When speaking to infants, adults often produce speech that differs systematically from that directed to other adults. To quantify the acoustic properties of this speech style across a wide variety of languages and cultures, we extracted results from empirical studies on the acoustic features of infant-directed speech. We analysed data from 88 unique studies (734 effect sizes) on the following five acoustic parameters that have been systematically examined in the literature: fundamental frequency (f0), f0 variability, vowel space area, articulation rate and vowel duration. Moderator analyses were conducted in hierarchical Bayesian robust regression models to examine how these features change with infant age and differ across languages, experimental tasks and recording environments. The moderator analyses indicated that f0, articulation rate and vowel duration became more similar to adult-directed speech over time, whereas f0 variability and vowel space area exhibited stability throughout development. These results point the way for future research to disentangle different accounts of the functions and learnability of infant-directed speech by conducting theory-driven comparisons among different languages and using computational models to formulate testable predictions.
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The analysis and visualization code and a reproducible R Markdown manuscript are available and permanently archived in the following open repository: https://osf.io/hc7me/.
Fernald, A. Intonation and communicative intent in mothers’ speech to infants: is the melody the message? Child Dev. https://doi.org/10.2307/1130938 (1989).
Fernald, A. et al. A cross-language study of prosodic modifications in mothers’ and fathers’ speech to preverbal infants. J. Child Lang. 16, 477–501 (1989).
Stern, D. N., Spieker, S., Barnett, R. & MacKain, K. The prosody of maternal speech: infant age and context related changes. J. Child Lang. 10, 1–15 (1983).
Hilton, C. B. et al. Acoustic regularities in infant-directed speech and song across cultures. Nat. Hum. Behav. https://doi.org/10.1038/s41562-022-01410-x (2022).
Golinkoff, R. M., Can, D. D., Soderstrom, M. & Hirsh-Pasek, K. Baby talk to me: the social context of infant-directed speech and its effects on early language acquisition. Curr. Dir. Psychol. Sci. 24, 339–344 (2015).
Bryant, G. A. & Barrett, H. C. Recognizing intentions in infant-directed speech: evidence for universals. Psychol. Sci. 18, 746–751 (2007).
Fernald, A. Meaningful melodies in mothers’ speech to infants. in Nonverbal Vocal Communication: Comparative and Developmental Approaches (eds Papousek, H., Jürgens, U. & Papoušek, M.) 262–282 (Cambridge Univ. Press, 1992).
Owren, M. J. & Rendall, D. Sound on the rebound: bringing form and function back to the forefront in understanding nonhuman primate vocal signaling. Evol. Anthropol. 10, 58–71 (2001).
Kitamura, C. & Lam, C. Age‐specific preferences for infant‐directed affective intent. Infancy 14, 77–100 (2009).
Lam, C. & Kitamura, C. Developmental trends in infant preferences for affective intent in mothers’ speech. In Proc. 11th Australian International Conference on Speech Science & Technology (eds Warren, P. & Watson, C. I.). 100–105 (2006).
Kitamura, C. & Notley, A. The shift in infant preferences for vowel duration and pitch contour between 6 and 10 months of age. Dev. Sci. 12, 706–714 (2009).
McRoberts, G. W., McDonough, C. & Lakusta, L. The role of verbal repetition in the development of infant speech preferences from 4 to 14 months of age. Infancy 14, 162–194 (2009).
Panneton, R., Kitamura, C., Mattock, K. & Burnham, D. Slow speech enhances younger but not older infants’ perception of vocal emotion. Res. Hum. Dev. 3, 7–19 (2006).
Kalashnikova, M. & Burnham, D. Infant-directed speech from seven to nineteen months has similar acoustic properties but different functions. J. Child Lang. 45, 1035–1053 (2018).
Kuhl, P. K. et al. Cross-language analysis of phonetic units in language addressed to infants. Science 277, 684–686 (1997).
Liu, H., Kuhl, P. K. & Tsao, F. An association between mothers’ speech clarity and infants’ speech discrimination skills. Dev. Sci. 6, F1–F10 (2003).
Hartman, K. M., Ratner, N. B. & Newman, R. S. Infant-directed speech (IDS) vowel clarity and child language outcomes. J. Child Lang. 44, 1140–1162 (2017).
Peter, V., Kalashnikova, M., Santos, A. & Burnham, D. Mature neural responses to infant-directed speech but not adult-directed speech in pre-verbal infants. Sci. Rep. 6, 34273 (2016).
Song, Demuth, K. & Morgan, J. Effects of the acoustic properties of infant-directed speech on infant word recognition. J. Acoust. Soc. Am. 128, 389–400 (2010).
Cristia, A. & Seidl, A. The hyperarticulation hypothesis of infant-directed speech. J. Child Lang. 41, 913–934 (2014).
Martin, A. et al. Mothers speak less clearly to infants than to adults: a comprehensive test of the hyperarticulation hypothesis. Psychol. Sci. 26, 341–347 (2015).
McMurray, B., Kovack-Lesh, K. A., Goodwin, D. & McEchron, W. Infant directed speech and the development of speech perception: enhancing development or an unintended consequence? Cognition 129, 362–378 (2013).
Miyazawa, K., Shinya, T., Martin, A., Kikuchi, H. & Mazuka, R. Vowels in infant-directed speech: more breathy and more variable, but not clearer. Cognition 166, 84–93 (2017).
Rosslund, A., Mayor, J., Óturai, G. & Kartushina, N. Parents’ hyper-pitch and vowel category compactness in infant-directed speech are associated with 18-month-old toddlers’ expressive vocabulary. Preprint at PsyArXiv https://doi.org/10.31234/osf.io/wrku5 (2021).
Eaves, B. S., Feldman, N. H., Griffiths, T. L. & Shafto, P. Infant-directed speech is consistent with teaching. Psychol. Rev. 123, 758–771 (2016).
Perry, L. K., Samuelson, L. K., Malloy, L. M. & Schiffer, R. N. Learn locally, think globally: exemplar variability supports higher-order generalization and word learning. Psychol. Sci. 21, 1894–1902 (2010).
Rost, G. C. & McMurray, B. Speaker variability augments phonological processing in early word learning. Dev. Sci. 12, 339–349 (2009).
Rost, G. C. & McMurray, B. Finding the signal by adding noise: the role of noncontrastive phonetic variability in early word learning. Infancy 15, 608–635 (2010).
Goldstein, M. H. & Schwade, J. A. Social feedback to infants’ babbling facilitates rapid phonological learning. Psychol. Sci. 19, 515–523 (2008).
Ko, E.-S., Seidl, A., Cristia, A., Reimchen, M. & Soderstrom, M. Entrainment of prosody in the interaction of mothers with their young children. J. Child Lang. 43, 284–309 (2016).
Murray, L. & Trevarthen, C. The infant’s role in mother–infant communications. J. Child Lang. 13, 15–29 (1986).
Nguyen, V., Versyp, O., Cox, C. M. M. & Fusaroli, R. A systematic review and Bayesian meta-analysis of the development of turn taking in adult–child vocal interactions. Child Dev. https://doi.org/10.1111/cdev.13754 (2022).
Warlaumont, A. S., Richards, J. A., Gilkerson, J. & Oller, D. K. A social feedback loop for speech development and its reduction in autism. Psychol. Sci. 25, 1314–1324 (2014).
Cooper, R. P. & Aslin, R. N. Preference for infant‐directed speech in the first month after birth. Child Dev. 61, 1584–1595 (1990).
Fernald, A. & Simon, T. Expanded intonation contours in mothers’ speech to newborns. Dev. Psychol. 20, 104–113 (1984).
ManyBabies Consortium. Quantifying sources of variability in infancy research using the infant-directed-speech preference. Adv. Methods Pract. Psychol. Sci. 3, 24–52 (2020).
Pegg, J. E., Werker, J. F. & McLeod, P. J. Preference for infant-directed over adult-directed speech: evidence from 7-week-old infants. Infant Behav. Dev. 15, 325–345 (1992).
Werker, J. F. & McLeod, P. J. Infant preference for both male and female infant-directed talk: a developmental study of attentional and affective responsiveness. Can. J. Psychol. 43, 230–246 (1989).
Fernald, A. & Kuhl, P. Acoustic determinants of infant preference for motherese speech. Infant Behav. Dev. 10, 279–293 (1987).
Bainbridge, C. M. et al. Infants relax in response to unfamiliar foreign lullabies. Nat. Hum. Behav. 5, 256–264 (2021).
Tsuji, S. et al. MetaLab: a repository for meta-analyses on language development, and more. In Proc. Interspeech 2017 2038–2039 (International Speech Communication Association, 2017).
Dunst, C., Gorman, E. & Hamby, D. Preference for infant-directed speech in preverbal young children. Cent. Early Lit. Learn. 5, 1–13 (2012).
Hayashi, A., Tamekawa, Y. & Kiritani, S. Developmental change in auditory preferences for speech stimuli in Japanese infants. J. Speech Lang. Hear. Res. 44, 1189–1200 (2001).
Newman, R. S. & Hussain, I. Changes in preference for infant‐directed speech in low and moderate noise by 4.5‐ to 13‐month‐olds. Infancy 10, 61–76 (2006).
Kitamura, C. & Burnham, D. Acoustic and affective qualities of IDS in English. In Proc. 5th International Conference on Spoken Language Processing 0909 (International Speech Communication Association, 1998).
Singh, L., Morgan, J. L. & Best, C. T. Infants’ listening preferences: baby talk or happy talk? Infancy 3, 365–394 (2002).
Fernald, A. & Mazzie, C. Prosody and focus in speech to infants and adults. Dev. Psychol. 27, 209–221 (1991).
Segal, J. & Newman, R. S. Infant preferences for structural and prosodic properties of infant‐directed speech in the second year of life. Infancy 20, 339–351 (2015).
Ferguson, C. A. Baby talk in six languages. Am. Anthropol. 66, 103–114 (1964).
Casillas, M., Brown, P. & Levinson, S. C. Early language experience in a Tseltal Mayan village. Child Dev. 91, 1819–1835 (2020).
Cristia, A., Dupoux, E., Gurven, M. & Stieglitz, J. Child‐directed speech is infrequent in a forager–farmer population: a time allocation study. Child Dev. 90, 759–773 (2019).
Shneidman, L. A. & Goldin‐Meadow, S. Language input and acquisition in a Mayan village: how important is directed speech? Dev. Sci. 15, 659–673 (2012).
Bryant, G. A. Vocal communication across cultures: theoretical and methodological issues. Phil. Trans. R. Soc. B 377, 20200387 (2022).
Grieser, D. L. & Kuhl, P. K. Maternal speech to infants in a tonal language: support for universal prosodic features in motherese. Dev. Psychol. 24, 14–20 (1988).
Papoušek, M., Papoušek, H. & Symmes, D. The meanings of melodies in motherese in tone and stress languages. Infant Behav. Dev. 14, 415–440 (1991).
Räsänen, O., Seshadri, S., Lavechin, M., Cristia, A. & Casillas, M. An open-source tool for automatic measurement of phoneme, syllable, and word counts from child-centered daylong recordings. Behav. Res. Methods 53, 818–835 (2021).
Xu, D., Yapanel, U. & Gray, S. Reliability of the LENA Language Environment Analysis System in Young Children’s Natural Home Environment (LENA Foundation, 2009).
MacWhinney, B. The CHILDES Project: Tools for Analyzing Talk Vol. 2 (Psychology Press, 2014).
Floccia, C. et al. British English infants segment words only with exaggerated infant-directed speech stimuli. Cognition 148, 1–9 (2016).
Shute, B. & Wheldall, K. Fundamental frequency and temporal modifications in the speech of British fathers to their children. Educ. Psychol. 19, 221–233 (1999).
Haspelmath, M. The typological database of the World Atlas of Language Structures. in The Use of Databases in Cross-Linguistic Studies (eds Everaert M., Musgrave S. & Dimitriadis A.) 283–300 (De Gruyter Mouton, 2009).
Christiansen, M. H., Kallens, P. C. & Trecca, F. Towards a comparative approach to language acquisition. Curr. Dir. Psychol. Sci. https://doi.org/10.1177/09637214211049229 (2022).
Deffner, D., Rohrer, J. M. & McElreath, R. A causal framework for cross-cultural generalizability. Preprint at PsyArXiv https://doi.org/10.31234/osf.io/fqukp (2021).
Trecca, F., Tylén, K., Højen, A. & Christiansen, M. H. Danish as a window onto language processing and learning. Lang. Learn. 71, 799–833 (2021).
Nielsen, M., Haun, D., Kärtner, J. & Legare, C. H. The persistent sampling bias in developmental psychology: a call to action. J. Exp. Child Psychol. 162, 31–38 (2017).
Amano, S., Nakatani, T. & Kondo, T. Fundamental frequency of infants’ and parents’ utterances in longitudinal recordings. J. Acoust. Soc. Am. 119, 1636–1647 (2006).
Gergely, A., Faragó, T., Galambos, Á. & Topál, J. Differential effects of speech situations on mothers’ and fathers’ infant-directed and dog-directed speech: an acoustic analysis. Sci. Rep. 7, 1–10 (2017).
Han, M., De Jong, N. & Kager, R. Pitch properties of infant-directed speech specific to word-learning contexts: a cross-linguistic investigation of Mandarin Chinese and Dutch. J. Child Lang. 47, 85–111 (2020).
Niwano, K. & Sugai, K. Intonation contour of Japanese maternal infant-directed speech and infant vocal response. Jpn. J. Spec. Educ. 39, 59–68 (2002).
Vosoughi, S. & Roy, D. K. A longitudinal study of prosodic exaggeration in child-directed speech. In Proc. Speech Prosody 6th International Conference (Speech Prosody Special Interest Group, 2012); http://hdl.handle.net/1721.1/80790
Benders, T. Mommy is only happy! Dutch mothers’ realisation of speech sounds in infant-directed speech expresses emotion, not didactic intent. Infant Behav. Dev. 36, 847–862 (2013).
Kondaurova, M. V., Bergeson, T. R. & Xu, H. Age‐related changes in prosodic features of maternal speech to prelingually deaf infants with cochlear implants. Infancy 18, 825–848 (2013).
Kondaurova, M. V. & Bergeson, T. R. The effects of age and infant hearing status on maternal use of prosodic cues for clause boundaries in speech. J. Speech Lang. Hear. Res. 54, 740–754 (2011).
Lee, C. S., Kitamura, C., Burnham, D. & McAngus Todd, N. P. On the rhythm of infant- versus adult-directed speech in Australian English. J. Acoust. Soc. Am. 136, 357–365 (2014).
Narayan, C. R. & McDermott, L. C. Speech rate and pitch characteristics of infant-directed speech: longitudinal and cross-linguistic observations. J. Acoust. Soc. Am. 139, 1272–1281 (2016).
Raneri, D. P. Infant-Directed Speech: Maternal Pitch Variability, Rate of Speech, and Child Language Outcomes. Doctoral dissertation, Univ. Maryland (2015).
Knoll, M. A. & Costall, A. Characterising F (0) contour shape in infant- and foreigner-directed speech. Speech Commun. 66, 231–243 (2015).
Cristià, A. Phonetic enhancement of sibilants in infant-directed speech. J. Acoust. Soc. Am. 128, 424–434 (2010).
Liljencrants, J. & Lindblom, B. Numerical simulation of vowel quality systems: the role of perceptual contrast. Language https://doi.org/10.2307/411991 (1972).
Burnham, E. B. et al. Phonetic modification of vowel space in storybook speech to infants up to 2 years of age. J. Speech Lang. Hear. Res. 58, 241–253 (2015).
Hartman, K. M. Patterns and Possible Influences of Maternal Vowel Clarification on Child Language Development. Doctoral dissertation, Univ. Maryland (2013).
Lovcevic, I., Kalashnikova, M. & Burnham, D. Acoustic features of infant-directed speech to infants with hearing loss. J. Acoust. Soc. Am. 148, 3399–3416 (2020).
Weirich, M. & Simpson, A. Effects of gender, parental role, and time on infant- and adult-directed read and spontaneous speech. J. Speech Lang. Hear. Res. 62, 4001–4014 (2019).
Wieland, E. A., Burnham, E. B., Kondaurova, M., Bergeson, T. R. & Dilley, L. C. Vowel space characteristics of speech directed to children with and without hearing loss. J. Speech Lang. Hear. Res. 58, 254–267 (2015).
Dodane, C. & Al-Tamimi, J. An Acoustic Comparison of Vowel Systems in Adult-Directed-Speech and Child-Directed-Speech: Evidence from French, English & Japanese (Newcastle Univ., 2007).
Rattanasone, N. X., Burnham, D. & Reilly, R. G. Tone and vowel enhancement in Cantonese infant-directed speech at 3, 6, 9, and 12 months of age. J. Phon. 41, 332–343 (2013).
Huettig, F. & Guerra, E. Effects of speech rate, preview time of visual context, and participant instructions reveal strong limits on prediction in language processing. Brain Res. 1706, 196–208 (2019).
Gleitman, L. R., Newport, E. L. & Gleitman, H. The current status of the motherese hypothesis. J. Child Lang. 11, 43–79 (1984).
Seidl, A. & Cristià, A. Developmental changes in the weighting of prosodic cues. Dev. Sci. 11, 596–606 (2008).
Soderstrom, M., Seidl, A., Nelson, D. G. K. & Jusczyk, P. W. The prosodic bootstrapping of phrases: evidence from prelinguistic infants. J. Mem. Lang. 49, 249–267 (2003).
Englund, K. T. & Behne, D. M. Infant directed speech in natural interaction—Norwegian vowel quantity and quality. J. Psycholinguist. Res. 34, 259–280 (2005).
Outters, V., Schreiner, M. S., Behne, T. & Mani, N. Maternal input and infants’ response to infant‐directed speech. Infancy 25, 478–499 (2020).
Steen, V. B. & Englund, N. Child-directed speech in a Norwegian kindergarten setting. Scand. J. Educ. Res. https://doi.org/10.1080/00313831.2021.1897873 (2021).
Laver, J. Principles of Phonetics (Cambridge Univ. Press, 1994).
Tsao, Y.-C., Weismer, G. & Iqbal, K. Interspeaker variation in habitual speaking rate: additional evidence. J. Speech Lang. Hear. Res. 49, 1156–1164 (2006).
Tsao, Y.-C., Weismer, G. & Iqbal, K. The effect of intertalker speech rate variation on acoustic vowel space. J. Acoust. Soc. Am. 119, 1074–1082 (2006).
Englund, K. T. Hypoarticulation in infant-directed speech. Appl. Psycholinguist. 39, 67–87 (2018).
Christiansen, M. H. & Chater, N. The now-or-never bottleneck: a fundamental constraint on language. Behav. Brain Sci. 39, E62 (2016).
Saffran, J. R. & Kirkham, N. Z. Infant statistical learning. Annu. Rev. Psychol. 69, 181–203 (2018).
Werker, J. F. & Tees, R. C. Influences on infant speech processing: toward a new synthesis. Annu. Rev. Psychol. 50, 509–535 (1999).
Fusaroli, R., Weed, E., Fein, D. & Naigles, L. Hearing me hearing you: reciprocal effects between child and parent language in autism and typical development. Cognition 183, 1–18 (2019).
Smith, N. A. & Trainor, L. J. Infant-directed speech is modulated by infant feedback. Infancy 13, 410–420 (2008).
Spinelli, M., Fasolo, M. & Mesman, J. Does prosody make the difference? A meta-analysis on relations between prosodic aspects of infant-directed speech and infant outcomes. Dev. Rev. 44, 1–18 (2017).
De Boer, B. & Kuhl, P. K. Investigating the role of infant-directed speech with a computer model. Acoust. Res. Lett. Online 4, 129–134 (2003).
McMurray, B., Aslin, R. N. & Toscano, J. C. Statistical learning of phonetic categories: insights from a computational approach. Dev. Sci. 12, 369–378 (2009).
Vallabha, G. K., McClelland, J. L., Pons, F., Werker, J. F. & Amano, S. Unsupervised learning of vowel categories from infant-directed speech. Proc. Natl Acad. Sci. USA 104, 13273–13278 (2007).
Kalashnikova, M., Carignan, C. & Burnham, D. The origins of babytalk: smiling, teaching or social convergence? R. Soc. Open Sci. 4, 170306 (2017).
Mikolajewicz, N. & Komarova, S. V. Meta-analytic methodology for basic research: a practical guide. Front. Physiol. 10, 203 (2019).
Song, F., Sheldon, T. A., Sutton, A. J., Abrams, K. R. & Jones, D. R. Methods for exploring heterogeneity in meta-analysis. Eval. Health Prof. 24, 126–151 (2001).
Ruppar, T. Meta-analysis: how to quantify and explain heterogeneity? Eur. J. Cardiovasc. Nurs. 19, 646–652 (2020).
Church, R., Bernhardt, B., Pichora-Fuller, K. & Shi, R. Infant-directed speech: final syllable lengthening and rate of speech. Can. Acoust. 33, 13–19 (2005).
Martin, A., Igarashi, Y., Jincho, N. & Mazuka, R. Utterances in infant-directed speech are shorter, not slower. Cognition 156, 52–59 (2016).
Gavin, N. I. et al. Perinatal depression: a systematic review of prevalence and incidence. Obstet. Gynecol. 106, 1071–1083 (2005).
Gelaye, B., Rondon, M. B., Araya, R. & Williams, M. A. Epidemiology of maternal depression, risk factors, and child outcomes in low-income and middle-income countries. Lancet Psychiatry 3, 973–982 (2016).
Kaplan, P. S., Bachorowski, J., Smoski, M. J. & Zinser, M. Role of clinical diagnosis and medication use in effects of maternal depression on infant‐directed speech. Infancy 2, 537–548 (2001).
Lam-Cassettari, C. & Kohlhoff, J. Effect of maternal depression on infant-directed speech to prelinguistic infants: implications for language development. PLoS ONE 15, e0236787 (2020).
Porritt, L. L., Zinser, M. C., Bachorowski, J.-A. & Kaplan, P. S. Depression diagnoses and fundamental frequency-based acoustic cues in maternal infant-directed speech. Lang. Learn. Dev. 10, 51–67 (2014).
Woolard, A. et al. Infant and child-directed speech used with infants and children at risk or diagnosed with autism spectrum disorder: a scoping review. Rev. J. Autism Dev. Disord. 9, 290–306 (2022).
Cychosz, M. et al. Vocal development in a large‐scale crosslinguistic corpus. Dev. Sci. https://doi.org/10.1111/desc.13090 (2021).
Le Franc, A. et al. The ACLEW DiViMe: an easy-to-use diarization tool. In Proc. Interspeech 2018 1383–1387 (International Speech Communication Association, 2018).
Adriaans, F. & Swingley, D. Distributional learning of vowel categories is supported by prosody in infant-directed speech. Proc. Annu. Meet. Cogn. Sci. Soc. 34, 72–77 (2012).
Ludusan, B., Mazuka, R. & Dupoux, E. Does infant‐directed speech help phonetic learning? A machine learning investigation. Cogn. Sci. 45, e12946 (2021).
Räsänen, O., Kakouros, S. & Soderstrom, M. Is infant-directed speech interesting because it is surprising? Linking properties of IDS to statistical learning and attention at the prosodic level. Cognition 178, 193–206 (2018).
Kidd, C., Piantadosi, S. T. & Aslin, R. N. The Goldilocks effect: human infants allocate attention to visual sequences that are neither too simple nor too complex. PLoS ONE 7, e36399 (2012).
Kidd, C., Piantadosi, S. T. & Aslin, R. N. The Goldilocks effect in infant auditory attention. Child Dev. 85, 1795–1804 (2014).
Lam, C. & Kitamura, C. Maternal interactions with a hearing and hearing-impaired twin: similarities and differences in speech input, interaction quality, and word production. J. Speech Lang. Hear. Res. 53, 543–555 (2010).
Lam, C. & Kitamura, C. Mommy, speak clearly: induced hearing loss shapes vowel hyperarticulation. Dev. Sci. 15, 212–221 (2012).
Page, M. J. et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. Int. J. Surg. 88, 105918 (2021).
Aria, M. & Cuccurullo, C. bibliometrix: an R-tool for comprehensive science mapping analysis. J. Informetr. 11, 959–975 (2017).
Morris, S. B. Distribution of the standardized mean change effect size for meta‐analysis on repeated measures. Br. J. Math. Stat. Psychol. 53, 17–29 (2000).
Parola, A., Simonsen, A., Bliksted, V. & Fusaroli, R. Voice patterns in schizophrenia: a systematic review and Bayesian meta-analysis. Schizophr. Res. 216, 24–40 (2020).
Hedges, L. V. Distribution theory for Glass’s estimator of effect size and related estimators. J. Educ. Stat. 6, 107–128 (1981).
Lüdecke, D. esc: Effect size computation for meta analysis. R package version 05 (2019).
Rohatgi, A. WebPlotDigitizer User Manual Version 3.4 (2014).
Van Buuren, S. & Groothuis-Oudshoorn, K. mice: multivariate imputation by chained equations in R. J. Stat. Softw. 45, 1–67 (2011).
Hedges, L. V. & Olkin, I. Statistical Methods for Meta-analysis (Academic Press, 1985).
Raudenbush, S. W. & Bryk, A. S. Empirical Bayes meta-analysis. J. Educ. Stat. 10, 75–98 (1985).
Fernández-Castilla, B. et al. The application of meta-analytic (multi-level) models with multiple random effects: a systematic review. Behav. Res. Methods 52, 2031–2052 (2020).
Hedges, L. V. & Vevea, J. L. Fixed- and random-effects models in meta-analysis. Psychol. Methods 3, 486–504 (1998).
Jylänki, P., Vanhatalo, J. & Vehtari, A. Robust Gaussian process regression with a Student-t likelihood. J. Mach. Learn. Res. 12, 3227–3257 (2011).
Vehtari, A., Gelman, A. & Gabry, J. Practical Bayesian model evaluation using leave-one-out cross-validation and WAIC. Stat. Comput. 27, 1413–1432 (2017).
Yao, Y., Vehtari, A., Simpson, D. & Gelman, A. Using stacking to average Bayesian predictive distributions (with discussion). Bayesian Anal. 13, 917–1007 (2018).
R Core Team. R: A Language and Environment for Statistical Computing (R Foundation for Statistical Computing, 2020).
Bürkner, P.-C. brms: an R package for Bayesian multilevel models using Stan. J. Stat. Softw. 80, 1–28 (2017).
Carpenter, B. et al. Stan: a probabilistic programming language. J. Stat. Softw. 76, 1–32 (2017).
RStudio: Integrated Development for R v.1.4 (RStudio, PBC, 2020).
Lemoine, N. P. Moving beyond noninformative priors: why and how to choose weakly informative priors in Bayesian analyses. Oikos 128, 912–928 (2019).
Gelman, A., Simpson, D. & Betancourt, M. The prior can often only be understood in the context of the likelihood. Entropy 19, 555 (2017).
Mathur, M. B. & VanderWeele, T. J. Sensitivity analysis for publication bias in meta‐analyses. J. R. Stat. Soc. C 69, 1091–1119 (2020).
Fusaroli, R., Lambrechts, A., Bang, D., Bowler, D. M. & Gaigg, S. B. Is voice a marker for autism spectrum disorder? A systematic review and meta‐analysis. Autism Res. 10, 384–407 (2017).
Jin, Z., Zhou, X. & He, J. Statistical methods for dealing with publication bias in meta‐analysis. Stat. Med. 34, 343–360 (2015).
McShane, B. B., Böckenholt, U. & Hansen, K. T. Adjusting for publication bias in meta-analysis: an evaluation of selection methods and some cautionary notes. Perspect. Psychol. Sci. 11, 730–749 (2016).
Pustejovsky, J. E. & Rodgers, M. A. Testing for funnel plot asymmetry of standardized mean differences. Res. Synth. Methods 10, 57–71 (2019).
R.F. has been a paid consultant for F. Hoffman La Roche on related but non-overlapping topics. This project has been supported by seed funding from the Interacting Minds Centre at Aarhus University, awarded to R.F. and E.F. All of the computation done for this project was performed on the UCloud interactive HPC system, which is managed by the eScience Center at the University of Southern Denmark. The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.
The authors declare no competing interests.
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A heatmap providing an overview of the effect size estimates for each of the acoustic variables and languages. Dark orange shading indicates a strong effect size value on the positive scale. Dark blue shading indicates a strong effect on the negative scale.
Data for the included languages and their sample sizes.
Data for the diagram of longitudinal studies.
Data on pitch.
Data on pitch variability.
Data on vowel space area.
Data on articulation rate.
Data on vowel duration.
Data for the heatmap visualization.
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Cox, C., Bergmann, C., Fowler, E. et al. A systematic review and Bayesian meta-analysis of the acoustic features of infant-directed speech. Nat Hum Behav 7, 114–133 (2023). https://doi.org/10.1038/s41562-022-01452-1
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