250 px, noise_polluted_urban_surroundings_than_quieter_ones_to_help_overcome_the_

noise_polluted_urban_surroundings_than_quieter_ones_to_help_overcome_the_auditory_masking">noise_pollution.html"_;"title="Great_tits_sing_at_a_higher_frequency_in_noise_pollution">noise_polluted_urban_surroundings_than_quieter_ones_to_help_overcome_the_auditory_masking_that_would_otherwise_impair_other_birds_hearing_their_bird_vocalization.html" "title="auditory_masking.html" ;"title="noise_pollution.html" ;"title="Great tits sing at a higher frequency in noise pollution">noise polluted urban surroundings than quieter ones to help overcome the auditory masking">noise_pollution.html" ;"title="Great tits sing at a higher frequency in noise pollution">noise polluted urban surroundings than quieter ones to help overcome the auditory masking that would otherwise impair other birds hearing their bird vocalization">song A song is a musical composition intended to be performed by the human voice. This is often done at distinct and fixed pitches (melodies) using patterns of sound and silence. Songs contain various forms, such as those including the repetiti ...

. Although great tits achieve a change in song frequency by switching song types, in other urban birds the change in frequency might be related to the Lombard effect. For instance, in humans, the Lombard effect results in speakers adjusting frequency The Lombard effect or Lombard reflex is the Volition (psychology), involuntary tendency of speakers to increase their vocal effort when speaking in loudness, loud noise to enhance the audibility of their

voice The human voice consists of sound made by a human being using the vocal tract, including talking, singing, laughing, crying, screaming, shouting, humming or yelling. The human voice frequency is specifically a part of human sound producti ...

. This change includes not only loudness but also other acoustic features such as pitch, rate, and duration of

syllable A syllable is a unit of organization for a sequence of speech sounds typically made up of a syllable nucleus (most often a vowel) with optional initial and final margins (typically, consonants). Syllables are often considered the phonological ...

s. This compensation effect maintains the auditory

signal-to-noise Signal-to-noise ratio (SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. SNR is defined as the ratio of signal power to the noise power, often expressed in decib ...

ratio of the speaker's

spoken words Language is a structured system of communication. The structure of a language is its grammar and the free components are its vocabulary. Languages are the primary means by which humans communicate, and may be conveyed through a variety of me ...

. The effect links to the needs of effective communication, as there is a reduced effect when words are repeated or lists are read where communication intelligibility is not important. Since the effect is involuntary it is used as a means to detect malingering in those simulating

hearing loss Hearing loss is a partial or total inability to hear. Hearing loss may be present at birth or acquired at any time afterwards. Hearing loss may occur in one or both ears. In children, hearing problems can affect the ability to acquire spoken l ...

. Research on birds and monkeys find that the effect also occurs in the vocalizations of animals. The effect was discovered in 1909 by Étienne Lombard, a French

otolaryngologist Otorhinolaryngology ( , abbreviated ORL and also known as otolaryngology, otolaryngology–head and neck surgery (ORL–H&N or OHNS), or ear, nose, and throat (ENT)) is a surgical subspeciality within medicine that deals with the surgical a ...

Lombard speech

Listeners hear a speech recorded with background noise better than they hear a speech which has been recorded in quiet with masking noise applied afterwards. This is because changes between normal and Lombard speech include: * increase in phonetic fundamental frequencies * shift in energy from low frequency bands to middle or high bands * increase in sound intensity * increase in

vowel A vowel is a syllabic speech sound pronounced without any stricture in the vocal tract. Vowels are one of the two principal classes of speech sounds, the other being the consonant. Vowels vary in quality, in loudness and also in quantity (len ...

duration * spectral tilting * shift in

formant In speech science and phonetics, a formant is the broad spectral maximum that results from an acoustic resonance of the human vocal tract. In acoustics, a formant is usually defined as a broad peak, or local maximum, in the spectrum. For harmoni ...

center frequencies for F1 (mainly) and F2 * the duration of

content word Content words, in linguistics, are words that possess semantic content and contribute to the meaning of the sentence in which they occur. In a traditional approach, nouns were said to name objects and other entities, lexical verbs to indicate acti ...

s are prolonged to a greater degree in noise than

function word In linguistics, function words (also called functors) are words that have little lexical meaning or have ambiguous meaning and express grammatical relationships among other words within a sentence, or specify the attitude or mood of the speake ...

s * greater lung volumes are used, * it is accompanied by larger facial movements, though these do not aid as much as sound changes These changes cannot be controlled by instructing a person to speak as they would in silence, though people can learn control with feedback. The Lombard effect also occurs following

laryngectomy Laryngectomy is the removal of the larynx and separation of the airway from the mouth, nose and esophagus. In a total laryngectomy, the entire larynx is removed (including the vocal folds, hyoid bone, epiglottis, thyroid and cricoid cartilage and ...

when people following

speech therapy Speech is a human vocal communication using language. Each language uses phonetic combinations of vowel and consonant sounds that form the sound of its words (that is, all English words sound different from all French words, even if they are th ...

talk with esophageal speech.

Mechanisms

The intelligibility of an individual's own vocalization can be adjusted with audio-vocal reflexes using their own hearing (private loop), or it can be adjusted indirectly in terms of how well listeners can hear the vocalization (public loop). Both processes are involved in the Lombard effect.

Private loop

A speaker can regulate their vocalizations, particularly their amplitude relative to background noise, with reflexive auditory feedback. Such auditory feedback is known to maintain the production of vocalization since deafness affects the vocal acoustics of both humans and songbirds Changing the auditory feedback also changes vocalization in human speech or bird song. Neural circuits have been found in the

brainstem The brainstem (or brain stem) is the posterior stalk-like part of the brain that connects the cerebrum with the spinal cord. In the human brain the brainstem is composed of the midbrain, the pons, and the medulla oblongata. The midbrain is ...

that enable such reflex adjustment.

Public loop

A speaker can regulate their vocalizations at higher cognitive level in terms of observing its consequences on their audience's ability to hear it. In this auditory self-monitoring adjusts vocalizations in terms of learnt associations of what features of their vocalization, when made in noise, create effective and efficient communication. The Lombard effect has been found to be greatest upon those words that are important to the listener to understand a speaker suggesting such cognitive effects are important.

Development

Both private and public loop processes exist in children. There is a development shift however from the Lombard effect being linked to acoustic self-monitoring in young children to the adjustment of vocalizations to aid its intelligibility for others in adults.

Neurology

The Lombard effect depends upon audio-vocal neurons in the periolivary region of the superior olivary complex and the adjacent pontine

reticular formation The reticular formation is a set of interconnected nuclei that are located throughout the brainstem. It is not anatomically well defined, because it includes neurons located in different parts of the brain. The neurons of the reticular formatio ...

. It has been suggested that the Lombard effect might also involve the higher cortical areas that control these lower brainstem areas.

Choral singing

Choral singers experience reduced

feedback Feedback occurs when outputs of a system are routed back as inputs as part of a chain of cause-and-effect that forms a circuit or loop. The system can then be said to ''feed back'' into itself. The notion of cause-and-effect has to be handled ...

due to the sound of other singers upon their own voice. This results in a tendency for people in choruses to sing at a louder level if it is not controlled by a conductor. Trained soloists can control this effect but it has been suggested that after a concert they might speak more loudly in noisy surroundings, such as after-concert parties. The Lombard effect also occurs to those playing instruments such as the

guitar The guitar is a fretted musical instrument that typically has six strings. It is usually held flat against the player's body and played by strumming or plucking the strings with the dominant hand, while simultaneously pressing selected string ...

Animal vocalization

Noise has been found to affect the vocalizations of animals that vocalize against a background of human

noise pollution Noise pollution, also known as environmental noise or sound pollution, is the propagation of noise with ranging impacts on the activity of human or animal life, most of them are harmful to a degree. The source of outdoor noise worldwide is mai ...

. Experimentally, the Lombard effect has also been found in the vocalization of: *

Budgerigar The budgerigar ( ; ''Melopsittacus undulatus''), also known as the common parakeet or shell parakeet, is a small, long-tailed, seed-eating parrot usually nicknamed the budgie ( ), or in American English, the parakeet. Budgies are the only spe ...

s * Canaries *

Cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...

s *

Chicken The chicken (''Gallus gallus domesticus'') is a domesticated junglefowl species, with attributes of wild species such as the grey and the Ceylon junglefowl that are originally from Southeastern Asia. Rooster or cock is a term for an adu ...

s *

Common marmoset The common marmoset (''Callithrix jacchus'') also called white-tufted marmoset or white-tufted-ear marmoset is a New World monkey. It originally lived on the northeastern coast of Brazil, in the states of Piaui, Paraiba, Ceará, Rio Grande do ...

s *

Cottontop tamarin The cotton-top tamarin (''Saguinus oedipus'') is a small New World monkey weighing less than . This New World monkey can live up to 24 years, but most of them die by 13 years. One of the smallest primates, the cotton-top tamarin is easily reco ...

s * Japanese quail * Nightingales *

Rhesus macaque The rhesus macaque (''Macaca mulatta''), colloquially rhesus monkey, is a species of Old World monkey. There are between six and nine recognised subspecies that are split between two groups, the Chinese-derived and the Indian-derived. Generally ...

s *

Squirrel monkey Squirrel monkeys are New World monkeys of the genus ''Saimiri''. ''Saimiri'' is the only genus in the subfamily Saimirinae. The name of the genus is of Tupi origin (''sai-mirím'' or ''çai-mbirín'', with ''sai'' meaning 'monkey' and ''mirím'' ...

Zebra finch The zebra finches are two species of estrildid finch in the genus ''Taeniopygia'' found in Australia and Indonesia. They are seed-eaters that travel in large flocks. The species are: Previously, both species were classified as a single specie ...

es *

Beluga whale The beluga whale () (''Delphinapterus leucas'') is an Arctic and sub-Arctic cetacean. It is one of two members of the family Monodontidae, along with the narwhal, and the only member of the genus ''Delphinapterus''. It is also known as the ...

s * Pale spear-nosed bats * Túngara frogs

References

{{DEFAULTSORT:Lombard Effect Phonetics Human voice Animal communication Human communication Noise pollution