Selective auditory attention

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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. [1] This selection is very important as the processing and memory capabilities for humans have a limited capacity. [2] 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.

Contents

Most often, auditory attention is directed at things people are most interested in hearing. [3] Selective hearing is not a physiological disorder but rather it is the capability of most humans to block out sounds and noise. It is the notion of ignoring certain things in the surrounding environment.

Bottleneck effect

In an article by Krans, Isbell, Giuliano, and Neville (2013), selective auditory attention can be seen through the process of the bottleneck effect, a process of the brain that inhibits processing of multiple stimuli. For example, a student is focused on a teacher giving a lesson and ignoring the sounds of classmates in a rowdy classroom (p. 53). As a result, the information given from the teacher is stored and encoded in the student's long term memory and the stimuli from the rowdy classroom is completely ignored as if it weren't present in the first place. A brain simply cannot for a sustained period collect all sensory information that is occurring in a chaotic real-world environment, so only the most relevant and important information is thoroughly processed by the brain. [4]

History

Early researches on selective auditory attention can be traced back to 1953, when Colin Cherry introduced the "cocktail party problem". [5] At the time, air traffic controllers at the control tower received messages from pilots through loudspeakers. Hearing mixed voices through a single loudspeaker made the task very difficult. [6] In Cherry's experiment, mimicking the problem faced by air traffic controllers, participants had to listen to two messages played simultaneously from one loudspeaker and repeat what they heard. [5] This was later termed the dichotic listening task. [7]

Though introduced by Colin Cherry, Donald Broadbent is often regarded as the first to systematically apply dichotic listening tests in his research. [8] Broadbent used the method of dichotic listening to test how participants selectively attend to stimuli when overloaded with auditory stimuli; Broadbent used his findings to develop the filter model of attention in 1958. [9] Broadbent theorized that the human information processing system has a "bottleneck" due to limited capacity and that the brain performs an "early selection" before processing auditory information. [10] Broadbent proposed that auditory information enters an unlimited sensory buffer and that one stream of information is filtered out and passes through the bottleneck to be cohesive, while all others that are not selected quickly decay in salience and are not processed. [11] Broadbent's model contradicts with the cocktail party phenomenon because Broadbent's model predicts that people would never respond to their names from unattended sources since unattended information is discarded before being processed.

Deutsch & Deutsch's late selection model that was proposed in 1963 is a competing model to Broadbent's early selection model. [12] Deutsch & Deutsch's model theorizes that all information and sensory input are attended to and processed for meaning. [12] Later in the processing routine, just before information enters the short-term memory, a filter analyzes the semantic characteristics of the information and lets stimuli containing relevant information pass through to short-term memory and removes irrelevant information. Deutsch & Deutsch's model for selective auditory attention suggests that weak response to unattended stimuli comes from an internal decision on informational relevance, where more important stimuli are prioritized to enter the working memory first.

In 1964, Anne Treisman, a graduate student of Broadbent, improved Broadent's theory and proposed her own attenuation model. [13] In Treisman's model, unattended information is attenuated, tuned down compared to attended information, but still processed. For example, imagine that you are exposed to three extraneous sources of sound in a coffee shop while ordering a drink (chatter, coffee brewer, music), Treisman's model indicates that you would still pick up on the latter three sounds while attending to the cashier, just that these extraneous sources of noise would be muffled as if their "volumes" were turned down. Treisman also suggests that a threshold mechanism exists in selective auditory attention in which words from the unattended stream of information can grab one's attention. Words of low threshold, higher level of meaning and importance, such as one's name and "watch out", redirects one's attention to where it is urgently required. [13]

Development in youth

Selective auditory attention is a component of auditory attention, which also includes arousal, orienting response, and attention span. Examining selective auditory attention has been known to be easier in children and adults compared to infants due to the limited ability to use and understand verbal commands. As a result, most of the understanding of auditory selection in infants is derived from other research, such as speech and language perception and discrimination. [14] However, small amounts of selection in infants has been recorded with preference over an infant's mother's voice compared to another female, [15] one's native language over a foreign one, [16] and speech directed towards infants instead of speech in between adults. [17]

As through age, older children have an increased ability to detect and select auditory stimuli compared to their younger counterparts. As a result, this makes older children perform better and make fewer errors in school. This suggests that selective auditory attention is an age dependent ability that increases based on improvements in automatic processing of information. [18] Another factor that could lead to this change is that older children are more equipped to understand a task and the reward and/or punishment for being able to understand and complete a task, thus eliminate unnecessary stimuli more frequently. [19]

Functional brain imaging studies of auditory attention

In recent years, neuroimaging tools such as PET (Positron Emission Tomography) and fMRI (Functional Magnetic Resonance Imaging) have been very successful in neural operations with high spatial resolution. Specifically, fMRI has been used to find evidence for attention effects in the auditory cortex in multiple studies. Another study based on "classical" dichotic selective listening paradigms has been proven to be successful as well. The findings showed that the effects were larger in the cortex contralateral to the direction of attention [20] [21] [22] [23] and were interpreted as "selective tuning of the left or right auditory cortices according to the direction of attention" [23]

Prevalence

The prevalence of selective hearing has not been clearly researched yet. However, there are some that have argued that the proportion of selective hearing is particularly higher in males than females. Ida Zündorf, Hans-Otto Karnath and Jörg Lewald carried out a study in 2010 which investigated the advantages and abilities males have in the localization of auditory information. [24] A sound localization task centered on the cocktail party effect was utilized in their study. The male and female participants had to try to pick out sounds from a specific source, on top of other competing sounds from other sources. The results showed that the males had a better performance overall. Female participants found it more difficult to locate target sounds in a multiple-source environment. Zündorf et al. suggested that there may be sex differences in the attention processes that helped locate the target sound from a multiple-source auditory field. While men and women do have some differences when it comes to selective auditory hearing, they both struggle when presented with the challenge of multitasking, especially when tasks that are to be attempted concurrently are very similar in nature (Dittrich, and Stahl, 2012, p. 626). [25]

Disorder status

Selective hearing is not known to be a disorder of the physiological or psychological aspect. Under the World Health Organization (WHO), a hearing disorder happens when there is a complete loss of hearing in the ears. It means the loss of the ability to hear. Technically speaking, selective hearing is not "deafness" to a certain sound message. Rather, it is the selectivity of an individual to attend audibly to a sound message. The whole sound message is physically heard by the ear but the brain systematically filters out unwanted information to focus on relevant important portions of the message. Therefore, selective hearing should not be confused as a physiological hearing disorder. [26] Selective auditory attention is a normal sensory process of the brain, and there can be abnormalities related to this process in people with sensory processing disorders such as autism, attention deficit hyperactive disorder, [27] post traumatic stress disorder, [28] schizophrenia, [27] selective mutism, [29] and in stand-alone auditory processing disorders. [30]

See also

Related Research Articles

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Attention or focus, is the concentration of awareness on some phenomenon to the exclusion of other stimuli. It is the selective concentration on discrete information, either subjectively or objectively. William James (1890) wrote that "Attention is the taking possession by the mind, in clear and vivid form, of one out of what seem several simultaneously possible objects or trains of thought. Focalization, concentration, of consciousness are of its essence." Attention has also been described as the allocation of limited cognitive processing resources. Attention is manifested by an attentional bottleneck, in terms of the amount of data the brain can process each second; for example, in human vision, less than 1% of the visual input data stream of 1MByte/sec can enter the bottleneck, leading to inattentional blindness.

<span class="mw-page-title-main">McGurk effect</span> Perceptual illusion

The McGurk effect is a perceptual phenomenon that demonstrates an interaction between hearing and vision in speech perception. The illusion occurs when the auditory component of one sound is paired with the visual component of another sound, leading to the perception of a third sound. The visual information a person gets from seeing a person speak changes the way they hear the sound. If a person is getting poor-quality auditory information but good-quality visual information, they may be more likely to experience the McGurk effect. Integration abilities for audio and visual information may also influence whether a person will experience the effect. People who are better at sensory integration have been shown to be more susceptible to the effect. Many people are affected differently by the McGurk effect based on many factors, including brain damage and other disorders.

<span class="mw-page-title-main">Auditory cortex</span> Part of the temporal lobe of the brain

The auditory cortex is the part of the temporal lobe that processes auditory information in humans and many other vertebrates. It is a part of the auditory system, performing basic and higher functions in hearing, such as possible relations to language switching. It is located bilaterally, roughly at the upper sides of the temporal lobes – in humans, curving down and onto the medial surface, on the superior temporal plane, within the lateral sulcus and comprising parts of the transverse temporal gyri, and the superior temporal gyrus, including the planum polare and planum temporale.

<span class="mw-page-title-main">Anne Treisman</span> English cognitive psychologist (1935–2018)

Anne Marie Treisman was an English psychologist who specialised in cognitive psychology.

<span class="mw-page-title-main">Cocktail party effect</span> Ability of the brain to focus on a single auditory stimulus by filtering out background noise

The cocktail party effect refers to a phenomenon wherein the brain focuses a person's attention on a particular stimulus, usually auditory. This focus excludes a range of other stimuli from conscious awareness, as when a partygoer follows a single conversation in a noisy room. This ability is widely distributed among humans, with most listeners more or less easily able to portion the totality of sound detected by the ears into distinct streams, and subsequently to decide which streams are most pertinent, excluding all or most others.

Sensory processing is the process that organizes and distinguishes sensation from one's own body and the environment, thus making it possible to use the body effectively within the environment. Specifically, it deals with how the brain processes multiple sensory modality inputs, such as proprioception, vision, auditory system, tactile, olfactory, vestibular system, interoception, and taste into usable functional outputs.

Sensory gating describes neural processes of filtering out redundant or irrelevant stimuli from all possible environmental stimuli reaching the brain. Also referred to as gating or filtering, sensory gating prevents an overload of information in the higher cortical centers of the brain. Sensory gating can also occur in different forms through changes in both perception and sensation, affected by various factors such as "arousal, recent stimulus exposure, and selective attention."

The mismatch negativity (MMN) or mismatch field (MMF) is a component of the event-related potential (ERP) to an odd stimulus in a sequence of stimuli. It arises from electrical activity in the brain and is studied within the field of cognitive neuroscience and psychology. It can occur in any sensory system, but has most frequently been studied for hearing and for vision, in which case it is abbreviated to vMMN. The (v)MMN occurs after an infrequent change in a repetitive sequence of stimuli For example, a rare deviant (d) stimulus can be interspersed among a series of frequent standard (s) stimuli. In hearing, a deviant sound can differ from the standards in one or more perceptual features such as pitch, duration, loudness, or location. The MMN can be elicited regardless of whether someone is paying attention to the sequence. During auditory sequences, a person can be reading or watching a silent subtitled movie, yet still show a clear MMN. In the case of visual stimuli, the MMN occurs after an infrequent change in a repetitive sequence of images.

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Auditory processing disorder (APD), rarely known as King-Kopetzky syndrome or auditory disability with normal hearing (ADN), is a neurodevelopmental disorder affecting the way the brain processes sounds. Individuals with APD usually have normal structure and function of the ear, but cannot process the information they hear in the same way as others do, which leads to difficulties in recognizing and interpreting sounds, especially the sounds composing speech. It is thought that these difficulties arise from dysfunction in the central nervous system. This is, in part, essentially a failure of the cocktail party effect found in most people.

Dichotic pitch is a pitch heard due to binaural processing, when the brain combines two noises presented simultaneously to the ears. In other words, it cannot be heard when the sound stimulus is presented monaurally but, when it is presented binaurally a sensation of a pitch can be heard. The binaural stimulus is presented to both ears through headphones simultaneously, and is the same in several respects except for a narrow frequency band that is manipulated. The most common variation is the Huggins Pitch, which presents white-noise that only differ in the interaural phase relation over a narrow range of frequencies. For humans, this phenomenon is restricted to fundamental frequencies lower than 330 Hz and extremely low sound pressure levels. Experts investigate the effects of the dichotic pitch on the brain. For instance, there are studies that suggested it evokes activation at the lateral end of Heschl's gyrus.

Dichotic listening is a psychological test commonly used to investigate selective attention and the lateralization of brain function within the auditory system. It is used within the fields of cognitive psychology and neuroscience.

Spatial hearing loss refers to a form of deafness that is an inability to use spatial cues about where a sound originates from in space. Poor sound localization in turn affects the ability to understand speech in the presence of background noise.

Amblyaudia is a term coined by Dr. Deborah Moncrieff to characterize a specific pattern of performance from dichotic listening tests. Dichotic listening tests are widely used to assess individuals for binaural integration, a type of auditory processing skill. During the tests, individuals are asked to identify different words presented simultaneously to the two ears. Normal listeners can identify the words fairly well and show a small difference between the two ears with one ear slightly dominant over the other. For the majority of listeners, this small difference is referred to as a "right-ear advantage" because their right ear performs slightly better than their left ear. But some normal individuals produce a "left-ear advantage" during dichotic tests and others perform at equal levels in the two ears. Amblyaudia is diagnosed when the scores from the two ears are significantly different with the individual's dominant ear score much higher than the score in the non-dominant ear Researchers interested in understanding the neurophysiological underpinnings of amblyaudia consider it to be a brain based hearing disorder that may be inherited or that may result from auditory deprivation during critical periods of brain development. Individuals with amblyaudia have normal hearing sensitivity but have difficulty hearing in noisy environments like restaurants or classrooms. Even in quiet environments, individuals with amblyaudia may fail to understand what they are hearing, especially if the information is new or complicated. Amblyaudia can be conceptualized as the auditory analog of the better known central visual disorder amblyopia. The term “lazy ear” has been used to describe amblyaudia although it is currently not known whether it stems from deficits in the auditory periphery or from other parts of the auditory system in the brain, or both. A characteristic of amblyaudia is suppression of activity in the non-dominant auditory pathway by activity in the dominant pathway which may be genetically determined and which could also be exacerbated by conditions throughout early development.

Sensory-motor coupling is the coupling or integration of the sensory system and motor system. Sensorimotor integration is not a static process. For a given stimulus, there is no one single motor command. "Neural responses at almost every stage of a sensorimotor pathway are modified at short and long timescales by biophysical and synaptic processes, recurrent and feedback connections, and learning, as well as many other internal and external variables".

Attenuation theory, also known as Treisman’s Attenuation Model, is a model of selective attention proposed by Anne Treisman, and can be seen as a revision of Donald Broadbent's filter model. Treisman proposed attenuation theory as a means to explain how unattended stimuli sometimes came to be processed in a more rigorous manner than what Broadbent's filter model could account for. As a result, attenuation theory added layers of sophistication to Broadbent's original idea of how selective attention might operate: claiming that instead of a filter which barred unattended inputs from ever entering awareness, it was a process of attenuation. Thus, the attenuation of unattended stimuli would make it difficult, but not impossible to extract meaningful content from irrelevant inputs, so long as stimuli still possessed sufficient "strength" after attenuation to make it through a hierarchical analysis process.

Broadbent's filter model is an early selection theory of attention.

Neville Moray was a British-born Canadian psychologist. He served as an academic and professor at the Department of Psychology of the University of Surrey, known from his 1959 research of the cocktail party effect.

Perceptual load theory is a psychological theory of attention. It was presented by Nilli Lavie in the mid-nineties as a potential resolution to the early/late selection debate.

<span class="mw-page-title-main">Auditosensory cortex</span>

Auditosensory cortex is the part of the auditory system that is associated with the sense of hearing in humans. It occupies the bilateral primary auditory cortex in the temporal lobe of the mammalian brain. The term is used to describe Brodmann area 42 together with the transverse temporal gyri of Heschl. The auditosensory cortex takes part in the reception and processing of auditory nerve impulses, which passes sound information from the thalamus to the brain. Abnormalities in this region are responsible for many disorders in auditory abilities, such as congenital deafness, true cortical deafness, primary progressive aphasia and auditory hallucination.

References

  1. ↑ Gomes, Hilary; Molholm, Sophie; Christodoulou, Christopher; Ritter, Walter; Cowan, Nelson (2000-01-01). "The development of auditory attention in children". Frontiers in Bioscience-Landmark. 5 (3): 108–120. doi: 10.2741/gomes . ISSN   2768-6701.
  2. ↑ Schneider, Walter; Shiffrin, Richard M. (January 1977). "Controlled and automatic human information processing: I. Detection, search, and attention". Psychological Review. 84 (1): 1–66. doi:10.1037/0033-295X.84.1.1. ISSN   1939-1471.
  3. ↑ Bess FH, Humes L (2008). Audiology: The Fundamentals. Philadelphia: Lippincott Williams & Wilkins.
  4. ↑ Karns, Christina M.; Isbell, Elif; Giuliano, Ryan J.; Neville, Helen J. (June 2015). "Auditory attention in childhood and adolescence: An event-related potential study of spatial selective attention to one of two simultaneous stories". Developmental Cognitive Neuroscience. 13: 53–67. doi:10.1016/j.dcn.2015.03.001. PMC   4470421 . PMID   26002721.
  5. 1 2 Cherry C (5 May 1953). "Some experiments on the recognition of speech, with one and two ears" (PDF).
  6. ↑ Kantowitz BH, Sorkin RD (1983). Human factors : understanding people-system relationships. New York: Wiley. ISBN   0-471-09594-X. OCLC   8866672.
  7. ↑ Revlin R (2013). Cognition : theory and practice. New York, NY: Worth Publishers. ISBN   978-0-7167-5667-5. OCLC   793099349.
  8. ↑ Hugdahl K (2015). "Dichotic Listening and Language: Overview". International Encyclopedia of the Social & Behavioral Sciences. Elsevier. pp. 357–367. doi:10.1016/b978-0-08-097086-8.54030-6. ISBN   978-0-08-097087-5.
  9. ↑ Moray N (1995). "Donald E. Broadbent: 1926-1993". The American Journal of Psychology. 108 (1): 117–21. PMID   7733412.
  10. ↑ Goldstein S, Naglieri JA (19 November 2013). Handbook of Executive Functioning. New York, NY. ISBN   978-1-4614-8106-5. OCLC   866899923.{{cite book}}: CS1 maint: location missing publisher (link)
  11. ↑ Broadbent DE (22 October 2013). Perception and communication. Oxford, England. ISBN   978-1-4832-2582-1. OCLC   899000591.{{cite book}}: CS1 maint: location missing publisher (link)
  12. 1 2 Deutsch JA, Deutsch D (January 1963). "Some theoretical considerations". Psychological Review. 70: 80–90. doi:10.1037/h0039515. PMID   14027390.
  13. 1 2 Treisman AM (May 1969). "Strategies and models of selective attention". Psychological Review. 76 (3): 282–99. doi:10.1037/h0027242. PMID   4893203.
  14. ↑ Gomes, Hilary; Molholm, Sophie; Christodoulou, Christopher; Ritter, Walter; Cowan, Nelson (2000-01-01). "The development of auditory attention in children". Frontiers in Bioscience-Landmark. 5 (3): 108–120. doi: 10.2741/gomes . ISSN   2768-6701.
  15. ↑ DeCasper, Anthony J.; Fifer, William P. (1980-06-06). "Of Human Bonding: Newborns Prefer Their Mothers' Voices". Science. 208 (4448): 1174–1176. doi:10.1126/science.7375928. ISSN   0036-8075.
  16. ↑ Mehler, Jacques; Jusczyk, Peter; Lambertz, Ghislaine; Halsted, Nilofar; Bertoncini, Josiane; Amiel-Tison, Claudine (1988-07-01). "A precursor of language acquisition in young infants". Cognition. 29 (2): 143–178. doi:10.1016/0010-0277(88)90035-2. ISSN   0010-0277.
  17. ↑ Fernald, Anne (1985-04-01). "Four-month-old infants prefer to listen to motherese". Infant Behavior and Development. 8 (2): 181–195. doi:10.1016/S0163-6383(85)80005-9. ISSN   0163-6383.
  18. ↑ The Development of Speech Perception: The Transition from Speech Sounds to Spoken Words. The MIT Press. 1994-03-08. doi:10.7551/mitpress/2387.001.0001. ISBN   978-0-262-27408-1.
  19. ↑ Gibson, Eleanor; Rader, Nancy (1979), Hale, Gordon A.; Lewis, Michael (eds.), "Attention", Attention and Cognitive Development, Boston, MA: Springer US, pp. 1–21, doi:10.1007/978-1-4613-2985-5_1, ISBN   978-1-4613-2985-5 , retrieved 2023-10-23
  20. ↑ Pugh, Kenneth R.; Shaywitz, Bennett A.; Shaywitz, Sally E.; Fulbright, Robert K.; Byrd, Dani; Skudlarski, Pawel; Shankweiler, Donald P.; Katz, Leonard; Constable, R.Todd; Fletcher, Jack; Lacadie, Cheryl; Marchione, Karen; Gore, John C. (December 1996). "Auditory Selective Attention: An fMRI Investigation". NeuroImage. 4 (3): 159–173. doi: 10.1006/nimg.1996.0067 . ISSN   1053-8119.
  21. ↑ O'Leary, Daniel S.; Andreasen, Nancy C.; Hurtig, Richard R.; Hichwa, Richard D.; Watkins, G.Leonard; Boles Ponto, Laura L.; Rogers, Margaret; Kirchner, Peter T. (April 1996). "A Positron Emission Tomography Study of Binaurally and Dichotically Presented Stimuli: Effects of Level of Language and Directed Attention". Brain and Language. 53 (1): 20–39. doi:10.1006/brln.1996.0034. ISSN   0093-934X.
  22. ↑ Tzourio, N.; El Massioui, F.; Crivello, F.; Joliot, M.; Renault, B.; Mazoyer, B. (January 1997). "Functional Anatomy of Human Auditory Attention Studied with PET". NeuroImage. 5 (1): 63–77. doi:10.1006/nimg.1996.0252. ISSN   1053-8119.
  23. 1 2 Alho, Kimmo; Medvedev, Sviatoslav V.; Pakhomov, Sergei V.; Roudas, Marina S.; Tervaniemi, Mari; Reinikainen, Kalevi; Zeffiro, Thomas; Näätänen, Risto (January 1999). "Selective tuning of the left and right auditory cortices during spatially directed attention". Cognitive Brain Research. 7 (3): 335–341. doi:10.1016/s0926-6410(98)00036-6. ISSN   0926-6410.
  24. ↑ Zündorf IC, Karnath HO, Lewald J (June 2011). "Male advantage in sound localization at cocktail parties". Cortex; A Journal Devoted to the Study of the Nervous System and Behavior. 47 (6): 741–9. doi:10.1016/j.cortex.2010.08.002. PMID   20828679. S2CID   206983792.
  25. ↑ Dittrich K, Stahl C (June 2012). "Selective impairment of auditory selective attention under concurrent cognitive load". Journal of Experimental Psychology. Human Perception and Performance. 38 (3): 618–27. doi:10.1037/a0024978. PMID   21928926.
  26. ↑ "Deafness and hearing impairment". World Health Organization. WHO. 2012.
  27. 1 2 Vlcek P, Bob P, Raboch J (2014-07-14). "Sensory disturbances, inhibitory deficits, and the P50 wave in schizophrenia". Neuropsychiatric Disease and Treatment. 10: 1309–15. doi: 10.2147/ndt.s64219 . PMC   4106969 . PMID   25075189.
  28. ↑ Javanbakht A, Liberzon I, Amirsadri A, Gjini K, Boutros NN (October 2011). "Event-related potential studies of post-traumatic stress disorder: a critical review and synthesis". Biology of Mood & Anxiety Disorders. 1 (1): 5. doi: 10.1186/2045-5380-1-5 . PMC   3377169 . PMID   22738160.
  29. ↑ Arie, Miri; Henkin, Yael; Lamy, Dominique; Tetin-Schneider, Simona; Apter, Alan; Sadeh, Avi; Bar-Haim, Yair (February 1, 2007). "Reduced Auditory Processing Capacity During Vocalization in Children With Selective Mutism". Biological Psychiatry. 61 (3): 419–421. doi:10.1016/j.biopsych.2006.02.020. PMID   16616723. S2CID   21750355 . Retrieved July 12, 2020.
  30. ↑ American Academy of Audiology. "Clinical Practice Guidelines: Diagnosis, Treatment and Management of Children and Adults with Central Auditory" (PDF). Retrieved 16 January 2017.
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