Human echolocation

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Human echolocation is a technique that some blind people use to get an idea of ​​their surroundings. This technique can be taught and practiced as part of orientation and mobility training . A distinction is made between passive and active echolocation. In contrast to localization using reflected secondary signals, there is localization , i.e. direct directional hearing using primary signals.

Active and passive echolocation

Passive echolocation uses the sound sources present in the environment and their echoes to generate a vague idea of ​​the environment. The echoes are interpreted as acoustic signals by the user's brain and must be processed intellectually.

The active echolocation Klicksonar , on the other hand, is a technology that emits sound with a subtle click of the tongue and evaluates the echoes that fall back, comparable to the echolocation used by bats and dolphins . After regular practice generates a with the See similar image of the environment in the visual cortex of the brain. The brain separates the echo signals as visually usable information from the other acoustic information and processes them in the respective brain areas.

Use of echolocation to orient blind people

The earlier blind toddlers are introduced to the technology of active echolocation in a playful way, the easier it is for them to integrate it into their orientation and navigation. With the help of Klicksonar, a trained person can use the echoes of objects in a differentiated manner and thus perceive the position, the density and, in some cases, the size of the objects. Due to the physical limits, the optimal range is approx. 50 cm to 300 meters. The technique is used by trained blind people to move autonomously, to orientate themselves and to avoid obstacles. The echolocation technique can also be learned by sighted people.

For several years there have been electronic aids to support echolocation. These are small, compact devices that emit a very defined, sharply focused sound beam. This makes it easier to learn the technology because the echoes thrown back by objects also sound much louder and clearer. In addition, the achievable perception performance is significantly increased, which means that small, narrow or finely structured objects such as fences, thin posts or branches that protrude in the path can still be perceived well at distances of a few meters. The disadvantage is that an electronic aid has to be carried along.

The click sonar technique was systematically analyzed by Daniel Kish (* 1966), the teaching of the technique methodized and made popular in the USA. Completely blind, Daniel Kish taught himself as a child to get information about his surroundings by clicking his tongue and listening to the echoes. Kish has trained over a thousand other blind people to use echolocation since 1991. To this end, he and two of his students founded the non-profit organization World Access for the Blind . The technology has been taught in Germany since 2011. The German donation-financed partner organization Anderessehen e. V. has taken on the task of implementing the Klicksonar technology in German-speaking countries as the standard orientation method in the training of blind children by informing those affected, doing media work and training those affected and trainers.

In April 2011 Daniel Kish taught the first two blind toddlers in Germany between the ages of 2 and 4. Subsequently, on the initiative of Anderessehen e. V. in November 2011 for the first time taught 100  early childhood supporters , mobility trainers, blind people and parents of blind children in Germany from Daniel Kish in Klicksonar technology. Since April 2012, all early supporters and mobility trainers for the blind in Austria have been instructed in the technology by the Federal Institute for Education for the Blind and the Contrast association and pass the method on to blind children and adults.

ARD filmed a documentary about the beginnings of Klicksonar technology in German-speaking countries in 2011 and broadcast it in June 2012. It was also available as an audio version for blind people.

Artistic positions

As early as 1968, under the influence of the work of Donald R. Griffin , the sound artist and composer Alvin Lucier wrote his piece Vespers , which is located on the borderline of performance , for “any number of people who want to show their respect to all living beings who populate the dark and live in have developed a high level of accuracy in echo sounding over the years [...]. ”With the help of probes, small technical devices that emit clicks, or other signal transmitters, the participants should orient themselves in an artistically controlled situation exclusively acoustically in the room.

On January 2, 2014, the film Imagine by Polish director Andrzej Jakimowski was released in German cinemas, in which, among other things, human echolocation plays a role.

Individual evidence

  1. ↑ Lore Thaler, Stephen R. Arnott, Melvyn A. Goodale: Neural Correlates of Natural Human Echolocation in Early and Late Blind Echolocation Experts . At: PLoSONE.org. 6 (5): e20162, 2011.
  2. ↑ Kate Ravilious: Humans Can Learn to “See” With Sound, Study Says . At: NationalGeographic.com. July 6, 2009.
  3. ↑ Brain research: How blind people orient themselves using echolocation . At: Spiegel.de . May 6, 2011.
  4. ↑ Acoustical awareness . At: Anderes-Sehen.de. Retrieved December 20, 2015.
  5. ↑ Daniel Kish: Flash Sonar: Understanding and Applying Sonar Imaging to Mobility . At: nfb.org. Future Reflections, Volume 30: 1 (Winter 2011).
  6. ↑ Spanish scientists develop echo-location in humans . At: EurekAlert.org. June 30, 2009.
  7. ↑ Project blind assistance. Institute for Technology and Computer Science (ITI), Technische Hochschule Mittelhessen , Giessen, 2018, accessed on May 9, 2019 .
  8. ↑ Hans-Werner Hunziker : Magic of hearing: Unconscious strategies of hearing perception . Transmedia Stäubli Verlag AG, Zurich 2011, ISBN 978-3-7266-0087-7 .
  9. ↑ Manfred Dworschak: Perception: The Bat Girls . At: Spiegel.de. Issue 24, 2011.
  10. ^ Official start of the click sonar technology in Germany . At: Anderes-Sehen.de. Retrieved December 20, 2015.
  11. ↑ Those who see with their ears. New ways for blind children . At: Programm.ARD.de . June 9, 2012.
  12. ↑ With audio description: Those who see with their ears. ( Memento from June 3, 2013 in the Internet Archive ) ARD report as audio film, no longer publicly available in the archive.
  13. ^ Alvin Lucier : Reflections. Interviews, notations, texts. 2nd, extended edition, MusikTexte , Cologne 2005, pp. 304–307 (verbal notation) and pp. 74–85 (interview), ISBN 3-9803151-2-6 .

literature

  • Siegfried Saerberg: Straight ahead is always straight ahead - a lifeworld ethnography with a blind spatial orientation. Konstanz, UVK-Verl.-Ges., ISBN 3-89669-679-3 .
  • Martinez Rojas et al. a .: Physical Analysis of Several Organic Signals for Human Echolocation: oral vacuum pulses. In: Acta Acustica united with Acustica 2009. Volume 2, No. 95 ( ISSN  1610-1928 ), pp. 325-330.
  • Richard Ernst Sergel: The blind people's sense of distance . In: The Gazebo . Issue 18, 1867, pp. 287 ( full text [ Wikisource ]).
  • Perception. The bat man . In: Der Spiegel . No. 22 , 2004 ( online ).

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