Infant-Directed Speech and Song (PSYC 211, Fall 2024) PDF

W13: Infant-directed speech and song PSYC 211  Outline Basics of language and speech development Methods for studying language/speech perception in infants Infant directed speech: What is it and what is the function? Infant-directed song: What...

W13: Infant-directed speech and song PSYC 211  Outline Basics of language and speech development Methods for studying language/speech perception in infants Infant directed speech: What is it and what is the function? Infant-directed song: What is it and what is the function? Cross-cultural infant-directed speech and song  Learning outcomes Describe two hypotheses on brain specialisation for language Define critical periods for language acquisition and discuss evidence/challenges Define babbling and its key stages Explain the role of gesture in language development Outline the trajectory of language comprehension in infants  Section 1: Basics of infant development and language acquisition From Hoff, E. (2009). Language development. Belmont, CA, USA:: Wadsworth Cengage Learning. Cognitive neuroscience basics: Brain development for language Development of auditory system ~ 20 weeks gestation Remember: Language is more than speech (auditory) So what else needs to develop?  Two hypothesis on brain development and language 1) Equipotentiality hypothesis: No hemispheric specialisation for language at birth Specialisation of left hemisphere comes later 2) Invariance hypothesis: Hemispheric specialisation for language at birth Comparable left hemisphere organisation to adults Hoff, 2008  Evidence for the invariance hypothesis Left-hemisphere > Right-hemisphere when young infants hear speech sounds (fMRI & EEG studies) Children with aphasia tend to have left-hemisphere damage over right-hemisphere damage…BUT there is plasticity for acquiring language (equipotentiality) Infants open right side of mouth more when babbling, but not when making other vocalisations Hoff, 2008  Critical period for language acquisition Critical period = time window during [biological] development during which an ability must be acquired Input from environment + biology = acquisition Examples: Non-human animals: Imprinting in birds Humans: Language… Challenge: How do you test a critical period for language acquisition? Hoff, 2008  Critical period for language acquisition: Evidence Case studies Genie: no language exposure until age 13 Acquires some semantics -> map words to meanings Does not acquire full syntax (grammar) Example: “Mama wash hair in sink” Challenge: Complex personal histories Other developmental delays at play? Hoff, 2008  Critical period for language acquisition: Evidence Learning languages later in life 1) Sign language: Early-learners have better grammar than late-learners 2) Second language: Younger learners are more proficient than later learners Any challenges to these approaches? Hoff, 2008  TL;DR: Some evidence for the invariance hypothesis, but not air-tight Evidence consistent with a critical period for language acquisition, but it’s really hard to experimentally demonstrate this  Infant Speech Production: Babbling Babbling: production of sounds that involves phonemes spanning human languages 12  Developmental Stages of Babbling Quasi-resonant vocalisation (QRV): whiny vocalisations, not fully resonant Fully-resonant vowel (FRV): more speech-like, vowel sounds only (3-4 mo) Marginal-syllable: consonant and vowel sounds with slow transition between them (4-8 mo) Canonical-syllable: ‘typical’ syllable sequences for a language (9 mo) Example: da-da-da, ta-ta-ta 13  Babbling Perceptual attunement: General sounds -> Language-specific sounds over first year of life Extends to comprehension! More to come on this…  Gesture as a pre-cursor to language Recall: Language is a symbolic system of communication Cat Developmental roots in non-symbolic gesture? Chat Kissa Pre-linguistic infants use gesture to communicate Pointing + eye gaze Hoff, 2008  Gesture as a pre-cursor to language Iconic gesture: Gestures that clearly map to their referent (meaning, object) Pre-symbolic “Give” gesture “All gone” gesture “Flower” gesture Hoff, 2008  Gesture meets Language Over development, gesture and language get combined “dog” “more” Hoff, 2008  Developmental trajectory of language comprehension D’Odorico et al. (2001) % of participants Survey infant’s language comprehension over first ~2 years of life Parental reports Months of Age 18  Language Comprehension in Infants: The noun explosion Rapid acquisition of words beginning around year 2 of life Name vs verb explosion? Other words Nouns = ~34 % = ~33 % Nouns = Other words ~49 % = ~56 % Function words = ~9 % Predicates = ~5 % Predicates = ~10 % Function words = ~6 % Earlier developmental Later developmental stage stage 19 D’Odorico et al. (2001)  Outline Basics of language and speech development Methods for studying language/speech perception in infants Infant directed speech: What is it and why do we do it? Infant-directed song: What is it and why do we do it? Cross-cultural infant-directed speech and song  Learning Outcomes Name and describe the basic components of three behavioural methods for studying language comprehension in infants Explain the logic of each method 3 key behavioural methods for measuring speech perception in infants What you predict influences which method you choose 1) Looking-Time Preference Procedure 2) Head-Turn Procedure 3) Habituation Procedure  Method 1 Looking-Time Preference Procedure: What do infants like? Logic: If infant looks longer in one direction, then infant prefers that sound.  Method 2 Head-turn Procedure: Do infants detect a change in sound? Logic: If infants turn head when a change in the auditory stimulus happens, then they detected the change.  Method 3 Habituation procedure: Do infants detect Logic: If infants look novelty/changes in sound? longer at novel sounds, then they detect a change. Decrease looking time Repeat: dadadadadadada… Increase looking time dadadaBAdadad  Outline Basics of language and speech development Methods for studying language/speech perception in infants Infant directed speech: What is it and why do we do it? Infant-directed song: What is it and why do we do it? Cross-cultural infant-directed speech and song  Three big questions about infant-directed speech 1) What is infant-directed speech? 2) How does infant-directed speech affect language acquisition? 3) Does everyone use infant-directed speech? Are there cultural differences in infant-directed speech?  Learning Outcomes Define infant-directed speech (IDS) and its properties Answer the question: How might IDS influence language acquisition? Use evidence to support your answer Describe (briefly!) evidence for cultural differences and similarities in IDS  Three big questions about infant-directed speech 1) What is infant-directed speech? 2) How does infant-directed speech affect language acquisition? 3) Does everyone use infant-directed speech? Are there cultural differences in infant-directed speech?  Communicating with Infants Infant-directed communication: The tendency to alter how we communicate with infants Infant-directed speech: Modulate speech sounds in specific ways when interacting with infants Hyperarticulation of vowels More variable speech pattern (pitch) Higher F0 Slower speech/longer pauses  IDS use changes across development Rattansone et al. (2013) -Compared IDS and ADS in Cantonese speakers (tonal language) -Measured acoustic features: Pitch, vowel hyperarticulation, tone hyperarticulation 3 tones of interest: High-rising, high-level, low rising Question: Do speakers systematically vary certain acoustic features when they engage in IDS with younger vs older children?  IDS use changes across development Younger age = more tone hyperarticulation Tone Hyperarticulation compared to ADS Evidence that IDS persists across first year of life Exact acoustic changes vary by age of infant Target Age Rattansone et al. (2013)  Three big questions about infant-directed speech 1) What is infant-directed speech? 2) Does infant-directed speech affect language acquisition? 3) Does everyone use infant-directed speech? Are there cultural differences in infant-directed speech?  How might IDS affect language acquisition? Study 1: Exaggerate different sounds Study 2: Clarity of important sounds  Study 1: Does exaggeration in IDS affect infants’ perception of speech sounds? Test phase Habituation phase Compare infant looking times between Trial 1 Trial 1: “sh” + “a”, “o” and Trial 2 “sh” + “a”, “o” OR Trial 2: “s” + “a”, “o” They ALSO measured: Question: Does caregiver speech variability relate to Caregiver’s variability infants’ detection of in ‘sh’ and ‘s’ sounds different S sounds? Cristia (2011)  Study 1: Does exaggeration in IDS affect infants’ perception of speech sounds? Question: Does caregiver speech variability relate to infants’ detection of different S sounds? Yes! Caregivers who made a bigger distinction between ‘s’ and ‘sh’ = infants looked more at the novel ‘s’ than the habituated ‘sh’ Implication: Creating more variability in speech sounds may facilitate speech sound perception Related to clarity of the sounds? Beneficial in language acquisition – why? Cristia (2011)  Study 2: Does clarity of important sounds affect word recognition? Vowel hyperarticulation: Where’s the cup? Measure looking time to the target object (this No vowel example = hyperarticulation: cup) Where’s the cup? Question: Do children look longer at the target item (cup) than the distractor item (book)? Song et al. (2010)  Study 2: Does clarity of important sounds affect word recognition? Question: Do children look longer at the target item (cup) Proportion time looking 80 than the distractor item (book)? at target object 60 40 More vowel hyperarticulation (exaggeration) = better word recognition 20 How we alter vowel sounds in 0 IDS Non-IDS IDS affects word recognition (not Hyperarticulation No hyperarticulation just attention!) Speech Condition Song et al. (2010)  Three big questions about infant-directed speech 1) What is infant-directed speech? 2) Does infant-directed speech affect language acquisition? 3) Does everyone use infant-directed speech? Are there cultural differences in infant-directed speech? Speech Beijing San Diego Mantawai Islands  Speech 1) 2) 3) 4) 5) 6) Hilton et al., 2022  Some evidence that IDS varies across cultures… Schneidman & Goldin-Meadow (2012) Compared use of (infant-directed) speech in English-speaking children (USA) and Yucatec Mayan-speaking children (indigenous group in Mexico) Naturalistic observation in daily environments Measured: How much infants are spoken to and trajectory of language acquisition  Some evidence that use of IDS varies across cultures… Infant-directed speech Overheard speech More speech directed at children in the US than the Mayan group Not all cultures speak to children the same way Schneidman & Goldin-Meadow (2012)  Some evidence that features of IDS cross cultures… Werker (1994) Recruited English-speaking babies and Cantonese-speaking infants Played videos of Cantonese speaker using IDS and ADS Compared how long English-speaking infants and Cantonese- speaking infants looked at IDS vs ADS  Infant-directed speech: Crossing cultures Younger infants > IDS IDS > ADS Werker (1994) 3) Are there cultural differences in infant-directed speech? Recap: Not all cultures speak to infants the same way Evidence that infant-specific vocalisations may have qualities and functions that transcend culture  Outline Basics of language and speech development Methods for studying language/speech perception in infants Infant directed speech: What is it and why do we do it? Infant-directed song: What is it and why do we do it? Cross-cultural infant-directed speech and song  In addition to speaking to infants in a particular way, sometimes we sing to infants in a particular way too. Infant-directed song!  Learning Outcomes By the end of this section, you should be able to use evidence to answer the following questions: 1) Do infants like infant-directed song? 2) What are some possible functions of infant-directed song? 3) Can people recognise infant-directed song across cultures? 4) From (3), what does this tell us about infant-directed song?  Do adults recognise infant-directed singing? Question 1: Do adults, from the same culture, recognise infant-directed singing from adult-directed singing? Sing to your infant Rated as IDSong or ADSong Sing to an adult Trainor, 1996  Do people actually recognise infant-directed singing? Results ~ 93% of songs correctly classified as IDSong or ADSong IDSong = “more loving” than ADSong -> what does this mean? People generally differentiate play songs from lullabies Play songs more rhythmic Question: Do adults, from the same culture, recognise infant-directed singing? Answer? Trainor, 1996  Do infants even like infant-directed singing? Question 2: Do infants prefer IDSong over ADSong? Preference Procedure Measure looking time Trainor (1996)  Do infants like infant-directed singing? % Time Looking at IDSong Question: Do infants prefer * IDSong over ADSong? Play songs Lullabies Trainor (1996) Adults recognise IDSong Infants prefer IDSong What is the function of IDSong? Why do we sing to infants?  Does infant-directed singing affect language acquisition? Perceptual attunement: General sounds -> Language-specific sounds over first year of life Extends to comprehension! “Narrowing window” for perception of speech sounds outside your language Question: Does infant-directed singing affect perceptual attunement?  Does infant-directed singing affect language acquisition? Experiment 1: Infant-directed speech Familiar vowel: goo-goo-goo vs Unfamiliar vowel: goo-geuh- Infant-directed singing goo-geuh 4-6 mo Question: Do infants look longer at the unfamiliar vowel sequence after song vs speech? Falk et al. (2020)  Does infant-directed singing affect language acquisition? Experiment 1: Question: Do infants look longer at the unfamiliar vowel sequence after song vs speech? Infants can discriminate unfamiliar vowel sound but… No difference between song and speech conditions! Falk et al. (2020)  Does infant-directed singing affect language acquisition? Experiment 2: Repeats experiment 1, but with older infants Infant-directed speech Familiar vowel: goo-goo-goo vs Unfamiliar vowel: goo-geuh- Infant-directed singing goo-geuh 8-10 mo Question: Do infants look longer at the unfamiliar vowel sequence after song vs speech? Falk et al. (2020)  Does infant-directed singing affect language acquisition? Experiment 2: Question: Do infants look longer at the unfamiliar vowel sequence after song vs speech? Infants can discriminate unfamiliar vowel sound and… difference between song and speech conditions! Falk et al. (2020) Does infant-directed singing affect language acquisition? Interpretation of Falk et al. (2020) data: Infant-directed song may be ‘holding open’ the perceptual attunement window Younger infants not affected by song vs speech Older infants, who are undergoing perceptual attunement, are affected by song vs speech How might holding open the perceptual attunement window affect speech/language acquisition?  Does infant-directed singing affect social cognition? Infant-directed singing is very rhythmic Predictable Predictable stimuli might be useful to infants Time certain behaviours to the rhythm Anticipate important information Look towards people’s faces on the rhythm Core idea: Important social cues may be conveyed through rhythms in infant-directed speech  Does infant-directed singing affect social cognition? 2 mo 6 mo Question: Do infants look at the singers’ eyes more on the beat of the rhythm? Lense et al. (2022)  Change in probability of Does infant-directed singing affect social cognition? eye looking Time (ms) Time (ms) 2 mo 6 mo Young and older infants look in singer’s eyes on beat Lense et al. (2022) Older > younger  Does infant-directed singing affect social cognition? What is the singer doing on the beat? What does this mean Change in probability of for social cues? wide-eyed (+) affect How do we integrate what the infant is doing with what the singer is doing? Time (ms) Lense et al. (2022)  Does infant-directed singing affect social cognition? Infants look into a singer’s eyes more on the beat of a rhythm Singers modulate their facial expressions with the beat of the rhythm Implication/take home message: Infant-directed singing may be an opportunity for infants to get more social cues Rhythm of infant-directed singing is important -> missing from infant-directed speech! Lense et al. (2022) Are there cultural differences in infant-directed singing? Song Turku Toronto Vanuatu (Tannese) Song 1) 2) 3) 4) 5) 6)  The paper you read today! Hilton et al. (2022): Discuss in groups of 3 What was the main goal/aim of each study? BRIEF method: Who participated? What did participants do? What was manipulated (IV)? What did the researchers measure? Key finding for speech in each experiment Key finding for song in each experiment What is the take home message from this research article?  The paper you read today! Hilton et al. (2022) Trained a computational model to Large cross-cultural study classify speech and song as: Infant-directed Speech and song clips from OR people across 21 different Adult-directed societies Results: Model was good at correctly First question: Do infant- classifying clips as infant-directed or and adult- directed speech adult-directed! and song systematically vary True for speech and song across cultures?  The paper you read today! Hilton et al. (2022) Large cross-cultural study Speech and song clips from people across 21 different societies Second question: Are infant- and adult-directed speech and song recognised across cultures? Tested ~50 000 people  The paper you read today! Do people distinguish infant- from adult-directed SPEECH? Infant-directedness rating Do people distinguish infant- from adult-directed SONG? What is the take-home message? Are infant-directed song and infant-directed speech universal? Justify!  Reminder: Final Exam: Monday, December 9 Time: 09h-12h00 Location: AB K 149 Closed-book Non-cumulative (unless important concepts showed up in both halves of course) -> not re-tested on SPECIFICS from pre-midterm material Topics: Long-term memory, mental imagery, language, language acquisition/IDS/IDSong