Casey Lew-Williams
Biographic Data
| ID | 5758394 |
|---|---|
| NAME | Casey Lew-Williams |
| GIVEN NAMES | Casey |
| FAMILY NAME | Lew-Williams |
| SIGNATURE | LEW-WILLIAMS C |
| AFFILIATIONS | Princeton University |
| VERIFIED | No |
| TOTAL WORKS | 26 |
| TOTAL CITATIONS | 66 |
| AUTHOR COUNT | 27 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 2007 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 2 |
English-hearing toddlers learn words from consistent and variable labels
Early word learning is traditionally characterized as a process of mapping a single label onto a single referent. Yet, across many languages, child-directed speech (CDS) frequently features multiple labels for the same referent, including diminutivized and reduplicated word forms (e.g., doggy or woof-woof for dog). We examined how consistent versus variable labels impact children's novel word learning. In a within-subjects eye-tracking experiment…
Testing the relationship between preferences for infant-directed speech and vocabulary development: A multi-lab study
From early on, infants show a preference for infant-directed speech (IDS) over adult-directed speech (ADS), and exposure to IDS has been correlated with language outcome measures such as vocabulary. The present multi-laboratory study explores this issue by investigating whether there is a link between early preference for IDS and later vocabulary size. Infants’ preference for IDS was tested as part of the ManyBabies 1 project, and follow-up CDI d…
The high dimensionality of caregiver-child communication: A commentary on Karadöller, Sümer, and Özyürek
Karadöller, Sümer, and Özyürek are doing an important service to the field by emphasizing multimodality in young children’s language learning. They integrate research on speech, gesture, and sign to highlight the independent and combined influence of these modalities on how children learn to communicate. In this commentary, we call for scientists to further broaden the study of natural caregiver-child communication by encompassing a dynamic set o…
Remote Infant Studies of Early Learning (Rise): Scalable online replications of key findings in infant cognitive development
The current article describes the Remote Infant Studies of Early Learning, a battery intended to provide robust looking time measures of cognitive development that can be administered remotely to inform our understanding of individual developmental trajectories in typical and atypical populations, particularly infant siblings of autistic children. This battery was developed to inform our understanding of early cognitive and language development i…
Frequent vs. infrequent words shape toddlers’ real-time sentence comprehension
We examined how noun frequency and the typicality of surrounding linguistic context contribute to children’s real-time comprehension. Monolingual English-learning toddlers viewed pairs of pictures while hearing sentences with typical or atypical sentence frames ( Look at the... vs. Examine the... ), followed by nouns that were higher- or lower-frequency labels for a referent ( horse vs. pony ). Toddlers showed no significant differences in compre…
A unified approach to demographic data collection for research with young children across diverse cultures
Culture is a key determinant of children's development both in its own right and as a measure of generalizability of developmental phenomena. Studying the role of culture in development requires information about participants' demographic backgrounds. However, both reporting and treatment of demographic data are limited and inconsistent in child development research. A barrier to reporting demographic data in a consistent fashion is that no stand…
Caregiver speech predicts the emergence of children's emotion vocabulary
Learning about emotions is an important part of children's social and communicative development. How does children's emotion-related vocabulary emerge over development? How may emotion-related information in caregiver input support learning of emotion labels and other emotion-related words? This investigation examined language production and input among English-speaking toddlers (16–30 months) using two datasets: Wordbank (N = 5520; 36% female, 3…
Moving beyond “nouns in the lab”: Using naturalistic data to understand why infants’ first words include uh-oh and hi
Why do infants learn some words earlier than others? Many theories of early word learning focus on explaining how infants map labels onto concrete objects. However, words that are more abstract than object nouns, such as uh-oh, hi, more, up, and all-gone , are typically among the first to appear in infants' vocabularies. We combined a behavioral experiment with naturalistic observational research to explore how infants learn and represent this un…
Effects of language mixing on bilingual children's word learning
Language mixing is common in bilingual children's learning environments. Here, we investigated effects of language mixing on children's learning of new words. We tested two groups of 3-year-old bilinguals: French–English (Experiment 1) and Spanish–English (Experiment 2). Children were taught two novel words, one in single-language sentences (“Look! Do you see the dog on the teelo?”) and one in mixed-language sentences with a mid-sentence language…
Look at that: Spatial deixis reveals experience-related differences in prediction
Prediction-based theories posit that interlocutors use prediction to process language efficiently and to coordinate dialogue. The present study evaluated whether listeners can use spatial deixis (i.e., this, that, these, and those) to predict the plurality and proximity of a speaker’s upcoming referent. In two eye-tracking experiments with varying referential complexity (N = 168), native English-speaking adults, native English-learning 5-year-old…
Understanding why infant-directed speech supports learning: A dynamic attention perspective
Conventional metaphors elicit greater real-time engagement than literal paraphrases or concrete sentences
Conventional metaphors (e.g., a firm grasp on an idea) are extremely common. A possible explanation for their ubiquity is that they are more engaging, evoking more focused attention, than their literal paraphrases (e.g., a good understanding of an idea). To evaluate whether, when, and why this may be true, we created a new database of 180 English sentences consisting of conventional metaphors, literal paraphrases, and concrete descriptions (e.g.,…
Neural synchrony predicts children's learning of novel words
A Multilab Study of Bilingual Infants: Exploring the Preference for Infant-Directed Speech
From the earliest months of life, infants prefer listening to and learn better from infant-directed speech (IDS) than adult-directed speech (ADS). Yet, IDS differs within communities, across languages, and across cultures, both in form and in prevalence. This large-scale, multi-site study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants' IDS preference. As part of the …
Discontinuity of Reference Hinders Children's Learning of New Words
When referring to objects, adults package words, sentences, and gestures in ways that shape children's learning. Here, to understand how continuity of reference shapes word learning, an adult taught new words to 4-year-old children (N = 120) using either clusters of references to the same object or no sequential references to each object. In three experiments, the adult used a combination of labels and other object references, which provided info…
A multi-lab study of bilingual infants: Exploring the preference for infant-directed speech
From the earliest months of life, infants prefer listening to and learn better from infant-directed speech (IDS) than adult-directed speech (ADS). Yet, IDS differs within communities, across languages, and across cultures, both in form and in prevalence. This large-scale, multi-site study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants’ IDS preference. As part of the …
Quantifying Sources of Variability in Infancy Research Using the Infant-Directed-Speech Preference
Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) as…
Predict and redirect: Prediction errors support children’s word learning
According to prediction-based learning theories, erroneous predictions support learning. However, empirical evidence for a relation between prediction error and children's language learning is currently lacking. Here we investigated whether and how prediction errors influence children's learning of novel words. We hypothesized that word learning would vary as a function of 2 factors: the extent to which children generate predictions, and the exte…
Infants’ selective use of reliable cues in multidimensional language input
Learning always happens from input that contains multiple structures and multiple sources of variability. Though infants possess learning mechanisms to locate structure in the world, lab-based experiments have rarely probed how infants contend with input that contains many different structures and cues. Two experiments explored infants' use of two naturally occurring sources of variability-different sounds and different people-to detect regularit…
When regularization gets it wrong: Children over-simplify language input only in production
Children tend to regularize their productions when exposed to artificial languages, an advantageous response to unpredictable variation. But generalizations in natural languages are typically conditioned by factors that children ultimately learn. In two experiments, adult and six-year-old learners witnessed two novel classifiers, probabilistically conditioned by semantics. Whereas adults displayed high accuracy in their productions – applying the…
Specific Referential Contexts Shape Efficiency in Second Language Processing: Three Eye-Tracking Experiments With 6- and 10-Year-Old Children in Spanish Immersion Schools
Efficiency in real-time language processing generally poses a greater challenge to adults learning a second language (L2) than to children learning a first language (L1). A notoriously difficult aspect of language for L2 learners to master is grammatical gender, and previous research has shown that L2 learners do not exploit cues to grammatical gender in ways that resemble L1 speakers. But it is not clear whether this problem is restricted to gra…
Repetition across successive sentences facilitates young children’s word learning
Young children who hear more child-directed speech (CDS) tend to have larger vocabularies later in childhood, but the specific characteristics of CDS underlying this link are currently underspecified. The present study sought to elucidate how the structure of language input boosts learning by investigating whether repetition of object labels in successive sentences-a common feature of natural CDS-promotes young children's efficiency in learning n…
Infants’ history of distributional learning in real time
Preview this article: Infants’ history of distributional learning in real time, Page 1 of 1 /docserver/preview/fulltext/lab.5.4.09lew-1.gif
Listening through voices: Infant statistical word segmentation across multiple speakers
To learn from their environments, infants must detect structure behind pervasive variation. This presents substantial and largely untested learning challenges in early language acquisition. The current experiments address whether infants can use statistical learning mechanisms to segment words when the speech signal contains acoustic variation produced by changes in speakers' voices. In Experiment 1, 8- and 10-month-old infants listened to a cont…
Grammatical gender in L2: A production or a real-time processing problem
Mastery of grammatical gender is difficult to achieve in a second language (L2). This study investigates whether persistent difficulty with grammatical gender often observed in the speech of otherwise highly proficient L2 learners is best characterized as a production-specific performance problem, or as difficulty with the retrieval of gender information in real-time language use. In an experimental design that crossed production/comprehension an…
Grammatical gender in L2: A production or a real-time processing problem
Mastery of grammatical gender is difficult to achieve in a second language (L2). This study investigates whether persistent difficulty with grammatical gender often observed in the speech of otherwise highly proficient L2 learners is best characterized as a production-specific performance problem, or as difficulty with the retrieval of gender information in real-time language use. In an experimental design that crossed production/comprehension an…
Repetition across successive sentences facilitates young children’s word learning
Young children who hear more child-directed speech (CDS) tend to have larger vocabularies later in childhood, but the specific characteristics of CDS underlying this link are currently underspecified. The present study sought to elucidate how the structure of language input boosts learning by investigating whether repetition of object labels in successive sentences-a common feature of natural CDS-promotes young children's efficiency in learning n…
A unified approach to demographic data collection for research with young children across diverse cultures
Culture is a key determinant of children's development both in its own right and as a measure of generalizability of developmental phenomena. Studying the role of culture in development requires information about participants' demographic backgrounds. However, both reporting and treatment of demographic data are limited and inconsistent in child development research. A barrier to reporting demographic data in a consistent fashion is that no stand…
Listening through voices: Infant statistical word segmentation across multiple speakers
To learn from their environments, infants must detect structure behind pervasive variation. This presents substantial and largely untested learning challenges in early language acquisition. The current experiments address whether infants can use statistical learning mechanisms to segment words when the speech signal contains acoustic variation produced by changes in speakers' voices. In Experiment 1, 8- and 10-month-old infants listened to a cont…
Predict and redirect: Prediction errors support children’s word learning
According to prediction-based learning theories, erroneous predictions support learning. However, empirical evidence for a relation between prediction error and children's language learning is currently lacking. Here we investigated whether and how prediction errors influence children's learning of novel words. We hypothesized that word learning would vary as a function of 2 factors: the extent to which children generate predictions, and the exte…
Young Children Learning Spanish Make Rapid Use of Grammatical Gender in Spoken Word Recognition
All nouns in Spanish have grammatical gender, with obligatory gender marking on preceding articles (e.g., la and el, the feminine and masculine forms of “the,” respectively). Adult native speakers of languages with grammatical gender exploit this cue in on-line sentence interpretation. In a study investigating the early development of this ability, Spanish-learning children (34–42 months) were tested in an eye-tracking procedure. Presented with p…
Real-time processing of gender-marked articles by native and non-native Spanish speakers
Grammatical gender in L2: A production or a real-time processing problem
Mastery of grammatical gender is difficult to achieve in a second language (L2). This study investigates whether persistent difficulty with grammatical gender often observed in the speech of otherwise highly proficient L2 learners is best characterized as a production-specific performance problem, or as difficulty with the retrieval of gender information in real-time language use. In an experimental design that crossed production/comprehension an…
Infants’ history of distributional learning in real time
Preview this article: Infants’ history of distributional learning in real time, Page 1 of 1 /docserver/preview/fulltext/lab.5.4.09lew-1.gif
Listening through voices: Infant statistical word segmentation across multiple speakers
To learn from their environments, infants must detect structure behind pervasive variation. This presents substantial and largely untested learning challenges in early language acquisition. The current experiments address whether infants can use statistical learning mechanisms to segment words when the speech signal contains acoustic variation produced by changes in speakers' voices. In Experiment 1, 8- and 10-month-old infants listened to a cont…
Repetition across successive sentences facilitates young children’s word learning
Young children who hear more child-directed speech (CDS) tend to have larger vocabularies later in childhood, but the specific characteristics of CDS underlying this link are currently underspecified. The present study sought to elucidate how the structure of language input boosts learning by investigating whether repetition of object labels in successive sentences-a common feature of natural CDS-promotes young children's efficiency in learning n…
Specific Referential Contexts Shape Efficiency in Second Language Processing: Three Eye-Tracking Experiments With 6- and 10-Year-Old Children in Spanish Immersion Schools
Efficiency in real-time language processing generally poses a greater challenge to adults learning a second language (L2) than to children learning a first language (L1). A notoriously difficult aspect of language for L2 learners to master is grammatical gender, and previous research has shown that L2 learners do not exploit cues to grammatical gender in ways that resemble L1 speakers. But it is not clear whether this problem is restricted to gra…
When regularization gets it wrong: Children over-simplify language input only in production
Children tend to regularize their productions when exposed to artificial languages, an advantageous response to unpredictable variation. But generalizations in natural languages are typically conditioned by factors that children ultimately learn. In two experiments, adult and six-year-old learners witnessed two novel classifiers, probabilistically conditioned by semantics. Whereas adults displayed high accuracy in their productions – applying the…
Predict and redirect: Prediction errors support children’s word learning
According to prediction-based learning theories, erroneous predictions support learning. However, empirical evidence for a relation between prediction error and children's language learning is currently lacking. Here we investigated whether and how prediction errors influence children's learning of novel words. We hypothesized that word learning would vary as a function of 2 factors: the extent to which children generate predictions, and the exte…
Infants’ selective use of reliable cues in multidimensional language input
Learning always happens from input that contains multiple structures and multiple sources of variability. Though infants possess learning mechanisms to locate structure in the world, lab-based experiments have rarely probed how infants contend with input that contains many different structures and cues. Two experiments explored infants' use of two naturally occurring sources of variability-different sounds and different people-to detect regularit…
Discontinuity of Reference Hinders Children's Learning of New Words
When referring to objects, adults package words, sentences, and gestures in ways that shape children's learning. Here, to understand how continuity of reference shapes word learning, an adult taught new words to 4-year-old children (N = 120) using either clusters of references to the same object or no sequential references to each object. In three experiments, the adult used a combination of labels and other object references, which provided info…
A multi-lab study of bilingual infants: Exploring the preference for infant-directed speech
From the earliest months of life, infants prefer listening to and learn better from infant-directed speech (IDS) than adult-directed speech (ADS). Yet, IDS differs within communities, across languages, and across cultures, both in form and in prevalence. This large-scale, multi-site study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants’ IDS preference. As part of the …
Quantifying Sources of Variability in Infancy Research Using the Infant-Directed-Speech Preference
Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) as…
Conventional metaphors elicit greater real-time engagement than literal paraphrases or concrete sentences
Conventional metaphors (e.g., a firm grasp on an idea) are extremely common. A possible explanation for their ubiquity is that they are more engaging, evoking more focused attention, than their literal paraphrases (e.g., a good understanding of an idea). To evaluate whether, when, and why this may be true, we created a new database of 180 English sentences consisting of conventional metaphors, literal paraphrases, and concrete descriptions (e.g.,…
Neural synchrony predicts children's learning of novel words
A Multilab Study of Bilingual Infants: Exploring the Preference for Infant-Directed Speech
From the earliest months of life, infants prefer listening to and learn better from infant-directed speech (IDS) than adult-directed speech (ADS). Yet, IDS differs within communities, across languages, and across cultures, both in form and in prevalence. This large-scale, multi-site study used the diversity of bilingual infant experiences to explore the impact of different types of linguistic experience on infants' IDS preference. As part of the …
Effects of language mixing on bilingual children's word learning
Language mixing is common in bilingual children's learning environments. Here, we investigated effects of language mixing on children's learning of new words. We tested two groups of 3-year-old bilinguals: French–English (Experiment 1) and Spanish–English (Experiment 2). Children were taught two novel words, one in single-language sentences (“Look! Do you see the dog on the teelo?”) and one in mixed-language sentences with a mid-sentence language…
Look at that: Spatial deixis reveals experience-related differences in prediction
Prediction-based theories posit that interlocutors use prediction to process language efficiently and to coordinate dialogue. The present study evaluated whether listeners can use spatial deixis (i.e., this, that, these, and those) to predict the plurality and proximity of a speaker’s upcoming referent. In two eye-tracking experiments with varying referential complexity (N = 168), native English-speaking adults, native English-learning 5-year-old…
Understanding why infant-directed speech supports learning: A dynamic attention perspective
Caregiver speech predicts the emergence of children's emotion vocabulary
Learning about emotions is an important part of children's social and communicative development. How does children's emotion-related vocabulary emerge over development? How may emotion-related information in caregiver input support learning of emotion labels and other emotion-related words? This investigation examined language production and input among English-speaking toddlers (16–30 months) using two datasets: Wordbank (N = 5520; 36% female, 3…
Moving beyond “nouns in the lab”: Using naturalistic data to understand why infants’ first words include uh-oh and hi
Why do infants learn some words earlier than others? Many theories of early word learning focus on explaining how infants map labels onto concrete objects. However, words that are more abstract than object nouns, such as uh-oh, hi, more, up, and all-gone , are typically among the first to appear in infants' vocabularies. We combined a behavioral experiment with naturalistic observational research to explore how infants learn and represent this un…
Frequent vs. infrequent words shape toddlers’ real-time sentence comprehension
We examined how noun frequency and the typicality of surrounding linguistic context contribute to children’s real-time comprehension. Monolingual English-learning toddlers viewed pairs of pictures while hearing sentences with typical or atypical sentence frames ( Look at the... vs. Examine the... ), followed by nouns that were higher- or lower-frequency labels for a referent ( horse vs. pony ). Toddlers showed no significant differences in compre…
A unified approach to demographic data collection for research with young children across diverse cultures
Culture is a key determinant of children's development both in its own right and as a measure of generalizability of developmental phenomena. Studying the role of culture in development requires information about participants' demographic backgrounds. However, both reporting and treatment of demographic data are limited and inconsistent in child development research. A barrier to reporting demographic data in a consistent fashion is that no stand…
Testing the relationship between preferences for infant-directed speech and vocabulary development: A multi-lab study
From early on, infants show a preference for infant-directed speech (IDS) over adult-directed speech (ADS), and exposure to IDS has been correlated with language outcome measures such as vocabulary. The present multi-laboratory study explores this issue by investigating whether there is a link between early preference for IDS and later vocabulary size. Infants’ preference for IDS was tested as part of the ManyBabies 1 project, and follow-up CDI d…
The high dimensionality of caregiver-child communication: A commentary on Karadöller, Sümer, and Özyürek
Karadöller, Sümer, and Özyürek are doing an important service to the field by emphasizing multimodality in young children’s language learning. They integrate research on speech, gesture, and sign to highlight the independent and combined influence of these modalities on how children learn to communicate. In this commentary, we call for scientists to further broaden the study of natural caregiver-child communication by encompassing a dynamic set o…
Psychology (24 works) · Language Development and Disorders (21 works) · Linguistics (17 works) · Cognitive psychology (15 works) · Developmental psychology (13 works) · Child and Animal Learning Development (12 works) · Reading and Literacy Development (11 works) · Communication (10 works) · Computer Science (10 works) · Neurobiology of Language and Bilingualism (8 works)