they were hearing came from nails on a chalkboard rated these sounds more unpleasant, and experienced a higher degree of sweating, than the people who thought they were listening to music.
The presentation, “Psychoacoustics of chalkboard squeaking,” by Christoph Reuter and Michael Oehler will be at 3:15 p.m. on Thursday, Nov. 3 at the Town and Country Hotel and Convention Center in San Diego, Calif.
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Researchers create artificial materials atom-by-atom
28.03.2017 | Aalto University
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
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