Lombard effect - AbsoluteAstronomy.com

The Lombard effect or Lombard reflex is the involuntary

Involuntary

Involuntary is the antonym of voluntary. An involuntary action is one that occurs without volition or will; see volition and will . Involuntary may also refer to:*Involuntary , a 2008 Swedish film by Ruben Östlund...

tendency of speakers to increase their vocal effort

Vocal effort

Vocal effort is a quantity varied by speakers when adjusting to an increase or decrease in the communication distance. The communication distance is the distance between the speaker and the listener. Vocal effort is a subjective physiological quantity, and is mainly dependent on subglottal...

when speaking in loud

Loudness

Loudness is the quality of a sound that is primarily a psychological correlate of physical strength . More formally, it is defined as "that attribute of auditory sensation in terms of which sounds can be ordered on a scale extending from quiet to loud."Loudness, a subjective measure, is often...

noise to enhance the audibility of their voice

Human voice

The human voice consists of sound made by a human being using the vocal folds for talking, singing, laughing, crying, screaming, etc. Its frequency ranges from about 60 to 7000 Hz. The human voice is specifically that part of human sound production in which the vocal folds are the primary...

. This change includes not only loudness but also other acoustic features such as pitch

Pitch (music)

Pitch is an auditory perceptual property that allows the ordering of sounds on a frequency-related scale.Pitches are compared as "higher" and "lower" in the sense associated with musical melodies,...

and rate and duration of sound syllable

Syllable

A syllable is a unit of organization for a sequence of speech sounds. For example, the word water is composed of two syllables: wa and ter. A syllable is typically made up of a syllable nucleus with optional initial and final margins .Syllables are often considered the phonological "building...

s. This compensation effect results in an increase in the auditory signal-to-noise ratio of the speaker’s spoken words

Speech

Speech is the human faculty of speaking.It may also refer to:* Public speaking, the process of speaking to a group of people* Manner of articulation, how the body parts involved in making speech are manipulated...

.

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 also involuntary it is used as a means to detect malingering

Malingering

Malingering is a medical term that refers to fabricating or exaggerating the symptoms of mental or physical disorders for a variety of "secondary gain" motives, which may include financial compensation ; avoiding school, work or military service; obtaining drugs; getting lighter criminal sentences;...

in those simulating hearing loss. Research upon birds and monkeys finds that the effect also occurs in the vocalizations of nonhuman animals.

The effect was discovered in 1909 by Étienne Lombard

Étienne Lombard

thumb|200px|Étienne Lombard], Étienne Lombard was a French otolaryngologist and surgeon who discovered the Lombard effect, in which a person's voice is involuntarily raised when speaking in a loud environment....

, a French otolaryngologist.

Lombard speech

When heard with noise, listeners hear speech recorded in noise better compared to that speech which has been recorded in quiet and then played given with the same level of masking noise

Auditory masking

Auditory masking occurs when the perception of one sound is affected by the presence of another sound.- Simultaneous masking :Simultaneous masking is when a sound is made inaudible by a "masker", a noise or unwanted sound of the same duration as the original sound.-Critical bandwidth:If two sounds...

. Changes between normal and Lombard speech include:

increase in phonetic fundamental frequencies
Fundamental frequency
The fundamental frequency, often referred to simply as the fundamental and abbreviated f0, is defined as the lowest frequency of a periodic waveform. In terms of a superposition of sinusoids The fundamental frequency, often referred to simply as the fundamental and abbreviated f0, is defined as the...
shift in energy from low frequency bands to middle or high bands,
increase in sound intensity
Sound intensity
Sound intensity or acoustic intensity is defined as the sound power Pac per unit area A. The usual context is the noise measurement of sound intensity in the air at a listener's location.-Acoustic intensity:...

,
increase in vowel
Vowel
In phonetics, a vowel is a sound in spoken language, such as English ah! or oh! , pronounced with an open vocal tract so that there is no build-up of air pressure at any point above the glottis. This contrasts with consonants, such as English sh! , where there is a constriction or closure at some...

duration,
spectral tilting,
shift in formant
Formant
Formants are defined by Gunnar Fant as 'the spectral peaks of the sound spectrum |P|' of the voice. In speech science and phonetics, formant is also used to mean an acoustic resonance of the human vocal tract...

center frequencies for F1 (mainly) and F2.
the duration of content words are prolonged to a greater degree in noise than function word
Function word
Function words are words that have little lexical meaning or have ambiguous meaning, but instead serve to express grammatical relationships with other words within a sentence, or specify the attitude or mood of the speaker...

s.
great lung volumes are used,
it is accompanied by larger facial movements
Facial expression
A facial expression one or more motions or positions of the muscles in the skin. These movements convey the emotional state of the individual to observers. Facial expressions are a form of nonverbal communication. They are a primary means of conveying social information among humans, but also occur...

but these do not aid as much as its 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

Laryngectomy is the removal of the larynx and separation of the airway from the mouth, nose and esophagus. The laryngectomee breathes through an opening in the neck, a stoma. This procedure is usually performed in cases of laryngeal cancer...

when people following speech therapy talk with esophageal speech

Esophageal speech

Esophageal speech, also known as esophageal voice, is a method of speech production that involves oscillation of the esophagus. This contrasts with traditional laryngeal speech which involves oscillation of the vocal folds. Instead, air is injected into the upper esophagus and then released in a...

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 its 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 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

Child development

Child development stages describe theoretical milestones of child development. Many stage models of development have been proposed, used as working concepts and in some cases asserted as nativist theories....

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

Reticular formation

The reticular formation is a part of the brain that is involved in actions such as awaking/sleeping cycle, and filtering incoming stimuli to discriminate irrelevant background stimuli...

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

Choral singing

Choral singer

Choir

A choir, chorale or chorus is a musical ensemble of singers. Choral music, in turn, is the music written specifically for such an ensemble to perform.A body of singers who perform together as a group is called a choir or chorus...

s experience reduced feedback

Feedback

Feedback describes the situation when output from an event or phenomenon in the past will influence an occurrence or occurrences of the same Feedback describes the situation when output from (or information about the result of) an event or phenomenon in the past will influence an occurrence or...

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

Conducting

Conducting is the art of directing a musical performance by way of visible gestures. The primary duties of the conductor are to unify performers, set the tempo, execute clear preparations and beats, and to listen critically and shape the sound of the ensemble...

. Trained soloists can control this effect but it has been suggested that after a concert they might speak more loudly in noisy surrounding as in after-concert parties.

The Lombard effect also occurs to those playing instruments such as the guitar

Guitar

The guitar is a plucked string instrument, usually played with fingers or a pick. The guitar consists of a body with a rigid neck to which the strings, generally six in number, are attached. Guitars are traditionally constructed of various woods and strung with animal gut or, more recently, with...

Animal vocalization

Noise has been found to effect the vocalizations of animals that vocalize against a background of human noise pollution

Noise pollution

Noise pollution is excessive, displeasing human, animal or machine-created environmental noise that disrupts the activity or balance of human or animal life...

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

Budgerigar
Budgerigar
The Budgerigar , also known as Common Pet Parakeet or Shell Parakeet informally nicknamed the budgie, is a small, long-tailed, seed-eating parrot, and the only species in the Australian genus Melopsittacus...

s
Cat
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...

s
Chicken
Chicken
The chicken is a domesticated fowl, a subspecies of the Red Junglefowl. As one of the most common and widespread domestic animals, and with a population of more than 24 billion in 2003, there are more chickens in the world than any other species of bird...

s
Common marmoset
Common Marmoset
The common 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 Norte, Pernambuco, Alagoas and Bahia...

s
Cottontop tamarin
Cottontop Tamarin
The cotton-top tamarin , also known as the Pinché tamarin, is a small New World monkey weighing less than 1 lb...

s
Japanese quail
Japanese Quail
The Japanese Quail, also known as Coturnix Quail, Coturnix japonica, is a species of Old World Quail found in East Asia. They are a migratory species, breeding in Manchuria, southeastern Siberia, northern Japan, and the Korean Peninsula, and wintering in the south of Japan and southern China. They...
Nightingale
Nightingale
The Nightingale , also known as Rufous and Common Nightingale, is a small passerine bird that was formerly classed as a member of the thrush family Turdidae, but is now more generally considered to be an Old World flycatcher, Muscicapidae...

s
Rhesus Macaque
Rhesus Macaque
The Rhesus macaque , also called the Rhesus monkey, is one of the best-known species of Old World monkeys. It is listed as Least Concern in the IUCN Red List of Threatened Species in view of its wide distribution, presumed large population, and its tolerance of a broad range of habitats...

s
Squirrel monkey
Squirrel monkey
The squirrel monkeys are the New World monkeys of the genus Saimiri. They are the only genus in the subfamily Saimirinae.Squirrel monkeys live in the tropical forests of Central and South America in the canopy layer. Most species have parapatric or allopatric ranges in the Amazon, while S...

.
Zebra finch
Zebra Finch
The Zebra Finch, Taeniopygia guttata, is the most common and familiar estrildid finch of Central Australia and ranges over most of the continent, avoiding only the cool moist south and the tropical far north. It also can be found natively in Indonesia and East Timor...

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