Acoustic regularities in infant-directed speech and song across cultures

Children and adults produce distinct technology- and human-directed speech

This study compares how English-speaking adults and children from the United States adapt their speech when talking to a real person and a smart speaker (Amazon Alexa) in a psycholinguistic experiment. Overall, participants produced more effortful speech when talking to a device (longer duration and higher pitch). These differences also varied by age: children produced even higher pitch in device-directed speech, suggesting a stronger expectation to be misunderstood by the system. In support of this, we see that after a staged recognition error by the device, children increased pitch even more. Furthermore, both adults and children displayed the same degree of variation in their responses for whether "Alexa seems like a real person or not", further indicating that children's conceptualization of the system's competence shaped their register adjustments, rather than an increased anthropomorphism response. This work speaks to models on the mechanisms underlying speech production, and human-computer interaction frameworks, providing support for routinized theories of spoken interaction with technology.

Maternal singing reduced pain indexes in 2-month-old infants and increased proximity during vaccinations

AIM

Immunisation is a global health priority, but methods of non-pharmacological pain relief are not widely used in routine clinical practice. In this study, we set out to investigate the effects of maternal singing during the routine vaccination of infants.

METHODS

We recruited 67 mother-infant pairs at Health Centres in the Aosta Region of Italy. Infants aged 2-4 months were randomly allocated to a singing intervention group or to a control group whose injections were administered following standard practice. Pre- and post-immunisation pain was blindly assessed using the Modified Behavioural Pain Scale, and mother-infant proximity indexes were assigned based on muted video-tracks.

RESULTS

When assessed for pain, the infants in the maternal singing group were assigned significantly lower movement indexes (p = 0.032) and marginally significantly lower cry indexes (p = 0.076). A higher frequency of mother-to-infant gaze (p < 0.005) was observed in the singing group dyads. Finally, the intervention group mothers' self-perceived ease in singing was correlated with their previous singing experience and with lower anxiety following the vaccination procedure (p < 0.05).

CONCLUSION

Maternal singing during immunisation procedures benefits both mothers and babies. The practice of singing is a biologically rooted and adaptive form of intuitive parental communication that should be encouraged, especially in at-risk populations.

Spectro-temporal acoustical markers differentiate speech from song across cultures

Humans produce two forms of cognitively complex vocalizations: speech and song. It is debated whether these differ based primarily on culturally specific, learned features, or if acoustical features can reliably distinguish them. We study the spectro-temporal modulation patterns of vocalizations produced by 369 people living in 21 urban, rural, and small-scale societies across six continents. Specific ranges of spectral and temporal modulations, overlapping within categories and across societies, significantly differentiate speech from song. Machine-learning classification shows that this effect is cross-culturally robust, vocalizations being reliably classified solely from their spectro-temporal features across all 21 societies. Listeners unfamiliar with the cultures classify these vocalizations using similar spectro-temporal cues as the machine learning algorithm. Finally, spectro-temporal features are better able to discriminate song from speech than a broad range of other acoustical variables, suggesting that spectro-temporal modulation-a key feature of auditory neuronal tuning-accounts for a fundamental difference between these categories.

Signatures of speech and song: "Universal" links despite cultural diversity

Equitable collaboration between culturally diverse scientists reveals that acoustic fingerprints of human speech and song share parallel relationships across the globe.

Globally, songs and instrumental melodies are slower and higher and use more stable pitches than speech: A Registered Report

Both music and language are found in all known human societies, yet no studies have compared similarities and differences between song, speech, and instrumental music on a global scale. In this Registered Report, we analyzed two global datasets: (i) 300 annotated audio recordings representing matched sets of traditional songs, recited lyrics, conversational speech, and instrumental melodies from our 75 coauthors speaking 55 languages; and (ii) 418 previously published adult-directed song and speech recordings from 209 individuals speaking 16 languages. Of our six preregistered predictions, five were strongly supported: Relative to speech, songs use (i) higher pitch, (ii) slower temporal rate, and (iii) more stable pitches, while both songs and speech used similar (iv) pitch interval size and (v) timbral brightness. Exploratory analyses suggest that features vary along a "musi-linguistic" continuum when including instrumental melodies and recited lyrics. Our study provides strong empirical evidence of cross-cultural regularities in music and speech.

Global musical diversity is largely independent of linguistic and genetic histories

Music is a universal yet diverse cultural trait transmitted between generations. The extent to which global musical diversity traces cultural and demographic history, however, is unresolved. Using a global musical dataset of 5242 songs from 719 societies, we identify five axes of musical diversity and show that music contains geographical and historical structures analogous to linguistic and genetic diversity. After creating a matched dataset of musical, genetic, and linguistic data spanning 121 societies containing 981 songs, 1296 individual genetic profiles, and 121 languages, we show that global musical similarities are only weakly and inconsistently related to linguistic or genetic histories, with some regional exceptions such as within Southeast Asia and sub-Saharan Africa. Our results suggest that global musical traditions are largely distinct from some non-musical aspects of human history.

Weighting of cues to categorization of song versus speech in tone-language and non-tone-language speakers

One of the most important auditory categorization tasks a listener faces is determining a sound's domain, a process which is a prerequisite for successful within-domain categorization tasks such as recognizing different speech sounds or musical tones. Speech and song are universal in human cultures: how do listeners categorize a sequence of words as belonging to one or the other of these domains? There is growing interest in the acoustic cues that distinguish speech and song, but it remains unclear whether there are cross-cultural differences in the evidence upon which listeners rely when making this fundamental perceptual categorization. Here we use the speech-to-song illusion, in which some spoken phrases perceptually transform into song when repeated, to investigate cues to this domain-level categorization in native speakers of tone languages (Mandarin and Cantonese speakers residing in the United Kingdom and China) and in native speakers of a non-tone language (English). We find that native tone-language and non-tone-language listeners largely agree on which spoken phrases sound like song after repetition, and we also find that the strength of this transformation is not significantly different across language backgrounds or countries of residence. Furthermore, we find a striking similarity in the cues upon which listeners rely when perceiving word sequences as singing versus speech, including small pitch intervals, flat within-syllable pitch contours, and steady beats. These findings support the view that there are certain widespread cross-cultural similarities in the mechanisms by which listeners judge if a word sequence is spoken or sung.

Commonality and variation in mental representations of music revealed by a cross-cultural comparison of rhythm priors in 15 countries

Music is present in every known society but varies from place to place. What, if anything, is universal to music cognition? We measured a signature of mental representations of rhythm in 39 participant groups in 15 countries, spanning urban societies and Indigenous populations. Listeners reproduced random 'seed' rhythms; their reproductions were fed back as the stimulus (as in the game of 'telephone'), such that their biases (the prior) could be estimated from the distribution of reproductions. Every tested group showed a sparse prior with peaks at integer-ratio rhythms. However, the importance of different integer ratios varied across groups, often reflecting local musical practices. Our results suggest a common feature of music cognition: discrete rhythm 'categories' at small-integer ratios. These discrete representations plausibly stabilize musical systems in the face of cultural transmission but interact with culture-specific traditions to yield the diversity that is evident when mental representations are probed across many cultures.

Evidence for Infant-directed Speech Preference Is Consistent Across Large-scale, Multi-site Replication and Meta-analysis

There is substantial evidence that infants prefer infant-directed speech (IDS) to adult-directed speech (ADS). The strongest evidence for this claim has come from two large-scale investigations: i) a community-augmented meta-analysis of published behavioral studies and ii) a large-scale multi-lab replication study. In this paper, we aim to improve our understanding of the IDS preference and its boundary conditions by combining and comparing these two data sources across key population and design characteristics of the underlying studies. Our analyses reveal that both the meta-analysis and multi-lab replication show moderate effect sizes (d ≈ 0.35 for each estimate) and that both of these effects persist when relevant study-level moderators are added to the models (i.e., experimental methods, infant ages, and native languages). However, while the overall effect size estimates were similar, the two sources diverged in the effects of key moderators: both infant age and experimental method predicted IDS preference in the multi-lab replication study, but showed no effect in the meta-analysis. These results demonstrate that the IDS preference generalizes across a variety of experimental conditions and sampling characteristics, while simultaneously identifying key differences in the empirical picture offered by each source individually and pinpointing areas where substantial uncertainty remains about the influence of theoretically central moderators on IDS preference. Overall, our results show how meta-analyses and multi-lab replications can be used in tandem to understand the robustness and generalizability of developmental phenomena.

First They Scream, Then They Laugh: The Cognitive Intersections of Humor and Fear

On the surface, fear and humor seem like polar opposite states of mind, yet throughout our lives they continually interact. In this paper, we synthesize neurobiological, psychological, and evolutionary research on fear and humor, arguing that the two are deeply connected. The evolutionary origins of humor reside in play, a medium through which animals benignly explore situations and practice strategies, such as fight or flight, which would normally be accompanied by fear. Cognitively, humor retains the structure of play. Adopting a view of humor as requiring two appraisals, a violation appraisal and a benign appraisal, we describe how fear-inducing stimuli can be rendered benignly humorous through contextual cues, psychological distance, reframing, and cognitive reappraisal. The antagonistic relationship between humor and fear in terms of their neurochemistry and physiological effects in turn makes humor ideal for managing fear in many circumstances. We review five real-world examples of humor and fear intersecting, presenting new data in support of our account along the way. Finally, we discuss the possible therapeutic relevance of the deep connection between humor and fear.

The role of acoustic features of maternal infant-directed singing in enhancing infant sensorimotor, language and socioemotional development

The quality of infant-directed speech (IDS) and infant-directed singing (IDSi) are considered vital to children, but empirical studies on protomusical qualities of the IDSi influencing infant development are rare. The current prospective study examines the role of IDSi acoustic features, such as pitch variability, shape and movement, and vocal amplitude vibration, timbre, and resonance, in associating with infant sensorimotor, language, and socioemotional development at six and 18 months. The sample consists of 236 Palestinian mothers from Gaza Strip singing to their six-month-olds a song by their own choice. Maternal IDSi was recorded and analyzed by the OpenSMILE- tool to depict main acoustic features of pitch frequencies, variations, and contours, vocal intensity, resonance formants, and power. The results are based on completed 219 maternal IDSi. Mothers reported about their infants' sensorimotor, language-vocalization, and socioemotional skills at six months, and psychologists tested these skills by Bayley Scales for Infant Development at 18 months. Results show that maternal IDSi characterized by wide pitch variability and rich and high vocal amplitude and vibration were associated with infants' optimal sensorimotor, language vocalization, and socioemotional skills at six months, and rich and high vocal amplitude and vibration predicted these optimal developmental skills also at 18 months. High resonance and rhythmicity formants were associated with optimal language and vocalization skills at six months. To conclude, the IDSi is considered important in enhancing newborn and risk infants' wellbeing, and the current findings argue that favorable acoustic singing qualities are crucial for optimal multidomain development across infancy.

Parallelisms and deviations: two fundamentals of an aesthetics of poetic diction

Poetic diction routinely involves two complementary classes of features: (i) parallelisms, i.e. repetitive patterns (rhyme, metre, alliteration, etc.) that enhance the predictability of upcoming words, and (ii) poetic deviations that challenge standard expectations/predictions regarding regular word form and order. The present study investigated how these two prediction-modulating fundamentals of poetic diction affect the cognitive processing and aesthetic evaluation of poems, humoristic couplets and proverbs. We developed quantitative measures of these two groups of text features. Across the three text genres, higher deviation scores reduced both comprehensibility and aesthetic liking whereas higher parallelism scores enhanced these. The positive effects of parallelism are significantly stronger than the concurrent negative effects of the features of deviation. These results are in accord with the hypothesis that art reception involves an interplay of prediction errors and prediction error minimization, with the latter paving the way for processing fluency and aesthetic liking. This article is part of the theme issue 'Art, aesthetics and predictive processing: theoretical and empirical perspectives'.

Child-Directed Speech in Noise: Testing Signal- and Code-Based Phonetic Enhancement

PURPOSE

Talkers adapt their speech according to the demands of their listeners and the communicative context, enhancing the properties of the signal (pitch, intensity) and/or properties of the code (enhancement of phonemic contrasts). This study asked how mothers adapt their child-directed speech (CDS) in ways that might serve the immediate goals of increasing intelligibility, as well as long-term goals of supporting speech and language development in their children.

METHOD

Mothers (N = 28) participated in a real-time interactive speech production/perception paradigm, in which mothers instructed their young (3- to 5-year-old) children, or an adult listener, to select the picture corresponding to a target word. The task was performed at low and high levels (56 vs. 75 dB SPL) of background noise to examine the Lombard effects of decreased audibility on speech production.

RESULTS

Acoustic-phonetic analyses of CDS and adult-directed speech (ADS) productions of target words and carrier phrase (e.g., "Find pig") revealed that mothers significantly enhanced the mean pitch, pitch variability, and intensity of target words in CDS, particularly at higher background noise levels and for younger children. Mothers produce CDS with a higher signal-to-noise ratio than ADS. However, limited evidence was found for phonetic enhancement of the segmental properties of speech. Although increased category separation was found in the voice onset time of stop consonants, decreased vowel category separation (an anti-enhancement effect) was observed in CDS.

CONCLUSIONS

Mothers readily enhance the suprasegmental signal properties of their speech in CDS, but not the acoustic-phonetic properties of phonemes. This study fails to provide evidence of phonetic enhancement in preschool children in a dyadic communication task under noisy listening conditions.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24645423.

Does Electrophysiological Maturation Shape Language Acquisition?

Infants master temporal patterns of their native language at a developmental trajectory from slow to fast: Shortly after birth, they recognize the slow acoustic modulations specific to their native language before tuning into faster language-specific patterns between 6 and 12 months of age. We propose here that this trajectory is constrained by neuronal maturation-in particular, the gradual emergence of high-frequency neural oscillations in the infant electroencephalogram. Infants' initial focus on slow prosodic modulations is consistent with the prenatal availability of slow electrophysiological activity (i.e., theta- and delta-band oscillations). Our proposal is consistent with the temporal patterns of infant-directed speech, which initially amplifies slow modulations, approaching the faster modulation range of adult-directed speech only as infants' language has advanced sufficiently. Moreover, our proposal agrees with evidence from premature infants showing maturational age is a stronger predictor of language development than ex utero exposure to speech, indicating that premature infants cannot exploit their earlier availability of speech because of electrophysiological constraints. In sum, we provide a new perspective on language acquisition emphasizing neuronal development as a critical driving force of infants' language development.

Music production and its role in coalition signaling during foraging contexts in a hunter-gatherer society

Music is a cultural activity universally present in all human societies. Several hypotheses have been formulated to understand the possible origins of music and the reasons for its emergence. Here, we test two hypotheses: (1) the coalition signaling hypothesis which posits that music could have emerged as a tool to signal cooperative intent and signal strength of alliances and (2) music as a strategy to deter potential predators. In addition, we further explore the link between tactile cues and the propensity of mothers to sing toward infants. For this, we investigated the singing behaviors of hunter-gatherer mothers during daily foraging trips among the Mbendjele BaYaka in the Republic of the Congo. Although singing is a significant component of their daily activities, such as when walking in the forest or collecting food sources, studies on human music production in hunter-gatherer societies are mostly conducted during their ritual ceremonies. In this study, we collected foraging and singing behavioral data of mothers by using focal follows of five BaYaka women during their foraging trips in the forest. In accordance with our predictions for the coalition signaling hypothesis, women were more likely to sing when present in large groups, especially when group members were less familiar. However, predictions of the predation deterrence hypothesis were not supported as the interaction between group size and distance from the village did not have a significant effect on the likelihood of singing. The latter may be due to limited variation in predation risk in the foraging areas, because of the intense bush meat trade, and hence, future studies should include foraging areas with higher densities of wild animals. Lastly, we found that mothers were more likely to sing when they were carrying infants compared to when infants were close, but carried by others, supporting the prediction that touch plays an important prerequisite role in musical interaction between the mother and child. Our study provides important insight into the role of music as a tool in displaying the intent between or within groups to strengthen potentially conflict-free alliances during joint foraging activities.

Parent coaching from 6 to 18 months improves child language outcomes through 30 months of age

Interventions focused on the home language environment have been shown to improve a number of child language outcomes in the first years of life. However, data on the longer-term effects of the intervention are still somewhat limited. The current study examines child vocabulary and complex speech outcomes (N = 59) during the year following completion of a parent-coaching intervention, which was previously found to increase the quantity of parent-child conversational turns and to improve child language outcomes through 18 months of age. Measures of parental language input, child speech output, and parent-child conversational turn-taking were manually coded from naturalistic home recordings (Language Environment Analysis System, LENA) at regular 4-month intervals when children were 6- to 24-months old. Child language skills were assessed using the MacArthur-Bates Communicative Development Inventory (CDI) at four time-points following the final intervention session (at 18, 24, 27, and 30 months). Vocabulary size and growth from 18 to 30 months was greater in the intervention group, even after accounting for differences in child language ability during the intervention period. The intervention group also scored higher on measures of speech length and grammatical complexity, and these effects were mediated by 18-month vocabulary. Intervention was associated with increased parent-child conversational turn-taking in home recordings at 14 months, and mediation analysis suggested that 14-month conversational turn-taking accounted for intervention-related differences in subsequent vocabulary. Together, the results suggest enduring, positive effects of parental language intervention and underscore the importance of interactive, conversational language experience during the first 2 years of life. RESEARCH HIGHLIGHTS: Parent coaching was provided as part of a home language intervention when children were 6-18 months of age. Naturalistic home language recordings showed increased parent-child conversational turn-taking in the intervention group at 14 months of age. Measures of productive vocabulary and complex speech indicated more advanced expressive language skills in the intervention group through 30 months of age, a full year after the final intervention session. Conversational turn-taking at 14 months predicted subsequent child vocabulary and accounted for differences in vocabulary size across the intervention and control groups.

Cross-cultural Perception of Musical Similarity Within and Between India and Japan

Cross-cultural perception of musical similarity is important for understanding musical diversity and universality. In this study we analyzed cross-cultural music similarity ratings on a global song sample from 110 participants (62 previously published from Japan, 48 newly collected from musicians and non-musicians from north and south India). Our pre-registered hypothesis that average Indian and Japanese ratings would be correlated was strongly supported (r = .80, p <.001). Exploratory analyses showed that ratings from experts in Hindustani music from the north and Carnatic music from the south showed the lowest correlations (r= .25). These analyses suggest that the correlations we found are likely due more to shared musical exposure than to innate universals of music perception.

Early social communication through music: State of the art and future perspectives

A growing body of research shows that the universal capacity for music perception and production emerges early in development. Possibly building on this predisposition, caregivers around the world often communicate with infants using songs or speech entailing song-like characteristics. This suggests that music might be one of the earliest developing and most accessible forms of interpersonal communication, providing a platform for studying early communicative behavior. However, little research has examined music in truly communicative contexts. The current work aims to facilitate the development of experimental approaches that rely on dynamic and naturalistic social interactions. We first review two longstanding lines of research that examine musical interactions by focusing either on the caregiver or the infant. These include defining the acoustic and non-acoustic features that characterize infant-directed (ID) music, as well as behavioral and neurophysiological research examining infants' processing of musical timing and pitch. Next, we review recent studies looking at early musical interactions holistically. This research focuses on how caregivers and infants interact using music to achieve co-regulation, mutual engagement, and increase affiliation and prosocial behavior. We conclude by discussing methodological, technological, and analytical advances that might empower a comprehensive study of musical communication in early childhood.

Universal interpretations of vocal music

Despite the variability of music across cultures, some types of human songs share acoustic characteristics. For example, dance songs tend to be loud and rhythmic, and lullabies tend to be quiet and melodious. Human perceptual sensitivity to the behavioral contexts of songs, based on these musical features, suggests that basic properties of music are mutually intelligible, independent of linguistic or cultural content. Whether these effects reflect universal interpretations of vocal music, however, is unclear because prior studies focus almost exclusively on English-speaking participants, a group that is not representative of humans. Here, we report shared intuitions concerning the behavioral contexts of unfamiliar songs produced in unfamiliar languages, in participants living in Internet-connected industrialized societies (n = 5,516 native speakers of 28 languages) or smaller-scale societies with limited access to global media (n = 116 native speakers of three non-English languages). Participants listened to songs randomly selected from a representative sample of human vocal music, originally used in four behavioral contexts, and rated the degree to which they believed the song was used for each context. Listeners in both industrialized and smaller-scale societies inferred the contexts of dance songs, lullabies, and healing songs, but not love songs. Within and across cohorts, inferences were mutually consistent. Further, increased linguistic or geographical proximity between listeners and singers only minimally increased the accuracy of the inferences. These results demonstrate that the behavioral contexts of three common forms of music are mutually intelligible cross-culturally and imply that musical diversity, shaped by cultural evolution, is nonetheless grounded in some universal perceptual phenomena.

Brief Report: Telehealth Music-Enhanced Reciprocal Imitation Training in Autism: A Single-Subject Feasibility Study of a Virtual Parent Coaching Intervention

PURPOSE

Telehealth delivery increases accessibility of parent-mediated interventions that teach parents skills and support autistic children's social communication. Reciprocal Imitation Training (RIT), an evidence-based Naturalistic Developmental Behavioral Intervention (NDBI) focused on imitation skills, a common difficulty in autism, holds promise for telehealth-based parent training. Imitation is also a core component of musical play during childhood and the affordances of musical play/song naturally shape parent-child interactions. We evaluate the feasibility of a music-based, telehealth adaptation of RIT-music-enhanced RIT (tele-meRIT)-as a novel format for coaching parents in NDBI strategies.

METHODS

This single-subject, multiple baseline design study included 4 autistic children (32-53 months old) and their mothers. Parent-child dyads were recorded during 10-min free play probes at baseline, weekly tele-meRIT sessions, and one-week and one-month follow-up. Probes were coded for parents' RIT implementation fidelity, parent vocal musicality, and children's rate of spontaneous imitation.

RESULTS

No parent demonstrated implementation fidelity during baseline. All parents increased their use of RIT strategies, met fidelity by the end of treatment, and maintained fidelity at follow-up. Parent vocal musicality also increased from baseline. Intervention did not consistently increase children's imitation skills. A post-intervention evaluation survey indicated high parent satisfaction with tele-meRIT and perceived benefits to their children's social and play skills more broadly.

CONCLUSION

Implementing tele-meRIT is feasible. Although tele-meRIT additionally involved coaching in incorporating rhythmicity and song into play interactions, parents achieved fidelity in the RIT principles, suggesting one avenue by which music can be integrated within evidence-based parent-mediated NDBIs.

Bottlenose dolphin mothers modify signature whistles in the presence of their own calves

Human caregivers interacting with children typically modify their speech in ways that promote attention, bonding, and language acquisition. Although this "motherese," or child-directed communication (CDC), occurs in a variety of human cultures, evidence among nonhuman species is very rare. We looked for its occurrence in a nonhuman mammalian species with long-term mother-offspring bonds that is capable of vocal production learning, the bottlenose dolphin (Tursiops truncatus). Dolphin signature whistles provide a unique opportunity to test for CDC in nonhuman animals, because we are able to quantify changes in the same vocalizations produced in the presence or absence of calves. We analyzed recordings made during brief catch-and-release events of wild bottlenose dolphins in waters near Sarasota Bay, Florida, United States, and found that females produced signature whistles with significantly higher maximum frequencies and wider frequency ranges when they were recorded with their own dependent calves vs. not with them. These differences align with the higher fundamental frequencies and wider pitch ranges seen in human CDC. Our results provide evidence in a nonhuman mammal for changes in the same vocalizations when produced in the presence vs. absence of offspring, and thus strongly support convergent evolution of motherese, or CDC, in bottlenose dolphins. CDC may function to enhance attention, bonding, and vocal learning in dolphin calves, as it does in human children. Our data add to the growing body of evidence that dolphins provide a powerful animal model for studying the evolution of vocal learning and language.

Introducing Meta-analysis in the Evaluation of Computational Models of Infant Language Development

Computational models of child language development can help us understand the cognitive underpinnings of the language learning process, which occurs along several linguistic levels at once (e.g., prosodic and phonological). However, in light of the replication crisis, modelers face the challenge of selecting representative and consolidated infant data. Thus, it is desirable to have evaluation methodologies that could account for robust empirical reference data, across multiple infant capabilities. Moreover, there is a need for practices that can compare developmental trajectories of infants to those of models as a function of language experience and development. The present study aims to take concrete steps to address these needs by introducing the concept of comparing models with large-scale cumulative empirical data from infants, as quantified by meta-analyses conducted across a large number of individual behavioral studies. We formalize the connection between measurable model and human behavior, and then present a conceptual framework for meta-analytic evaluation of computational models. We exemplify the meta-analytic model evaluation approach with two modeling experiments on infant-directed speech preference and native/non-native vowel discrimination.

Two-part vowel modifications in Child Directed Speech in Warlpiri may enhance child attention to speech and scaffold noun acquisition

Study 1 compared vowels in Child Directed Speech (CDS; child ages 25-46 months) to vowels in Adult Directed Speech (ADS) in natural conversation in the Australian Indigenous language Warlpiri, which has three vowels (/i/, /a/, /u). Study 2 compared the vowels of the child interlocutors from Study 1 to caregiver ADS and CDS. Study 1 indicates that Warlpiri CDS vowels are characterised by fronting, /a/-lowering, f _o -raising, and increased duration, but not vowel space expansion. Vowels in CDS nouns, however, show increased between-contrast differentiation and reduced within-contrast variation, similar to what has been reported for other languages. We argue that this two-part CDS modification process serves a dual purpose: Vowel space shifting induces IDS/CDS that sounds more child-like, which may enhance child attention to speech, while increased between-contrast differentiation and reduced within-contrast variation in nouns may serve didactic purposes by providing high-quality information about lexical specifications. Study 2 indicates that Warlpiri CDS vowels are more like child vowels, providing indirect evidence that aspects of CDS may serve non-linguistic purposes simultaneously with other aspects serving linguistic-didactic purposes. The studies have novel implications for the way CDS vowel modifications are considered and highlight the necessity of naturalistic data collection, novel analyses, and typological diversity.

Curiosity constructs communicative competence through social feedback loops

One of the most important challenges for a developing infant is learning how best to allocate their attention and forage for information in the midst of a great deal of novel stimulation. We propose that infants of altricial species solve this challenge by learning selectively from events that are contingent on their immature behavior, such as babbling. Such a contingency filter would focus attention and learning on the behavior of social partners, because social behavior reliably fits infants' sensitivity to contingency. In this way a contingent response by a caregiver to an immature behavior becomes a source of learnable information - feedback - to the infant. Social interactions with responsive caregivers afford infants opportunities to explore the impacts of their immature behavior on their environment, which facilitates the development of socially guided learning. Furthermore, contingent interactions are opportunities to make and test predictions about the efficacy of their social behaviors and those of others. In this chapter, we will use prelinguistic vocal learning to exemplify how infants use their developing vocal abilities to elicit learnable information about language from their social partners. Specifically, we review how caregivers' contingent responses to babbling create information that facilitates infant vocal learning and drives the development of communication. Infants play an active role in this process, as their developing predictions about the consequences of their actions serve to further refine their allocation of attention and drive increases in the maturity of their vocal behavior.

Universality, domain-specificity, and development of psychological responses to music

Humans can find music happy, sad, fearful, or spiritual. They can be soothed by it or urged to dance. Whether these psychological responses reflect cognitive adaptations that evolved expressly for responding to music is an ongoing topic of study. In this Review, we examine three features of music-related psychological responses that help to elucidate whether the underlying cognitive systems are specialized adaptations: universality, domain-specificity, and early expression. Focusing on emotional and behavioural responses, we find evidence that the relevant psychological mechanisms are universal and arise early in development. However, the existing evidence cannot establish that these mechanisms are domain-specific. To the contrary, many findings suggest that universal psychological responses to music reflect more general properties of emotion, auditory perception, and other human cognitive capacities that evolved for non-musical purposes. Cultural evolution, driven by the tinkering of musical performers, evidently crafts music to compellingly appeal to shared psychological mechanisms, resulting in both universal patterns (such as form-function associations) and culturally idiosyncratic styles.

Perceived rhythmic regularity is greater for song than speech: examining acoustic correlates of rhythmic regularity in speech and song

Rhythm is a key feature of music and language, but the way rhythm unfolds within each domain differs. Music induces perception of a beat, a regular repeating pulse spaced by roughly equal durations, whereas speech does not have the same isochronous framework. Although rhythmic regularity is a defining feature of music and language, it is difficult to derive acoustic indices of the differences in rhythmic regularity between domains. The current study examined whether participants could provide subjective ratings of rhythmic regularity for acoustically matched (syllable-, tempo-, and contour-matched) and acoustically unmatched (varying in tempo, syllable number, semantics, and contour) exemplars of speech and song. We used subjective ratings to index the presence or absence of an underlying beat and correlated ratings with stimulus features to identify acoustic metrics of regularity. Experiment 1 highlighted that ratings based on the term "rhythmic regularity" did not result in consistent definitions of regularity across participants, with opposite ratings for participants who adopted a beat-based definition (song greater than speech), a normal-prosody definition (speech greater than song), or an unclear definition (no difference). Experiment 2 defined rhythmic regularity as how easy it would be to tap or clap to the utterances. Participants rated song as easier to clap or tap to than speech for both acoustically matched and unmatched datasets. Subjective regularity ratings from Experiment 2 illustrated that stimuli with longer syllable durations and with less spectral flux were rated as more rhythmically regular across domains. Our findings demonstrate that rhythmic regularity distinguishes speech from song and several key acoustic features can be used to predict listeners' perception of rhythmic regularity within and across domains as well.

Language experience predicts music processing in a half-million speakers of fifty-four languages

Tonal languages differ from other languages in their use of pitch (tones) to distinguish words. Lifelong experience speaking and hearing tonal languages has been argued to shape auditory processing in ways that generalize beyond the perception of linguistic pitch to the perception of pitch in other domains like music. We conducted a meta-analysis of prior studies testing this idea, finding moderate evidence supporting it. But prior studies were limited by mostly small sample sizes representing a small number of languages and countries, making it challenging to disentangle the effects of linguistic experience from variability in music training, cultural differences, and other potential confounds. To address these issues, we used web-based citizen science to assess music perception skill on a global scale in 34,034 native speakers of 19 tonal languages (e.g., Mandarin, Yoruba). We compared their performance to 459,066 native speakers of other languages, including 6 pitch-accented (e.g., Japanese) and 29 non-tonal languages (e.g., Hungarian). Whether or not participants had taken music lessons, native speakers of all 19 tonal languages had an improved ability to discriminate musical melodies on average, relative to speakers of non-tonal languages. But this improvement came with a trade-off: tonal language speakers were also worse at processing the musical beat. The results, which held across native speakers of many diverse languages and were robust to geographic and demographic variation, demonstrate that linguistic experience shapes music perception, with implications for relations between music, language, and culture in the human mind.

The CANDOR corpus: Insights from a large multimodal dataset of naturalistic conversation

People spend a substantial portion of their lives engaged in conversation, and yet, our scientific understanding of conversation is still in its infancy. Here, we introduce a large, novel, and multimodal corpus of 1656 conversations recorded in spoken English. This 7+ million word, 850-hour corpus totals more than 1 terabyte of audio, video, and transcripts, with moment-to-moment measures of vocal, facial, and semantic expression, together with an extensive survey of speakers' postconversation reflections. By taking advantage of the considerable scope of the corpus, we explore many examples of how this large-scale public dataset may catalyze future research, particularly across disciplinary boundaries, as scholars from a variety of fields appear increasingly interested in the study of conversation.

Large-scale iterated singing experiments reveal oral transmission mechanisms underlying music evolution

Speech and song have been transmitted orally for countless human generations, changing over time under the influence of biological, cognitive, and cultural pressures. Cross-cultural regularities and diversities in human song are thought to emerge from this transmission process, but testing how underlying mechanisms contribute to musical structures remains a key challenge. Here, we introduce an automatic online pipeline that streamlines large-scale cultural transmission experiments using a sophisticated and naturalistic modality: singing. We quantify the evolution of 3,424 melodies orally transmitted across 1,797 participants in the United States and India. This approach produces a high-resolution characterization of how oral transmission shapes melody, revealing the emergence of structures that are consistent with widespread musical features observed cross-culturally (small pitch sets, small pitch intervals, and arch-shaped melodic contours). We show how the emergence of these structures is constrained by individual biases in our participants-vocal constraints, working memory, and cultural exposure-which determine the size, shape, and complexity of evolving melodies. However, their ultimate effect on population-level structures depends on social dynamics taking place during cultural transmission. When participants recursively imitate their own productions (individual transmission), musical structures evolve slowly and heterogeneously, reflecting idiosyncratic musical biases. When participants instead imitate others' productions (social transmission), melodies rapidly shift toward homogeneous structures, reflecting shared structural biases that may underpin cross-cultural variation. These results provide the first quantitative characterization of the rich collection of biases that oral transmission imposes on music evolution, giving us a new understanding of how human song structures emerge via cultural transmission.

Level of Attention to Motherese Speech as an Early Marker of Autism Spectrum Disorder

Importance

Caregivers have long captured the attention of their infants by speaking in motherese, a playful speech style characterized by heightened affect. Reduced attention to motherese in toddlers with autism spectrum disorder (ASD) may be a contributor to downstream language and social challenges and could be diagnostically revealing.

Objective

To investigate whether attention toward motherese speech can be used as a diagnostic classifier of ASD and is associated with language and social ability.

Design, Setting, and Participants

This diagnostic study included toddlers aged 12 to 48 months, spanning ASD and non-ASD diagnostic groups, at a research center. Data were collected from February 2018 to April 2021 and analyzed from April 2021 to March 2022.

Exposures

Gaze-contingent eye-tracking test.

Main Outcomes and Measures

Using gaze-contingent eye tracking wherein the location of a toddler's fixation triggered a specific movie file, toddlers participated in 1 or more 1-minute eye-tracking tests designed to quantify attention to motherese speech, including motherese vs traffic (ie, noisy vehicles on a highway) and motherese vs techno (ie, abstract shapes with music). Toddlers were also diagnostically and psychometrically evaluated by psychologists. Levels of fixation within motherese and nonmotherese movies and mean number of saccades per second were calculated. Receiver operating characteristic (ROC) curves were used to evaluate optimal fixation cutoff values and associated sensitivity, specificity, positive predictive value (PPV), and negative predictive value. Within the ASD group, toddlers were stratified based on low, middle, or high levels of interest in motherese speech, and associations with social and language abilities were examined.

Results

A total of 653 toddlers were included (mean [SD] age, 26.45 [8.37] months; 480 males [73.51%]). Unlike toddlers without ASD, who almost uniformly attended to motherese speech with a median level of 82.25% and 80.75% across the 2 tests, among toddlers with ASD, there was a wide range, spanning 0% to 100%. Both the traffic and techno paradigms were effective diagnostic classifiers, with large between-group effect sizes (eg, ASD vs typical development: Cohen d, 1.0 in the techno paradigm). Across both paradigms, a cutoff value of 30% or less fixation on motherese resulted in an area under the ROC curve (AUC) of 0.733 (95% CI, 0.693-0.773) and 0.761 (95% CI, 0.717-0.804), respectively; specificity of 98% (95% CI, 95%-99%) and 96% (95% CI, 92%-98%), respectively; and PPV of 94% (95% CI, 86%-98%). Reflective of heterogeneity and expected subtypes in ASD, sensitivity was lower at 18% (95% CI, 14%-22%) and 29% (95% CI, 24%-34%), respectively. Combining metrics increased the AUC to 0.841 (95% CI, 0.805-0.877). Toddlers with ASD who showed the lowest levels of attention to motherese speech had weaker social and language abilities.

Conclusions and Relevance

In this diagnostic study, a subset of toddlers showed low levels of attention toward motherese speech. When a cutoff level of 30% or less fixation on motherese speech was used, toddlers in this range were diagnostically classified as having ASD with high accuracy. Insight into which toddlers show unusually low levels of attention to motherese may be beneficial not only for early ASD diagnosis and prognosis but also as a possible therapeutic target.

Person-attuned musical interactions (PAMI) in dementia care. Complex intervention research for constructing a training manual

Introduction

Music is of vital importance for cognition, human care, and the formation of social communities throughout life. Dementia is a neurocognitive disorder that affects cognitive domains, and in late-stage dementia, care is needed in all aspects of daily living. Within residential care home contexts, carers play a significant role for the "caring culture" but often lack professional training in verbal and non-verbal communication skills. Thus, there is a need for training carers to respond to the multidimensional needs of persons with dementia. Music therapists use musical interactions but are not trained to train carers. Therefore, our aim was to explore person-attuned musical interactions (PAMI), and additionally, to develop and evaluate a training manual to be used by music therapists when supporting and training carers in non-verbal communication with persons with late-stage dementia in residential care home contexts.

Research process

With a realist perspective and systems thinking and within the framework for complex intervention research, the research group integrated several overlapping subprojects by applying a non-linear and iterative research process. Core elements related to person-centered dementia care as well as learning objectives were considered through the following four phases; Developing, Feasibility, Evaluation, and Implementation.

Results

The result was a training manual for qualified music therapists to use when teaching and collaborating with carers about how to implement PAMI in dementia care. The manual included comprehensive resources, a clear structure for training, defined learning objectives, and integration of theory.

Discussion

With increased knowledge about caring values and non-verbal communication, residential care home cultures may develop carer competencies and provide professional attuned care for persons with dementia. Further piloting and testing to examine the general effect on caring cultures is needed.

Reification of infant-directed speech? Exploring assumptions shaping infant-directed speech research

The seemingly ubiquitous tendency of caregivers to speak to infants in special ways has captivated the interest of scholars across diverse disciplines for over a century. As a result, this phenomenon has been characterized in quite different ways. Here, we highlight the shift from early definitions of “baby-talk” which implied that the nature of speech directed towards infants would vary in different sociolinguistic contexts, to later terms such as “motherese” or “infant-directed speech” (IDS) which came to refer to a specific set of features, some of which were argued to represent a universal, optimal and culturally invariant form of speech. These divergent conceptualizations of IDS thus reflect broader disciplinary tensions pertaining to the role allotted to cultural processes in psychological research. We hope to contribute to this literature by pointing to the complexity associated with identifying discrete categories of speech (i.e., baby-talk and motherese/IDS) within a complex multi-dimensional sociolinguistic landscape. We also highlight ways in which a lack of attention to the cultural context of infant-caregiver interactions may have led to biased characterizations of IDS. Furthermore, these biases may implicitly penetrate the nature of empirical work on IDS as well. We end with a series of suggestions for future directions.