Lecture 6.docx

Lecture 6 High amplitude sucking procedure Used to test infants from birth to 4 months Relies on infants sucking reflex Infants hear a sound stimulus every time they produce a strong/high amplitude suck on a pacifier The number of strong sucks is an indicator of the infant's interest 2 variat...

Lecture 6 High amplitude sucking procedure Used to test infants from birth to 4 months Relies on infants sucking reflex Infants hear a sound stimulus every time they produce a strong/high amplitude suck on a pacifier The number of strong sucks is an indicator of the infant's interest 2 variations of the high amplitude sucking procedure 1. Discrimination (between sounds) 2. Preference Discrimination: high amplitude sucking procedure Used to test whether infants can tell the difference between two auditory stimuli Variation of visual habituation paradigm Habituation phase: Each time infant produces a strong suck, a sound is played Continues until sucking has declined significantly (ie. By 20%) Test phase: hear new speech stimuli every time, produces a strong suck If can distinguish between stimuli, sucking behaviour should increase Preference high amplitude sucking procedure used to test preference for different stimuli 2 different stimuli are played on alternating minutes each time a strong suck is produced Ie. Minute 1 = stimulus a, minute 2 = stimulus b, minute 3 = stimulus a Number of strong sucks produced during presentation of each stimulus type is compared Preference: infants suck more during one stimulus type than the other 3 preference of speech perception in infancy using high amplitude sucking paradigms, research has shown that newborns... 1. Prefer to listen to speech sounds over artificial sounds 2. Prefer mother's voice over another woman's voice 3. Prefer to listen to native language vs other language Suggests that language learning starts in utero Often what distinguishes similar speech sounds is... voice onset time (vot) Length of time between when air passes through the lips and when the vocal cords start to vibrate Helps in categorical perception Categorical perception we perceive speech sounds as distinct categories though the differences between speech sounds is gradual /b/ to /p/ continuum these sounds are produced in the same way Their different vots are what accounts for our perception of them as different Vot for /p/ is longer than vot for /b/ /b/ to /p/ continuum: gradually varying voice onset time /b/: <25 ms vot /p/: > 25 ms vot Category boundary: 25 ms Why is categorical perception of speech useful? it focuses listeners on sounds that are linguistically meaningful While ignoring meaningless differences Ie. Difference between a 10 ms vot /b/ versus a 20 ms /b/ is meaningless is English Study setup: infants perceive the same speech categories as adults? classic study by eimas et al. (1971) Tested 1 month old infants learning english High amplitude sucking paradigm to test discrimination between /ba/ and /pa/ 2 groups 2 groups in /ba/ and /pa/ study 1. Different speech sounds: infants habituated to /ba/ (20 ms vot) and then tested with /pa/ (40 ms vot) adults would hear a diff here 2. Same speech sounds: infants habituated to 60 ms vot /pa/ and then tested with 80 ms vot /pa/ adults would perceive the same here Study results: infants perceive the same speech categories as adults? a) different speech sounds: Increased sucking with sound from new category (/pa/ instead of /ba/) B) same speech sounds: No change in sucking when sound from same category (/pa/ versus /pa/) Means that newborns have the same categorical perception of speech as adults Infants make ____ distinctions between speech sounds than adults more Adults have difficulty perceiving differences between speech sounds that aren not important in their native language Ie. In french, difference between /ou/ and /u/ is meaningful, but not in English Study setup: infant cross-language speech perception classic study by werker et al (1988) Tested 6 month old american infants learning english High amplitude sucking paradigm to see if they can discriminate between hindi /ta/ and /ta/ These sounds are not linguistically meaningful in English Study results: infant cross-language speech perception after habituating to one of these hindi speech sounds...they increased sucking when they heard other speech sounds Could tell difference even at 6 months old Ie. If habituated to /ta/, then increased sucking when tested with /ta/ Implications of /ta/ versus /ta/ study infants discriminate between speech sounds they have never heard before (ie. Speech sounds not found in their native language) Infants are biologically ready to learn any of the world's languages Perceptual narrowing of speech perception 8 months old: perceptual discrimination of speech sounds diminishes 10-12 months old: infants lose ability to discriminate between non-native speech sounds Pro of infants losing ability to discriminate between non-native speech sounds improves their perception of speech sounds in native language Word segmentation discovering where words begin and end in fluent speech When does word segmentation begin around 7 months old How do infants "find" words in speech/pick up on patterns? statistical learning: Stress-patterning Distribution of speech sounds Stress patterning diff langs place stress on diff parts of word English: usually initial (first syllable) French: usually ultimate (last syllable) Distribution of speech sounds helps with... word perception Sounds that appear together often are... more likely to be words In all languages, there are sounds that are more or less likely to occur together Ie. "happy baby" "ba" and "by" occur together often to make the word "baby" Sounds that don't appear together often are... more likely to be boundaries between words Ie. "happy baby" "ppy" and "ba" occur together less often because they don't make a word At what age do we use the preferential listening procedure? above 4 months old (kids need to be able to move their heads) Preferential listening procedure speaker on either side of infant's head when looks at speaker, a recording of speech plays different speech comes from each speaker How long an infant spends looking in a particular direction/listening to a particular sound indicates how much they like it Two possible effects in the preferential listening procedure 1. Familiarity effect: will listen longer to sounds they recognize Novelty effect: if first habituated to a sound, will listen longer to a new sound Study setup: distribution of speech sounds preferential listing procedure - are infants able to pick up on co-occurring sequences? Habituation: 8 month olds listened to stream of syllables for a long time (2 mins) some syllables always occurred together Test: presented with a syllable sequence that always co-occurred ("tobiku") versus syllable sequence that rarely occurred ("bagopi") Study results: distribution of speech sounds listened longer to the rarely occurring sequence (more novel) Shows that infants understood word boundaries but detecting the likelihood of syllables b belonging together Even after only 2 mins of exposure, at 8 months old Summary of speech perception 1. Speech perception is studied with... high amplitude sucking procedure preferential listening paradigm 2. Infants have remarkable speech perception abilities from birth, show adult-like categorical perception of speech for sounds that are physically similar from birth, are able to distinguish between speech sounds not found in their native language as they learn sounds of their native language, they lose ability to distinguish between non-native sounds at 10-12 months old Infants are sensitive to the patterns of language and use it to segments words from speech, at about 7 months old Speech: developmental milestones 2 months: cooing, gurgling 7 months: babbling 12 months: first words 18 months: knows 50 words Cooing: when does it begin and what is it? begins at around 2 months old Drawn out vowel sounds Oooh, ahhhhhh Cooing helps with... 1. Helps infants gain motor control over their vocalizations 2. Elicits reactions from caregivers, leading to back-and-forth cooing with caregivers Babbling: when does it begin and what is it? starts at 7 months old (more broadly 6-10) Repetitive consonant-vowel syllables Papapa, bababa Speech sounds not necessarily from native language Is infant babbling similar across languages? yes No attachment with the native language Babbling in deaf infants deaf infants who are exposed to asl: babble with repetitive hand movements made up of pieces or full asl signs Evidence that language exposure is critical for babbling 2 functions of babbling 1. Social function: practicing turn-taking dialogue (conversation) infants' babbling elicits caregiver reactions which in turn elicit more babbling 2. Learning function: signal that the infant is listening and ready to learn infants learn more when an adult labels a new object just after they babble, versus labelling the object in the absence of babbling Infants appear to understand high-frequency words when? at around 6 months old Much before they are able to speak Study: understanding words before speaking their first word show infants pictures of common items and monitor where they look when one of the pictures is named Eye tracking Study results: understanding words before speaking their first word 6 month olds look to the correct picture more often than chance Shows that infants understand more words than they can produce Shows that infants understand more words than their caregivers realize But these words have to be standalone - because word segmentation only occurs at 7 months First word any specific utterance consistently used to refer to or express a meaning Doesn't have to be the correct meaning Can be tricky to identify: babbling can sound like words Ie. "mamamama" meaning of a first word can differ from it's standard meaning Ie. Using "gulgul" to refer to "turkey" When are first words produced? around 12 months of age (10-15 months) Predictable mispronunciations of first words 1. Omit difficult parts of words "banana" becomes "nana" 2. Substitute difficult sounds for easier ones: "rabbit" becomes "wabbit" 3. Re-order sounds to put easy sounds first "spaghetti" becomes "pisketti" But these all count as "first words" because they have consistent meanings What do first words usually refer to? family members, pets, important objects Meaning of first words are very similar across cultures ^suggests that infants around the world have similar interests and priorities 2 limitations of first words infants express themselves initially with only one word utterances, so they cannot clearly communicate what they want to say Overextension Underextension Overextension using a word in a broader context than is appropriate Ie. "dog" refers to any 4 legged animal Doesn't necessarily mean that they don't understand what a dog is Underextension using a word in a more limited context than appropriate Ie. "cat only refers to the family's pet cat How many words do infants know by 18 months of age? about 50 words Vocabulary spurt rate of word learning accelerates Children's assumptions when learning a new word mutual exclusivity Whole-object assumption Pragmatic cues Adult's intentionality Grammatical form Shape bias Cross-situational word learning Mutual exclusivity assumption children assume a given item will only have one name If presented with two objects, one which they know the name of and the other which they do not... Child will turn their attention to the object they don't have a name for when they hear a new word Bilingual children follow this rule less Whole-object assumption children assume a word will refer to the whole object rather than to a part or action of the object Ie. Bunny refers to the whole bunny Pragmatic cues using social context to infer the meaning of a word Adult gaze: when an adult says a new word, the child assumes that it refers to the object the adult is looking at Make this assumption even if the child cannot see what the adult is looking at Adult's intentionality- If an adult uses a word that conflicts with a child's word for that object, they will learn the new word if it is said with confidence Ie. Won't believe adult pointing at a cat and saying "this is a dog" Will believe adult pointing at a cat and saying "you're not going to believe this, but this is actually a dog!" Grammatical form and interpretation as noun, verb or adjective picture of hands tossing grains in a bowl "this is sibbing" - child will automatically know that sibbing is a verb, that it must refer to the action being performed by the hands "this is a sib" - child will infer that sib must refer to the bowl "this is some sib" - child will infer that sib must be the substance inside the bowl Shape bias - word learning children will apply a noun to a new object object of the same shape (even if that shape is very different in size, colour or texture) Cross-situational word learning determining word meanings by tracking the correlations between labels and meanings across contexts Rely on having heard the same word across multiple contexts 3 ways that caregivers influence word learning 1. Infant directed speech (ids) Quantity of speech Quality of speech Infant directed speech (ids) distinctive mode of speech when talking to babies and toddlers Common in majority of cultures around the world Characteristics of ids greater pitch variability Slower speech Shorter utterances Clearer pronunciation of vowels More word repetitions More questions Accompanied by exaggerated facial expressions Functions of ids draws infants' attention to speech Infants prefer ids to regular adult speech Because they pay greater attention to ids, it facilitates their language learning Study setup: ids and early word recognition 7-8 month old infants were introduced to new words either in infant directed speech regular adult speech Recognition of words tested 24 hours later using preferential listening procedure All the speech in the recognition testing had been presented in ids How long do infants look in the direction of the word introduced in ids versus the word introduced in adult speech? Study results: ids and early word recognition infants looked longer at words introduced in ids than adult speech Indicates that ids facilitates recognition of words Number of words children hear used around them... predicts their vocabulary size Children that hear more words have larger vocabularies Ses and speech quantity study found that parents' ses predicts how much speech infants hear Study method: ses and speech quantity tested parents with their 7 month old children over 2.5 years (until the child turned 3) High, middle and low ses Came to lab for an hour every week Everything the parent and child said was recorded and analyzed 30 million word gap from "welfare" to "professional" levels of ses, there is a gap of 30 million words known by these groups of children Implication of effect of ses on vocabulary differences in language exposure contribute to achievement between higher and lower ses children Richness of adult communication with their child predicts... children's language ability Factors contributing to richness of adult communication with child joint engagement Fluency Stressing and repeating new words Playing naming games Naming an object when a toddler is already looking at it Intervention to close the word gap grocery store intervention Grocery store intervention focuses on increasing amount of time parents spend talking to child Signs placed in grocery stores in low ses neighbourhoods encouraging parents to talk to their children about the foods in the store Parents increased quantity and quality of speech to their child Ie. Where does milk come from? Which is your favourite vegetable? Keeping preschoolers with similarly poor language ability in the same classroom... negatively impacts their language growth Better chance to "catch up" on language ability if: placed with children with higher language ability teacher uses rich communication with students Summary of journey to first words 1. Cooing: 2 months old 2. Babbling: 7 months old 3. First words: 4. understand high-frequency words at 6 months old 5. say first words at 12 months old 6. children use variety of strategies to figure out what words mean 7. children's vocabularies are hugely influenced by social context When do first sentences emerge? 2 years old What form do first sentences take? telegraphic speech Telegraphic speech 2-3 word phrases that leave out non-essential words Ie. "mommy cake", "hurt knee", "key door" Common in many languages At what age have children mastered the basics of grammar? 5 years old Allows children to express and understand more complex ideas When do we know that children have learned the grammar of their language? when they can apply a grammatical rule to a new word/context Ie. Adding "s" to make a word plural Overregularization errors speech errors in which children treat irregular forms of words as if they were regular They haven't yet learned the exceptions to the rules, but they're learned the grammatical rules Ie. Mans, goed, foots, breaked, branged 2 ways in which grammar is learned 1. Parents and other caregivers 2. Statistical learning Which do parents correct more: factual or grammatical content? factual, parents rarely correct grammatical errors They model grammatically correct speech but generally don't correct children's grammatical errors Study setup: statistical learning for grammar can infants pick up on new grammatical patterns? Preferential listening paradigm Habituation: to a list of 3-"word" sequences in which second "word" is repeated (abb structure) "le di di" "wi je je" "de li li" Test: presented with new sentences with same structure (abb) or a different structure (aba) Abb: "ko ga ga" Aba: "ko ga ko" Study results: statistical learning for grammar 8 month olds looked longer in direction of sentences with different structure Evidence that infants can pick up on grammatical patterns Speech in children from 1-4 years old exhibits 2 qualities... Children initially struggle to engage in mutual conversation Private speech Infants' speech is often initially directed to themselves to organize actions Egocentric discussion between children Speech in children from 5+ years old... able to stick to the same conversation topic as their conversation partner Summary of putting words together age 2: produce 2-3 word sentences Age 2-5: acquire the basics of grammar Age 5: master grammar and begin to be able to engage in sustained conversations Sensitive period for language acquisition period from birth to before puberty Crucial period in which an individual can acquire a first language if exposed to adequate linguistic stimuli Languages are learned relatively easily during this period And full native competence is possible What is the sensitive period for language acquisition due to? due to maturational changes in the brain whereby language brain areas become less plastic After the sensitive period for language acquisition has passed... languages are learned with great difficulty and native-like competence is rare Especially with things like pronounciation Genie: evidence for sensitive period in language acquisition from 18 months old until she was rescued at age 13, she was deprived of linguistic input Could barely speak Development was also stunted in other areas Language ability never developed despite intensive training after age 13 Evidence of sensitive period of language acquisition When/where was genie discovered? in 1970, in la Example of genie's speech even after intensive training "father take piece wood. Hit. Cry" Instead of sensitive period, genie's difficulties could be due to... inhumane treatment rather than linguistic deprivation per se Children that sustain brain damage to language areas... usually recover full language capability Children's brains are highly plastic Other parts of developing brain take over language functions Teens and adults that sustain brain damage to language areas... are more likely to suffer permanent language impairment More mature brain is less plastic Observational study setup: evidence for importance of early language exposure - deaf individual researchers tested 2 groups of deaf adults No exposure to any form of language (spoken or signed) during early childhood Learned spoken language during early childhood's, and then went deaf Both groups began learning asl: in school between ages 9-15 Observational study results: evidence for importance of early language exposure - deaf individuals those with exposure to language in infancy, even though it was spoken, performed better on language task than those with no language exposure Follow up study: deaf individuals and language exposure tested deaf adults that had exposure to asl in early childhood Performance of deaf adults with early exposure to asl was the same as deaf adults with exposure to spoken language Shows that exposure to language, regardless of modality, in infancy is critical for full language development Korean and chinese immigrants: evidence for importance of early language exposure performance on an english test by chinese and korean immigrants was related to the age at which they first arrived in canada Show that language proficiency is related to first age of exposure to that language Language performance is highly _________ when a language is learned after puberty Variable 2 implications of sensitive period in language acquisition 1. Deaf children should be exposed to sign language as young as possible to develop native-like ability Second language exposure at school should begin as early as possible to maximize opportunity to achieve native-like ability About __% of people across the world use at least 2 languages on a daily basis 50 __% of canadians are english-french bilingual 17 __% of montrealers are english-french bilingual 55 __% of canadians' first language is neither english nor French 20 Myth of the monolingual brain belief that infants' brains are programmed to be monolingual and that they treat input in 2 languages as if it were one language Bilingualism stretches limited processing capacity of infants This is wrong Implications of the monolingual brain hypothesis if bilingual from birth, children will confuse their languages Could result in language delays We know the monolingual brain hypothesis is wrong, partly because... of bilingualism in utero Study setup: bilingualism in utero bilingual learning begins in utero Study tested 2 groups of newborn infants Bilingual english-tagalog mothers Monolingual english mothers Preferential high amplitude sucking procedure Exposed infants to tagalog and english sentences Measured rates of sucking on a pacifier More intense sucking indicates preference for one language Kids show preference for native language, so what will the bilingual newborns do? Study results: bilingualism in utero english monolinguals had preference for english English-tagalog bilinguals showed no consistent preference for either language Suggests that bilingual infants start learning about two native languages pre-birth But maybe this really just reflects them not learning either language... Study setup: bilingualism in utero 2 in response to idea from first bilingual study that maybe there's no preference for either language because neither is being learned Tested if bilingual infants can differentiate between two native languages Tested 2 groups of newborns Bilingual english-tagalog mothers Monolingual english mothers Discrimination high amplitude sucking procedure Study habituation and test: bilingualism in utero 2 habituation: both groups were habituated to english or tagalog until sucking declined Test: hearing sentences in new language Study results: bilingualism in utero 2 both bilingual babies and monolingual babies differentiated between tagalog and english Shows that bilingual infants can differentiate between native languages despite showing similar preference for both languages Even in newborns! Bilingualism in the womb Bilingual infants: two separate linguistic systems high amp sucking procedure study with english-tagalog exposed infants suggests... That bilingual infants are developing two separate language systems. They differentiate the linguistic inputs Rather than confusing two languages Goes against the monolingual brain hypothesis 3 pieces of evidence for 2 separate linguistic systems 1. Language development in bilingual vs monolingual children is similar say first word at roughly same time have about the same vocabulary size as monolinguals when you add words from all languages together Children select language they use based on their conversation partner Even if children mix languages, this isn't a sign of confusion language mixing in adult bilinguals is normal 90% of bilingual parents mix their languages in speech Bilingual children perform better on measures of _________ _____________________ than monolingual children executive functioning Bilingualism delays onset of _________________ in older adults alzheimer's Why is bilingualism advantageous? bilingual individuals have to quickly switch between languages This practices their executive functioning skills Especially cognitive flexibility 2 positive effects of bilingualism 1. Bilingual children perform better on measures of executive functioning than monolingual children Bilingualism seems to delay the onset of alzheimer's in older adults Implications of findings on bilingualism schools should support learning both native and non-native language from a young age 3 summary points of bilingualism in infants 1. Contrary to monolingual brain hypothesis, bilingual children simultaneously acquire a linguistic system for each of their languages Start learning both (or more than 2) languages of the family in utero Bilingual language development is very similar to monolingual development