Lombard effect

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Great tits sing at a higher frequency in noise polluted urban surroundings than quieter ones to help overcome the auditory masking that would otherwise impair other birds hearing their song.[1] Although great tits achieve a change in song frequency by switching song types,[2] in other urban birds the change in frequency might be related to the Lombard effect.[3] For instance, in humans, the Lombard effect results in speakers adjusting frequency

The Lombard effect or Lombard reflex is the involuntary tendency of speakers to increase their vocal effort when speaking in loud noise to enhance the audibility of their voice.[4] This change includes not only loudness but also other acoustic features such as pitch, rate, and duration of sound syllables.[5][6] This compensation effect results in an increase in the auditory signal-to-noise ratio of the speaker’s spoken words.

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.[4] Since the effect is also involuntary it is used as a means to detect malingering in those simulating hearing loss. Research upon birds[7][8] and monkeys [9] finds that the effect also occurs in the vocalizations of nonhuman animals.

The effect was discovered in 1909 by Étienne Lombard, a French otolaryngologist.[4][10]

Lombard speech[edit]

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. Changes between normal and Lombard speech include:[5][6]

These changes cannot be controlled by instructing a person to speak as they would in silence, though people can learn control with feedback.[14]

The Lombard effect also occurs following laryngectomy when people following speech therapy talk with esophageal speech.[15]

Mechanisms[edit]

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).[4] Both processes are involved in the Lombard effect.

Private loop[edit]

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[16] and songbirds[17] Changing the auditory feedback also changes vocalization in human speech[18] or bird song.[19] Neural circuits have been found in the brainstem that enable such reflex adjustment.[20]

Public loop[edit]

A speaker can regulate their vocalizations at higher cognitive level in terms of observing its consequences on their audience’s ability to hear it.[4] 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.[11]

Development[edit]

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.[21]

Neurology[edit]

The Lombard effect depends upon audio-vocal neurons in the periolivary region of the superior olivary complex and the adjacent pontine reticular formation.[20] It has been suggested that the Lombard effect might also involve the higher cortical areas[4] that control these lower brainstem areas.[22]

Choral singing[edit]

Choral singers experience reduced feedback due to the sound of other singers upon their own voice.[23] 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 surrounding as in after-concert parties.[23]

The Lombard effect also occurs to those playing instruments such as the guitar[24]

Animal vocalization[edit]

Noise has been found to affect the vocalizations of animals that vocalize against a background of human noise pollution.[25] Experimentally, the Lombard effect has also been found in the vocalization of:

See also[edit]

References[edit]

  1. ^ Slabbekoorn H, Peet M (July 2003). "Ecology: Birds sing at a higher pitch in urban noise". Nature 424 (6946): 267. doi:10.1038/424267a. PMID 12867967. 
  2. ^ Halfwerk, W; Slabbekoorn (2009). "A behavioural mechanism explaining noise-dependent pitch shift in urban birdsong". Animal Behaviour 78 (6): 1301–1307. doi:10.1016/j.anbehav.2009.09.015. 
  3. ^ Nemeth E., E; Brumm H. (2010). "Birds and Anthropogenic Noise: Are Urban Songs Adaptive?". American Naturalist 176 (4): 465–475. doi:10.1086/656275. PMID 20712517. 
  4. ^ a b c d e f Lane H, Tranel B (1971). "The Lombard sign and the role of hearing in speech". J Speech Hear Res 14 (4): 677–709. 
  5. ^ a b Junqua JC (January 1993). "The Lombard reflex and its role on human listeners and automatic speech recognizers". J. Acoust. Soc. Am. 93 (1): 510–24. doi:10.1121/1.405631. PMID 8423266. 
  6. ^ a b Summers WV, Pisoni DB, Bernacki RH, Pedlow RI, Stokes MA (September 1988). "Effects of noise on speech production: acoustic and perceptual analyses". J. Acoust. Soc. Am. 84 (3): 917–28. doi:10.1121/1.396660. PMID 3183209. 
  7. ^ a b Brumm H (June 2004). "Causes and consequences of song amplitude adjustment in a territorial bird: a case study in nightingales". An. Acad. Bras. Cienc. 76 (2): 289–95. doi:10.1590/s0001-37652004000200017. PMID 15258642. 
  8. ^ Lombard É (1911). "Le signe de l'élévation de la voix". Annales des Maladies de L'Oreille et du Larynx. XXXVII (2): 101–9. 
  9. ^ a b Patel R, Schell KW (February 2008). "The influence of linguistic content on the Lombard effect". J. Speech Lang. Hear. Res. 51 (1): 209–20. doi:10.1044/1092-4388(2008/016). PMID 18230867. 
  10. ^ Winkworth AL, Davis PJ (February 1997). "Speech breathing and the Lombard effect". J. Speech Lang. Hear. Res. 40 (1): 159–69. PMID 9113867. 
  11. ^ Vatikiotis-Bateson E, Chung V, Lutz K, Mirante N, Otten J, Tan J (2006). "Auditory, but perhaps not visual, processing of Lombard speech". J. Acoust. Soc. Am. 119 (5): 3444. doi:10.1121/1.4786950. 
  12. ^ Pick HL, Siegel GM, Fox PW, Garber SR, Kearney JK (February 1989). "Inhibiting the Lombard effect". J. Acoust. Soc. Am. 85 (2): 894–900. doi:10.1121/1.397561. PMID 2926004. 
  13. ^ Zeine L, Brandt JF (September 1988). "The Lombard effect on alaryngeal speech". J Commun Disord 21 (5): 373–83. doi:10.1016/0021-9924(88)90022-6. PMID 3183082. 
  14. ^ Waldstein RS (November 1990). "Effects of postlingual deafness on speech production: implications for the role of auditory feedback". J. Acoust. Soc. Am. 88 (5): 2099–114. doi:10.1121/1.400107. PMID 2269726. 
  15. ^ Konishi M (August 1965). "Effects of deafening on song development in American robins and black-headed grosbeaks". Z Tierpsychol 22 (5): 584–99. PMID 5879978. 
  16. ^ Siegel GM, Schork EJ, Pick HL, Garber SR (September 1982). "Parameters of auditory feedback". J Speech Hear Res 25 (3): 473–5. PMID 7176623. 
  17. ^ Leonardo A, Konishi M (June 1999). "Decrystallization of adult birdsong by perturbation of auditory feedback". Nature 399 (6735): 466–70. doi:10.1038/20933. PMID 10365958. 
  18. ^ a b c Hage SR, Jürgens U, Ehret G (June 2006). "Audio-vocal interaction in the pontine brainstem during self-initiated vocalization in the squirrel monkey". Eur. J. Neurosci. 23 (12): 3297–308. doi:10.1111/j.1460-9568.2006.04835.x. PMID 16820019. 
  19. ^ Amazi DK, Garber SR (December 1982). "The Lombard sign as a function of age and task". J Speech Hear Res 25 (4): 581–5. PMID 7162159. 
  20. ^ Jürgens U (January 2009). "The neural control of vocalization in mammals: a review". J Voice 23 (1): 1–10. doi:10.1016/j.jvoice.2007.07.005. PMID 18207362. 
  21. ^ a b Tonkinson S (March 1994). "The Lombard effect in choral singing". J Voice 8 (1): 24–9. doi:10.1016/S0892-1997(05)80316-9. PMID 8167784. 
  22. ^ Johnson CI, Pick HL, Garber SR, Siegel GM (June 1978). "Intensity of guitar playing as a function of auditory feedback". J. Acoust. Soc. Am. 63 (6): 1930. doi:10.1121/1.381900. PMID 681625. 
  23. ^ Brumm H., H; Slabbekoorn H. (2005). "Acoustic communication in noise". In: Advances in the Study of Behavior. Advances in the Study of Behavior 35: 151–209. doi:10.1016/S0065-3454(05)35004-2. ISBN 978-0-12-004535-8. 
  24. ^ Nonaka S, Takahashi R, Enomoto K, Katada A, Unno T (December 1997). "Lombard reflex during PAG-induced vocalization in decerebrate cats". Neurosci. Res. 29 (4): 283–9. doi:10.1016/S0168-0102(97)00097-7. PMID 9527619. 
  25. ^ Brumm B, Schmidt R, Schrader L (2009). "Noise-dependent vocal plasticity in domestic fowl". Animal Behaviour 78 (3): 741–6. doi:10.1016/j.anbehav.2009.07.004. 
  26. ^ Brumm H, Voss K, Köllmer I, Todt D (January 2004). "Acoustic communication in noise: regulation of call characteristics in a New World monkey". J. Exp. Biol. 207 (Pt 3): 443–8. doi:10.1242/jeb.00768. PMID 14691092. 
  27. ^ Egnor SE, Hauser MD (December 2006). "Noise-induced vocal modulation in cotton-top tamarins (Saguinus oedipus)". Am. J. Primatol. 68 (12): 1183–90. doi:10.1002/ajp.20317. PMID 17096420. 
  28. ^ Potash LM (1972). "Noise-induced changes in calls of the Japanese quail". Psychonomic Science 26: 252–4. doi:10.3758/bf03328608. 
  29. ^ Cynx J, Lewis R, Tavel B, Tse H (July 1998). "Amplitude regulation of vocalizations in noise by a songbird, Taeniopygia guttata". Anim Behav 56 (1): 107–13. doi:10.1006/anbe.1998.0746. PMID 9710467.