Auditory illusion

Last updated

Auditory illusions are illusions of real sound or outside stimulus. [1] These false perceptions are the equivalent of an optical illusion: 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. [2]

Contents

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. [3] 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. [4] [5] [6] Auditory illusions highlight areas where the human ear and brain, 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. [7]

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. [8] 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. [9] 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. [10] 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. [11] If these sounds are played in a loop, the listener will be able to hear different words inside the same sound. [12] People with brain damage can be more susceptible to auditory illusions and they can become more common for that person. [13]

In music

Composers have long been using the spatial components of music to alter the overall sound experienced by the listener. [14] 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. [15] According to Purwins, [16] auditory illusions have been used effectively by the following: Beethoven (Leonore Overture), Berg ( Wozzeck ), Krenek (Spiritus Intelligentiae, Sanctus), Ligeti (Études), Violin Concerto, Double Concerto, for flute, oboe and orchestra), Honegger ( Pacific 231 ), and Stahnke (Partota 12).

Examples

There are a multitude of examples out in the world of auditory illusions. These are examples of some auditory illusions:

See also

Related Research Articles

An illusion is a distortion of the senses, which can reveal how the mind normally organizes and interprets sensory stimulation. Although illusions distort the human perception of reality, they are generally shared by most people.

<span class="mw-page-title-main">Shepard tone</span> Auditory illusion

A Shepard tone, named after Roger Shepard, is a sound consisting of a superposition of sine waves separated by octaves. When played with the bass pitch of the tone moving upward or downward, it is referred to as the Shepard scale. This creates the auditory illusion of a tone that seems to continually ascend or descend in pitch, yet which ultimately gets no higher or lower.

<span class="mw-page-title-main">Pitch (music)</span> Perceptual property in music ordering sounds from low to high

Pitch is a perceptual property that allows sounds to be ordered on a frequency-related scale, or more commonly, pitch is the quality that makes it possible to judge sounds as "higher" and "lower" in the sense associated with musical melodies. Pitch is a major auditory attribute of musical tones, along with duration, loudness, and timbre.

<span class="mw-page-title-main">Missing fundamental</span> Acoustic phenomenon

The pitch being perceived with the first harmonic being absent in the waveform is called the missing fundamental phenomenon.

The octave illusion is an auditory illusion discovered by Diana Deutsch in 1973. It is produced when two tones that are an octave apart are repeatedly played in alternation ("high-low-high-low") through stereo headphones. The same sequence is played to both ears simultaneously; however when the right ear receives the high tone, the left ear receives the low tone, and conversely. Instead of hearing two alternating pitches, most subjects instead hear a single tone that alternates between ears while at the same time its pitch alternates between high and low.

The glissando illusion is an auditory illusion, created when a sound with a fixed pitch, such as a synthesized oboe tone, is played together with a sine wave gliding up and down in pitch, and they are both switched back and forth between stereo loudspeakers. The effect is that the oboe is heard as switching between loudspeakers while the sine wave is heard as joined together seamlessly, and as moving around in space in accordance with its pitch motion. Right-handers often hear the glissando as traveling from left to right as its pitch glides from low to high, and then back from right to left as its pitch glides from high to low.

<span class="mw-page-title-main">Tritone paradox</span> An auditory illusion perceived by some people to be rising in pich and by others to be falling

The tritone paradox is an auditory illusion in which a sequentially played pair of Shepard tones separated by an interval of a tritone, or half octave, is heard as ascending by some people and as descending by others. Different populations tend to favor one of a limited set of different spots around the chromatic circle as central to the set of "higher" tones. Roger Shepard in 1963 had argued that such tone pairs would be heard ambiguously as either ascending or descending. However, psychology of music researcher Diana Deutsch in 1986 discovered that when the judgments of individual listeners were considered separately, their judgments depended on the positions of the tones along the chromatic circle. For example, one listener would hear the tone pair C–F as ascending and the tone pair G–C as descending. Yet another listener would hear the tone pair C–F as descending and the tone pair G–C as ascending. Furthermore, the way these tone pairs were perceived varied depending on the listener's language or dialect.

<span class="mw-page-title-main">Illusory continuity of tones</span> Auditory illusion

The illusory continuity of tones is the auditory illusion caused when a tone is interrupted for a short time, during which a narrow band of noise is played. The noise has to be of a sufficiently high level to effectively mask the gap, unless it is a gap transfer illusion. Whether the tone is of constant, rising or decreasing pitch, the ear perceives the tone as continuous if the discontinuity is masked by noise. Because the human ear is very sensitive to sudden changes, however, it is necessary for the success of the illusion that the amplitude of the tone in the region of the discontinuity not decrease or increase too abruptly. While the inner mechanisms of this illusion is not well understood, there is evidence that supports activation of primarily the auditory cortex is present.

Deutsch's scale illusion is an auditory illusion in which two series of unconnected notes appear to combine into a single recognisable melody, when played simultaneously into the left and right ears of a listener.

<span class="mw-page-title-main">Jean-Claude Risset</span> French composer

Jean-Claude Raoul Olivier Risset was a French composer, best known for his pioneering contributions to computer music. He was a former student of André Jolivet and former co-worker of Max Mathews at Bell Labs.

Diana Deutsch is a British-American psychologist from London, England. She is a professor of psychology at the University of California, San Diego, and is a prominent researcher on the psychology of music. Deutsch is primarily known for her discoveries in music and speech illusions. She also studies the cognitive foundation of musical grammars, which consists of the way people hold musical pitches in memory, and how people relate the sounds of music and speech to each other. In addition, she is known for her work on absolute pitch, which she has shown is far more prevalent among speakers of tonal languages. Deutsch is the author of Musical Illusions and Phantom Words: How Music and Speech Unlock Mysteries of the Brain (2019), the editor for Psychology of Music, and also the compact discs Musical Illusions and Paradoxes (1995) and Phantom Words and Other Curiosities (2003).

Music psychology, or the psychology of music, may be regarded as a branch of both psychology and musicology. It aims to explain and understand musical behaviour and experience, including the processes through which music is perceived, created, responded to, and incorporated into everyday life. Modern music psychology is primarily empirical; its knowledge tends to advance on the basis of interpretations of data collected by systematic observation of and interaction with human participants. Music psychology is a field of research with practical relevance for many areas, including music performance, composition, education, criticism, and therapy, as well as investigations of human attitude, skill, performance, intelligence, creativity, and social behavior.

<span class="mw-page-title-main">Sound</span> Vibration that travels via pressure waves in matter

In physics, sound is a vibration that propagates as an acoustic wave through a transmission medium such as a gas, liquid or solid. In human physiology and psychology, sound is the reception of such waves and their perception by the brain. Only acoustic waves that have frequencies lying between about 20 Hz and 20 kHz, the audio frequency range, elicit an auditory percept in humans. In air at atmospheric pressure, these represent sound waves with wavelengths of 17 meters (56 ft) to 1.7 centimeters (0.67 in). Sound waves above 20 kHz are known as ultrasound and are not audible to humans. Sound waves below 20 Hz are known as infrasound. Different animal species have varying hearing ranges.

<span class="mw-page-title-main">Illusory conjunctions</span> Illusory conjunctions

Illusory conjunctions are psychological effects in which participants combine features of two objects into one object. There are visual illusory conjunctions, auditory illusory conjunctions, and illusory conjunctions produced by combinations of visual and tactile stimuli. Visual illusory conjunctions are thought to occur due to a lack of visual spatial attention, which depends on fixation and the amount of time allotted to focus on an object. With a short span of time to interpret an object, blending of different aspects within a region of the visual field – like shapes and colors – can occasionally be skewed, which results in visual illusory conjunctions. For example, in a study designed by Anne Treisman and Schmidt, participants were required to view a visual presentation of numbers and shapes in different colors. Some shapes were larger than others but all shapes and numbers were evenly spaced and shown for just 200 ms. When the participants were asked to recall the shapes they reported answers such as a small green triangle instead of a small green circle. If the space between the objects is smaller, illusory conjunctions occur more often.

The neuroscience of music is the scientific study of brain-based mechanisms involved in the cognitive processes underlying music. These behaviours include music listening, performing, composing, reading, writing, and ancillary activities. It also is increasingly concerned with the brain basis for musical aesthetics and musical emotion. Scientists working in this field may have training in cognitive neuroscience, neurology, neuroanatomy, psychology, music theory, computer science, and other relevant fields.

Psychoacoustics is the branch of psychophysics involving the scientific study of sound perception and audiology—how the human auditory system perceives various sounds. More specifically, it is the branch of science studying the psychological responses associated with sound. Psychoacoustics is an interdisciplinary field including psychology, acoustics, electronic engineering, physics, biology, physiology, and computer science.

<span class="mw-page-title-main">Pitch circularity</span> Fixed series of tones that appear to ascend or descend endlessly in pitch

Pitch circularity is a fixed series of tones that are perceived to ascend or descend endlessly in pitch. It's an example of an auditory illusion.

Selective auditory attention, or selective hearing, is a process of the auditory system where an individual selects or focuses on certain stimuli for auditory information processing while other stimuli are disregarded. This selection is very important as the processing and memory capabilities for humans have a limited capacity. When people use selective hearing, noise from the surrounding environment is heard by the auditory system but only certain parts of the auditory information are chosen to be processed by the brain.

Interindividual differences in perception describes the effect that differences in brain structure or factors such as culture, upbringing and environment have on the perception of humans. Interindividual variability is usually regarded as a source of noise for research. However, in recent years, it has become an interesting source to study sensory mechanisms and understand human behavior. With the help of modern neuroimaging methods such as fMRI and EEG, individual differences in perception could be related to the underlying brain mechanisms. This has helped to explain differences in behavior and cognition across the population. Common methods include studying the perception of illusions, as they can effectively demonstrate how different aspects such as culture, genetics and the environment can influence human behavior.

The speech-to-song illusion is an auditory illusion discovered by Diana Deutsch in 1995. A spoken phrase is repeated several times, without altering it in any way, and without providing any context. This repetition causes the phrase to transform perceptually from speech into song. Though mostly notable with languages that are non-tone, like English and German, it is possible to happen with tone languages, like Thai and Mandarin.

References

  1. Scott, Brian L.; Cole, Ronald A. (1972). "Auditory Illusions as Caused by Embedded Sounds". The Journal of the Acoustical Society of America. 51 (1A): 112. Bibcode:1972ASAJ...51R.112S. doi: 10.1121/1.1981302 .
  2. "Auditory illusion: How our brains can fill in the gaps to create continuous sound". Science Daily. Retrieved February 20, 2019.
  3. Brundage, Steven (2016). "Fooled By FLUENCY: UNDERSTANDING ILLUSIONS AND MISJUDGMENTS IN MUSIC LEARNING". American Music Teacher. 66 (2): 10–13. ISSN   0003-0112. JSTOR   26385737.
  4. Guttman, Sharon E.; Gilroy, Lee A.; Blake, Randolph (2005). "Hearing What the Eyes See: Auditory Encoding of Visual Temporal Sequences". Psychological Science. 16 (3): 228–235. doi:10.1111/j.0956-7976.2005.00808.x. ISSN   0956-7976. JSTOR   40064206. PMC   1431611 . PMID   15733204.
  5. O'Callaghan, Casey (2011). "Lessons from beyond vision (sounds and audition)". Philosophical Studies. 153 (1): 143–160. doi:10.1007/s11098-010-9652-7. ISSN   0031-8116. JSTOR   41487621. S2CID   7486290.
  6. Massaro, Dominic W., ed. (2007). "What Are Musical Paradox and Illusion?" (PDF). American Journal of Psychology. 120 (1). University of California, Santa Cruz: 124, 132. Archived (PDF) from the original on 2022-10-09. Retrieved 15 November 2013.
  7. KAYSER, CHRISTOPH (2007). "Listening with your Eyes". Scientific American Mind. 18 (2): 24–29. doi:10.1038/scientificamericanmind0407-24. ISSN   1555-2284. JSTOR   24939602.
  8. Deutsch, D. (2019). Musical Illusions and Phantom Words: How Music and Speech Unlock Mysteries of the Brain. Oxford University Press. ISBN   9780190206833. LCCN   2018051786.
  9. Deutsch, Diana (2010), "Auditory Illusions", Encyclopedia of Perception, Thousand Oaks, CA: SAGE Publications, Inc., doi:10.4135/9781412972000.n56, ISBN   978-1-4129-4081-8 , retrieved 2020-11-08
  10. "Auditory Illusions: How your ears can be fooled". hear.com. Retrieved 2019-04-19.
  11. "Do You Hear What I Hear? Amazing Auditory Illusions Explained". IFLScience. Retrieved 2019-04-21.
  12. Scott, Brian L.; Cole, Ronald A. (1972-01-01). "Auditory Illusions as Caused by Embedded Sounds". The Journal of the Acoustical Society of America. 51 (1A): 112. Bibcode:1972ASAJ...51R.112S. doi: 10.1121/1.1981302 . ISSN   0001-4966.
  13. Fukutake, Toshio; Hattori, Takamichi (1998-11-01). "Auditory illusions caused by a small lesion in the right medial geniculate body". Neurology. 51 (5): 1469–1471. doi:10.1212/WNL.51.5.1469. ISSN   0028-3878. PMID   9818885. S2CID   8928159.
  14. Begault, Durand R. (1990). "The Composition of Auditory Space: Recent Developments in Headphone Music". Leonardo. 23 (1): 45–52. doi:10.2307/1578465. ISSN   0024-094X. JSTOR   1578465. S2CID   191375886.
  15. Kendall, Gary S.; Haworth, Christopher; Cádiz, Rodrigo F. (2014). "Sound Synthesis with Auditory Distortion Products". Computer Music Journal. 38 (4): 5–23. doi: 10.1162/COMJ_a_00265 . hdl: 2027/spo.bbp2372.2012.016 . ISSN   0148-9267. JSTOR   24265446. S2CID   15744586.
  16. Purwins, Hendrik (2005). Profiles of pitch classes circularity of relative pitch and key-experiments, models, computational music analysis, and perspectives (PDF). pp. 110–120. Archived (PDF) from the original on 2022-10-09.