Auditory illusions are false perceptions of a real sound or outside stimulus. These false perceptions are the equivalent of an

optical illusion Within visual perception, an optical illusion (also called a visual illusion) is an illusion caused by the visual system and characterized by a visual perception, percept that arguably appears to differ from reality. Illusions come in a wide v ...

: the listener hears either sounds which are not present in the stimulus, or sounds that should not be possible given the circumstance on how they were created. Humans are fairly susceptible to illusions, despite an innate ability to process complex stimuli. Confirmation bias is believed to be largely responsible for the inaccurate judgments that people make when evaluating information, given that humans typically interpret and recall information that appeals to their own biases. Amongst these misinterpretations, known as illusions, falls the category of auditory illusions. The brain uses multiple senses simultaneously to process information, spatial information is processed with greater detail and accuracy in vision than in hearing. Auditory illusions highlight areas where the

human ear An ear is the organ that enables hearing and, in mammals, body balance using the vestibular system. In mammals, the ear is usually described as having three parts—the outer ear, the middle ear and the inner ear. The outer ear consist ...

and

brain The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head ( cephalization), usually near organs for special ...

, as organic survival tools, differentiate from perfect audio receptors; this shows that it is possible for a human being to hear something that is not there and be able to react to the sound they supposedly heard. When someone is experiencing an auditory illusion, their brain is falsely interpreting its surroundings and distorting their perception of the world around them.

Causes

Many auditory illusions, particularly of music and of speech, result from hearing sound patterns that are highly probable, even though they are heard incorrectly. This is due to the influence of our knowledge and experience of many sounds we have heard. In order to prevent hearing echo created by perceiving multiple sounds coming from different spaces, the human auditory system relates the sounds as being from one source. However, that does not prevent people from being fooled by auditory illusions. Sounds that are found in words are called embedded sounds, and these sounds are the cause of some auditory illusions. A person's perception of a word can be influenced by the way they see the speaker's mouth move, even if the sound they hear is unchanged. For example, if someone is looking at two people saying "far" and "bar", the word they will hear will be determined by who they look at. If these sounds are played in a loop, the listener will be able to hear different words inside the same sound. People with brain damage can be more susceptible to auditory illusions and they can become more common for that person.

In music

Composers have long been using the spatial components of music to alter the overall sound experienced by the listener. One of the more common methods of sound synthesis is the use of combination tones. Combination tones are illusions that are not physically present as sound waves, but rather, they are created by one's own neuromechanics. According to Purwins, auditory illusions have been used effectively by the following:

Beethoven Ludwig van Beethoven (baptised 17 December 177026 March 1827) was a German composer and pianist. Beethoven remains one of the most admired composers in the history of Western music; his works rank amongst the most performed of the classic ...

(Leonore Overture), Berg (''

Wozzeck ''Wozzeck'' () is the first opera by the Austrian composer Alban Berg. It was composed between 1914 and 1922 and first performed in 1925. The opera is based on the drama ''Woyzeck'', which the German playwright Georg Büchner left incomplete at h ...

''), Krenek (''Spiritus Intelligentiae, Sanctus''), Ligeti (

Études Études is French for "studies". It is used as a name for several music or dance works, including: * ''Études'' (Chopin), three sets of studies for the piano by Frédéric Chopin, composed between 1829 and 1839 * ''Études'' (Debussy), a set of 1 ...

Violin Concerto A violin concerto is a concerto for solo violin (occasionally, two or more violins) and instrumental ensemble (customarily orchestra). Such works have been written since the Baroque music, Baroque period, when the solo concerto form was first dev ...

, Double Concerto, for flute, oboe and orchestra),

Honegger Arthur Honegger (; 10 March 1892 – 27 November 1955) was a Swiss composer who was born in France and lived a large part of his life in Paris. A member of Les Six, his best known work is probably '' Antigone'', composed between 1924 and 1927 ...

(''

Pacific 231 ''Pacific 231'' is an orchestral work by Arthur Honegger, written in 1923. It is one of his most frequently performed works. Description The popular interpretation of the piece is that it depicts a steam locomotive, one that is supported by th ...

''), and Stahnke (Partota 12). In the 2017 film, Dunkirk, Hans Zimmer used a Shepard Tone to create a constant feeling of stress and tension.

Examples

There are a multitude of examples out in the world of auditory illusions. These are examples of some auditory illusions: * Binaural beats * The constant spectrum melody * Deutsch's scale illusion * Franssen effect * Glissando illusion * Illusory continuity of tones * Illusory discontinuity * Hearing a

missing fundamental A harmonic sound is said to have a missing fundamental, suppressed fundamental, or phantom fundamental when its overtones suggest a fundamental frequency but the sound lacks a component at the fundamental frequency itself. The brain perceives the ...

frequency, given other parts of the harmonic series *Various psychoacoustic tricks of

lossy audio compression In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compressio ...

* McGurk effect * Octave illusion/Deutsch's high–low illusion * Auditory

pareidolia Pareidolia (; ) is the tendency for perception to impose a meaningful interpretation on a nebulous stimulus, usually visual, so that one sees an object, pattern, or meaning where there is none. Common examples are perceived images of animals, ...

: hearing indistinct voices in random noise. * The Shepard–Risset tone or scale, and the Deutsch tritone paradox * Speech-to-song illusion *

Yanny or Laurel Yanny or Laurel is an auditory illusion which became popular in May 2018, in which a short audio recording of speech can be heard as one of two words. 53 percent of over 500,000 respondents to a Twitter poll reported hearing a man saying the wor ...

References

External links

Diana Deutsch's Web Page
{{Music cognition Music psychology Psychoacoustics

Causes

In music

Examples

See also

References

External links