Infrastructural theory of human language and its origins
Oller, D. K. The Emergence of the Speech Capacity (2000). Erlbaum. This project and its publications provide a theoretical framework for all the other
projects in the laboratory, and a basis for collaboration with a wide variety of additional
institutions and scholars. The key idea is that language is founded in capabilities
that emerge systematically and in an ordered fashion starting in very early infancy.
Primitive capabilities to vocalize and use vocalization as well as to express affect
facially and through bodily movements form the basis for more advanced capabilities
that are built upon them.
Oller, D. K., Dale, R., Griebel, U. (2016). New frontiers in language evolution and
development: the Editors’ Introduction. In New Frontiers in Language Evolution and
Development Edited by: Wayne D. Gray. Topics in Cognitive Science (topiCS), 8(2),
353-360. Abstract: This article introduces the Special Issue and its focus on research in language
evolution with emphasis on theory as well as computational and robotic modeling. A
key theme is based on the growth of evolutionary developmental biology or evo-devo.
The Special Issue consists of 13 articles organized in two sections: A) Theoretical
foundations and B) Modeling and simulation studies. All the papers are interdisciplinary
in nature, encompassing work in biological and linguistic foundations for the study
of language evolution as well as a variety of computational and robotic modeling efforts
shedding light on how language may be developed and may have evolved.
Oller, D. K., Griebel, U., & Warlaumont, A. S. (2016). Vocal development as a guide
to modeling the evolution of language. In New Frontiers in Language Evolution and
Development Edited by: Wayne D. Gray. Topics in Cognitive Science (topiCS), 8(2),
382-392. Abstract: Modeling of evolution and development of language has principally utilized
mature units of spoken language, phonemes and words, as both targets and inputs. This
approach cannot address the earliest phases of development because young infants are
unable to produce such language features. We argue that units of early vocal development—protophones
and their primitive illocutionary/perlocutionary forces—should be targeted in evolutionary
modeling because they suggest likely units of hominin vocalization/communication shortly
after the split from the chimpanzee/bonobo lineage, and because early development
of spontaneous vocal capability is a logically necessary step toward vocal language,
a root capability without which other crucial steps toward vocal language capability
are impossible. Modeling of language evolution/development must account for dynamic
change in early communicative units of form/function across time. We argue for interactive
contributions of sender/infants and receiver/caregivers in a feedback loop involving
both development and evolution and propose to begin computational modeling at the
hominin break from the primate communicative background.
Empirical work on origins of communication in humans and animals (human infants and
children, bonobos, dog, wolf, and squid)
Griebel, U. & Oller, D. K. (2008). Evolutionary forces favoring contextual flexibility.
In Oller, D.K. and Griebel, U. (editors) Evolution of Communicative Flexibility: Complexity,
Creativity, and Adaptability in Human and Animal Communication, MIT Press pp. 9-40.
This chapter defines “signal flexibility” and “functional flexibility” as two kinds
of contextual flexibility in communication. It evaluates the environmental/social
conditions and communication types that seem to favor selection for variability or
complexity in communication systems and which may result in signal and functional
flexibility. The chapter also presents clear cases of actions such as camouflage and
deception, and proposes that some degree of signal flexibility is a prerequisite for
functional flexibility. It analyzes the occurrence of the various mapping options
for signals and functions in nonhumans from invertebrates to primates, and suggests
that human communicative flexibility first emerged under pressures of social cohesion.
Griebel, U., & Oller, D. K. (2014). Origins of language in a comparative perspective.
In P. J. Lafreniere & G. Weisfeld (Eds.), Evolutionary Science of Human Behavior:
An Interdisciplinary Approach. Linus Learning, Rokokoma, NY. 257-280. Since our cognitive abilities have evolved from those of our ancestors, we suggest
a comparative approach to enlightening us about language origins, examining animal
language learning studies to determine what animals actually can come to understand
about human language. This approach may lead to better understanding of the cognitive
underpinnings of language. It will definitely help to pinpoint features that seem
to be uniquely involved in human language, ones that may be present to lesser extents
in animal communication, as well as ones that are shared across many species.
Oller, D. K. & Griebel, U. (2014). On Quantitative Comparative Research in Communication
and Language Evolution. Biological Theory, 9, 2, 296-308. doi: 10.1007/s13752-014-0186-7.
NIHMSID #613148. PMCID: PMC4179202. Abstract: Quantitative comparison of human language and natural animal communication
requires improved conceptualizations. We argue that an infrastructural approach to
development and evolution incorporating an extended interpretation of the distinctions
among illocution, perlocution, and meaning (Austin 1962; Oller and Griebel 2008) can
help place the issues relevant to quantitative comparison in perspective. The approach
can illuminate the controversy revolving around the notion of functional referentiality
as applied to alarm calls, for example in the vervet monkey. We argue that referentiality
offers a poor point of quantitative comparison across language and animal communication
in the wild. Evidence shows that even newborn human cry could be deemed to show functional
referentiality according to the criteria typically invoked by advocates of referentiality
in animal communication. Exploring the essence of the idea of illocution, we illustrate
an important realm of commonality among animal communication systems and human language,
a commonality that opens the door to more productive, quantifiable comparisons. Finally,
we delineate two examples of infrastructural communicative capabilities that should
be particularly amenable to direct quantitative comparison across humans and our closest
relatives.
Griebel, U., Pepperberg, I., Oller, D. K. (2016). Developmental Plasticity and Language:
A Comparative Perspective. In New Frontiers in Language Evolution and Development
Edited by: Wayne D. Gray. Topics in Cognitive Science (topiCS). 8(2), 435-445. Abstract: The growing field of evo-devo is increasingly demonstrating the complexity
of steps involved in genetic, intracellular regulatory, and extracellular environmental
control of the development of phenotypes. A key result of such work is an account
for the remarkable plasticity of organismal form in many species based on relatively
minor changes in regulation of highly conserved genes and genetic processes. Accounting
for behavioral plasticity is of similar potential interest but has received far less
attention. Of particular interest is plasticity in communication systems, where human
language represents an ultimate target for research. The present paper considers plasticity
of language capabilities in a comparative framework, focusing attention on examples
of a remarkable fact: Whereas there exist design features of mature human language
that have never been observed to occur in non-humans in the wild, many of these features
can be developed to notable extents when non-humans are enculturated through human
training (especially with intensive social interaction). These examples of enculturated
developmental plasticity across extremely diverse taxa suggest, consistent with the
evo-devo theme of highly conserved processes in evolution, that human language is
founded in part on cognitive capabilities that are indeed ancient and that even modern
humans show self-organized emergence of many language capabilities in the context
of rich enculturation, built on the special social/ecological history of the hominin
line. Human culture can thus be seen as a regulatory system encouraging language development
in the context of a cognitive background with many highly conserved features.
Tchernichovski, O. & Oller, D. K. (2016) Vocal Development: How marmoset infants express
their feelings. Current Biology. 26(10), R422-R424. Abstract: A new study shows that vocal sequences produced by newborn marmoset monkeys
are driven by slow fluctuations in physiological state; the results shed light on
the evolution of vocal communication between newborns and parents.
Griebel U., Oller D.K. (2012) Vocabulary learning in a Yorkshire terrier: Slow mapping
of spoken words. PLoS ONE. 7(2): e30182. doi:10.1371/journal.pone.0030182. Abstract: Rapid vocabulary learning in children has been attributed to "fast mapping",
with new words often claimed to be learned through a single presentation. As reported
in 2004 in Science a border collie (Rico) not only learned to identify more than 200
words, but fast mapped the new words, remembering meanings after just one presentation.
Our research tests the fast mapping interpretation of the Science paper based on Rico's
results, while extending the demonstration of large vocabulary recognition to a lap
dog. We tested a Yorkshire terrier (Bailey) with the same procedures as Rico, illustrating
that Bailey accurately retrieved randomly selected toys from a set of 117 on voice
command of the owner. Second we tested her retrieval based on two additional voices,
one male, one female, with different accents that had never been involved in her training,
again showing she was capable of recognition by voice command. Third, we did both
exclusion-based training of new items (toys she had never seen before with names she
had never heard before) embedded in a set of known items, with subsequent retention
tests designed as in the Rico experiment. After Bailey succeeded on exclusion and
retention tests, a crucial evaluation of true mapping tested items previously successfully
retrieved in exclusion and retention, but now pitted against each other in a two-choice
task. Bailey failed on the true mapping task repeatedly, illustrating that the claim
of fast mapping in Rico had not been proven, because no true mapping task had ever
been conducted with him. It appears that the task called retention in the Rico study
only demonstrated success in retrieval by a process of extended exclusion.
Studies of communication development in typically developing human infants
Oller, D. K., Buder, E. H., Ramsdell, H. L., Warlaumont, A. S., Chorna, L., & Bakeman,
R. (2013). Functional flexibility of infant vocalization and the emergence of language.
Proceedings of the National Academy of Sciences. 110 (16) 6318-6323. doi:10.1073/pnas.1300337110/-/DCSupplemental.
PMCID: PMC3631625. Abstract: We report on the emergence of functional flexibility in vocalizations of
human infants. This vastly underappreciated capability becomes apparent when prelinguistic
vocalizations express a full range of emotional content—positive, neutral, and negative.
The data show that at least three types of infant vocalizations (squeals, vowel-like
sounds, and growls) occur with this full range of expression by 3–4 months of age.
In contrast, infant cry and laughter, which are species-specific signals apparently
homologous to vocal calls in other primates, show functional stability, with cry overwhelmingly
expressing negative and laughter positive emotional states. Functional flexibility
is a sine qua non in spoken language, because all words or sentences can be produced
as expressions of varying emotional states and because learning conventional "meanings"
requires the ability to produce sounds that are free of any predetermined function.
Functional flexibility is a defining characteristic of language, and empirically it
appears before syntax, word learning, and even earlier-developing features presumed
to be critical to language (e.g., joint attention, syllable imitation, and canonical
babbling). The appearance of functional flexibility early in the first year of human
life is a critical step in the development of vocal language and may have been a critical
step in the evolution of human language, preceding protosyntax and even primitive
single words. Such flexible affect expression of vocalizations has not yet been reported
for any non-human primate but if found to occur would suggest deep roots for functional
flexibility of vocalization in our primate heritage.
Nathani Iyer, S., Denson, H., Lazar, N. & Oller, D. K. (2016) Volubility of the human
infant: Effects of parental interaction (or lack of it). Clinical Linguistic & Phonetics.
DOI:10.3109/02699206.2016.1147082, 80747, PMC4902155. Abstract: Although parental volubility, or amount of talk, has received considerable
recent attention, infant volubility has received comparatively little attention despite
its potential significance for communicative risk status and later linguistic and
cognitive outcomes. Volubility of 16 typically developing infants from 2 to 11 months
of age was longitudinally investigated in the present study across three social circumstances:
parent talking to infant, parent not talking to infant and parent talking to interviewer
while the infant was in the room. Results indicated that volubility was least in the
Interview circumstance. There were no significant differences in volubility between
the parent Talk and No Talk circumstances. Volubility was found to reduce with age.
These results suggest that infants vocalize in a variety of circumstances, even when
no one talks to or interacts with them. The presence of a stranger or perhaps overhearing
adults speaking to each other, however, may significantly reduce infant volubility.
Jhang. Y., & Oller, D. K (2017). Emergence of Functional Flexibility in Early Infant
Vocalization of the First Three Months: Analyses of laboratory recordings. Frontiers
in Psychology. 8, DOI:10.3389/fpsyg.2017.00300. Abstract: Functional flexibility, as manifest in the use of any word or sentence to
express different affective valences on different occasions, is required in linguistic
communication and can be said to be an infrastructural property of language. Early
infant vocalizations (protophones), believed to be precursors to speech, occur in
the first month and are functionally different from non-speech-like signals (e.g.,
cries and laughs). Oller et al. (2013) showed that infants by 3 months used three
different protophone types with a full range of affect as manifest in facial expression,
from positive to neutral to negative. These differences in affect were also shown
to correspond to different illocutionary functions, unlike fixed signals, or vegetative
sounds, which showed functional rigidity. The present study investigated whether infants
show functional flexibility in protophones even earlier than the ages studied by Oller
et al. (2013). Data were obtained from 6 infants across the first 3 months. Results
showed that as early as the first month, infant protophones were already accompanied
by variable facial affect valences and continued to be affectively flexible at the
later ages. The present study thus documents the very early emergence of an infrastructural
property of human communication.
Yoo, H., Bidelman, G., Buder, E. H., van Mersbergen, M., Oller, D. K. (2017). Differentiating
infant cry from non-cry vocalizations based on perception of negativity and acoustic
features. The Journal of the Acoustical Society of America. 141. 3748-3749. Abstract: This study seeks to determine how human listeners discriminate cry vs. non-cry
sounds by investigating acoustic factors that may contribute to the perception of
negativity in infant vocalizations (e.g., cry, whine, and vowel-like sounds). The
assumption is that identification of cry is self-evident; therefore, there has been
no attempt to systematically differentiate cry from non-cry vocalizations. Twelve
exemplars each of cry, whine, and vowel-like sound segments (36 total) were selected
from archival audio recordings of infant vocalizations. Categories were selected from
expert-judged audio signals of vocal development. Adult listeners identified each
utterance as either cry, whine, or vowel-like sound as quickly and accurately as possible.
They also judged the extent of negativity of each utterance. Acoustic features of
each utterance were analyzed in association with the categories and degrees of negativity.
Results suggest a continuum of negativity from cries (most negative) to vowel-like
sounds (least negative), and that acoustic variables are gradated across the negativity
continuum. However, preliminary results suggest that peak F0, peak RMS, and spectral
slope best differentiate the categories.
Franklin, B., Warlaumont, A. S., Messinger, D. S., Bene, E., Nathani Iyer, S., Lee,
C-C., Lambert, B., Oller, D. K. (2014). Effects of Parental Interaction on Infant
Vocalization Rate, Variability and Vocal Type. Language Learning and Development.
10(3):279–296. Abstract: Examination of infant vocalization patterns across interactive and noninteractive
contexts may facilitate better understanding of early communication development. In
the current study, with 24 infant-parent dyads, infant volubility increased significantly
when parent interaction ceased (presenting a “still face,” or SF) after a period of
normal interaction (“face-to-face,” or FF). Infant volubility continued at the higher
rate than in FF when the parent re-engaged (“reunion,” or RE). Additionally, during
SF, the variability in volubility across infants decreased, suggesting the infants
adopted relatively similar rates of vocalization to re-engage the parent. The pattern
of increasing volubility in SF was seen across all of the most common speech-like
vocal types of the first half-year of life (e.g., full vowels, quasivowels, squeals,
growls). Parent and infant volubility levels were not significantly correlated. The
findings suggest that by six months of age infants have learned that their vocalizations
have social value and that changes in volubility can affect parental engagement.
Studies of vocal development in infants with or at risk for disorders (autism, premature
birth, deafness, Down syndrome, Fragile X, low socio-economic status)
Oller, D. K., & Eilers, R. E. (1988). The role of audition in infant babbling. Child
Development, 59, 441 449. Abstract: The traditional belief that audition plays only a minor role in infant vocal
development depends upon evidence that deaf infants produce the same kinds of babbling
sounds as hearing infants. Evidence in support of this position has been very limited.
A more extensive comparison of vocal development in deaf and hearing infants indicates
that the traditional belief is in error. Well-formed syllable production is established
in the first 10 months of life by hearing infants but not by deaf infants, indicating
that audition plays an important role in vocal development. The difference between
babbling in the deaf and hearing is apparent if infant vocal sounds are observed from
a metaphonological perspective, a view that takes account of the articulatory/acoustic
patterns of speech sounds in all mature spoken languages.
Eilers, R. E., & Oller, D. K. (1994). Infant vocalizations and the early diagnosis
of severe hard of hearing. Journal of Pediatrics, 124, 199-203. Abstract: To determine whether late onset of canonical babbling could be used as a
criterion to determine risk of hard of hearing, we obtained vocalization samples longitudinally
from 94 infants with normal hearing and 37 infants with severe to profound hard of
hearing. Parents were instructed to report the onset of canonical babbling (the production
of well-formed syllables such as "da," "na," "bee," "yaya"). Verification that the
infants were producing canonical syllables was collected in laboratory audio recordings.
Infants with normal hearing produced canonical vocalizations before 11 months of age
(range, 3 to 10 months; mode, 7 months); infants who were deaf failed to produce canonical
syllables until 11 months of age or older, often well into the third year of life
(range, 11 to 49 months; mode, 24 months). The correlation between age at onset of
the canonical stage and age at auditory amplification was 0.68, indicating that early
identification and fitting of hearing aids is of significant benefit to infants learning
language. The fact that there is no overlap in the distribution of the onset of canonical
babbling between infants with normal hearing and infants with hard of hearing means
that the failure of otherwise healthy infants to produce canonical syllables before
11 months of age should be considered a serious risk factor for hard of hearing and,
when observed, should result in immediate referral for audiologic evaluation.
Belardi, K., Watson, L. R., Faldowski, R. A., Hazlett, H., Crais, E. R., Baranek,
G. T., McComish, C., Patten, E., Oller, D. K. (2017). A retrospective video analysis
of canonical babbling and volubility in infants with Fragile-X syndrome at 9-12 months
of age. Journal of Autism and Developmental Disorders, 47(4), 1193-1206. doi: 10.1007/s10803-017-3033-4.
Abstract: An infant’s vocal capacity develops significantly during the first year
of life. Research suggests early measures of pre-speech development, such as canonical
babbling and volubility, can differentiate typical versus disordered development.
This study offers a new contribution by comparing early vocal development in 10 infants
with Fragile X syndrome and 14 with typical development. Results suggest infants with
Fragile X syndrome produce fewer syllables and have significantly lower canonical
babbling ratios compared to infants who are typically developing. Furthermore, the
particular measures of babbling were strong predictors of group membership, adding
evidence regarding the possible utility of these markers in early identification.
Patten, E., Belardi, K., Baranek, G., Oller, D. K. (2014). Vocal patterns in infants
with Autism Spectrum Disorder: Canonical babbling status and vocalization frequency.
Journal of Autism and Developmental Disorders, 44(10), 2413–2428. doi:10.1007/s10803-014-2047-4.
Abstract: Canonical babbling is a critical milestone for speech development and is
usually well in place by 10 months. The possibility that infants with autism spectrum
disorder (ASD) show late onset of canonical babbling has so far eluded evaluation.
Rate of vocalization or "volubility" has also been suggested as possibly aberrant
in infants with ASD. We conducted a retrospective video study examining vocalizations
of 37 infants at 9-12 and 15-18 months. Twenty-three of the 37 infants were later
diagnosed with ASD and indeed produced low rates of canonical babbling and low volubility
by comparison with the 14 typically developing infants. The study thus supports suggestions
that very early vocal patterns may prove to be a useful component of early screening
and diagnosis of ASD.
Multicultural studies of vocal development
Lee, C-C., Jhang, Y., Chen, L., Relyea, G., Oller, D. K. (2016). Subtlety of ambient-language
effects in babbling: A study of English- and Chinese-speaking infants at 8, 10, and
12 months. Language Learning and Development. DOI: 10.1080/15475441.2016.1180983.
Abstract: Prior research on ambient-language effects in babbling has often suggested
infants produce language-specific phonological features within the first year. These
results have been questioned in research failing to find such effects and challenging
the positive findings on methodological grounds. We studied English- and Chinese-learning
infants at 8, 10, and 12 months and found listeners could not detect ambient-language
effects in the vast majority of infant utterances, but only in items deemed to be
words or to contain canonical syllables that may have made them sound like words with
language-specific shapes. Thus, the present research suggests the earliest ambient-language
effects may be found in emerging lexical items or in utterances influenced by language-specific
features of lexical items. Even the ambient-language effects for infant canonical
syllables and words were very small compared with ambient-language effects for meaningless
but phonotactically well-formed syllable sequences spoken by adult native speakers
of English and Chinese.
Farran, L. K., Lee, C-C., Yoo, H., Oller, D. K. (2016). Cross-cultural register differences
in infant-directed speech: An initial study. PLoS ONE. 11(3). e0151518. doi:10.1371/journal.pone.0151518.
Abstract: Infant-directed speech (IDS) provides an environment that appears to play
a significant role in the origins of language in the human infant. Differences have
been reported in the use of IDS across cultures, suggesting different styles of infant
language-learning. Importantly, both cross-cultural and intra-cultural research suggest
there may be a positive relationship between the use of IDS and rates of language
development, underscoring the need to investigate cultural differences more deeply.
The majority of studies, however, have conceptualized IDS monolithically, granting
little attention to a potentially key distinction in how IDS manifests across cultures
during the first two years. This study examines and quantifies for the first time
differences within IDS in the use of baby register (IDS/BR), an acoustically identifiable
type of IDS that includes features such as high pitch, long duration, and smooth intonation
(the register that is usually assumed to occur in IDS), and adult register (IDS/AR),
the type of IDS that does not include such features and thus sounds as if it could
have been addressed to an adult. We studied IDS across 19 American and 19 Lebanese
mother-infant dyads, with particular focus on the differential use of registers within
IDS as mothers interacted with their infants ages 0–24 months. Our results showed
considerable usage of IDS/AR (>30% of utterances) and a tendency for Lebanese mothers
to use more IDS than American mothers. Implications for future research on IDS and
its role in elucidating how language evolves across cultures are explored.
Automated computational analysis of infant vocal development and vocal disorders
Oller, D. K., Niyogi, P., S. Gray, J. A. Richards, J. Gilkerson, D. Xu, U. Yapanel,
S. F. Warren (2010). Automated Vocal Analysis of Naturalistic Recordings from Children
with Autism, Language Delay and Typical Development. Proceedings of the National Academy
of Sciences, 107, 30, 13354-13359. PMCID: PMC2922144. Abstract: For generations the study of vocal development and its role in language
has been conducted laboriously, with human transcribers and analysts coding and taking
measurements from small recorded samples. Our research illustrates a method to obtain
measures of early speech development through automated analysis of massive quantities
of day-long audio recordings collected naturalistically in children's homes. A primary
goal is to provide insights into the development of infant control over infrastructural
characteristics of speech through large-scale statistical analysis of strategically
selected acoustic parameters. In pursuit of this goal we have discovered that the
first automated approach we implemented is not only able to track children's development
on acoustic parameters known to play key roles in speech, but also is able to differentiate
vocalizations from typically developing children and children with autism or language
delay. The method is totally automated, with no human intervention, allowing efficient
sampling and analysis at unprecedented scales. The work shows the potential to fundamentally
enhance research in vocal development and to add a fully objective measure to the
battery used to detect speech-related disorders in early childhood. Thus, automated
analysis should soon be able to contribute to screening and diagnosis procedures for
early disorders, and more generally, the findings suggest fundamental methods for
the study of language in natural environments.
Warren, S. F., Gilkerson, J., Richards, J., Oller, D. K., Xu, D., Yapanel, U. (2010).
What automated vocal analysis reveals about the language learning environment of young
children with autism. Journal of Autism and Developmental Disorders, 40, 555-569.
Abstract: The study compared the vocal production and language learning environments
of 26 young children with autism spectrum disorder (ASD) to 78 typically developing
children using measures derived from automated vocal analysis. A digital language
processor and audio-processing algorithms measured the amount of adult words to children
and the amount of vocalizations they produced during 12-h recording periods in their
natural environments. The results indicated significant differences between typically
developing children and children with ASD in the characteristics of conversations,
the number of conversational turns, and in child vocalizations that correlated with
parent measures of various child characteristics. Automated measurement of the language
learning environment of young children with ASD reveals important differences from
the environments experienced by typically developing children.
Woynaroski, T. G., Oller, D. K., Kaysili, B. K., Yoder, P. (2016). The stability and
validity of automated vocal analysis in preverbal preschoolers with autism spectrum
disorder: Automated Vocal Analysis in ASD. Autism Research. DOI: 10.1002/aur.1667
DOI: 10.1002/aur.1667. Abstract: Theory and research suggest that vocal development predicts "useful speech"
in preschoolers with autism spectrum disorder (ASD), but conventional methods for
measurement of vocal development are costly and time consuming. This longitudinal
correlational study examines the reliability and validity of several automated indices
of vocalization development relative to an index derived from human coded, conventional
communication samples in a sample of preverbal preschoolers with ASD. Automated indices
of vocal development were derived using software that is presently "in development"
and/or only available for research purposes and using commercially available Language
ENvironment Analysis (LENA) software. Indices of vocal development that could be derived
using the software available for research purposes: (a) were highly stable with a
single day-long audio recording, (b) predicted future spoken vocabulary to a degree
that was nonsignificantly different from the index derived from conventional communication
samples, and (c) continued to predict future spoken vocabulary even after controlling
for concurrent vocabulary in our sample. The score derived from standard LENA software
was similarly stable, but was not significantly correlated with future spoken vocabulary.
Findings suggest that automated vocal analysis is a valid and reliable alternative
to time intensive and expensive conventional communication samples for measurement
of vocal development of preverbal preschoolers with ASD in research and clinical practice.
Warlaumont, A. S., Richards, J. A., Gilkerson, J. & Oller, D. K. (2014). A Social
Feedback Loop for Speech Development and Its Reduction in Autism. Psychological Science,
25: 1314-1324. DOI: 10.1177/0956797614531023 NIHMS577758. Abstract: We analyzed the microstructure of child-adult interaction during naturalistic,
daylong, automatically labeled audio recordings (13,836 hr total) of children (8-
to 48-month-olds) with and without autism. We found that an adult was more likely
to respond when the child's vocalization was speech related rather than not speech
related. In turn, a child's vocalization was more likely to be speech related if the
child's previous speech-related vocalization had received an immediate adult response
rather than no response. Taken together, these results are consistent with the idea
that there is a social feedback loop between child and caregiver that promotes speech
development. Although this feedback loop applies in both typical development and autism,
children with autism produced proportionally fewer speech-related vocalizations, and
the responses they received were less contingent on whether their vocalizations were
speech related. We argue that such differences will diminish the strength of the social
feedback loop and have cascading effects on speech development over time. Differences
related to socioeconomic status are also reported.
Abney, D. H., Warlaumont, A. S., Oller, D. K., Wallot, S., & Kello, C. T. (2016).
Multiple Coordination Patterns in Infant and Adult Vocalizations. Infancy, 9, 1. doi:10.1111/infa.12165.
Abstract: The study of vocal coordination between infants and adults has led to important
insights into the development of social, cognitive, emotional, and linguistic abilities.
We used an automatic system to identify vocalizations produced by infants and adults
over the course of the day for fifteen infants studied longitudinally during the first
2 years of life. We measured three different types of vocal coordination: coincidence-based,
rate-based, and cluster-based. Coincidence-based coordination and rate-based coordination
are established measures in the developmental literature. Cluster-based coordination
is new and measures the strength of matching in the degree to which vocalization events
occur in hierarchically nested clusters. We investigated whether various coordination
patterns differ as a function of vocalization type, whether different coordination
patterns provide unique information about the dynamics of vocal interaction, and how
the various coordination patterns each relate to infant age. All vocal coordination
patterns displayed greater coordination for infant speech-related vocalizations, adults
adapted the hierarchical clustering of their vocalizations to match that of infants,
and each of the three coordination patterns had unique associations with infant age.
Altogether, our results indicate that vocal coordination between infants and adults
is multifaceted, suggesting a complex relationship between vocal coordination and
the development of vocal communication.
Gilkerson, J., Richards, J.A., Warren, S. F., Greenwood, C. R., Oller, D. K., Montgomery,
J. K., Hansen, J. H. L., Xu, D. & Paul, T. D. (2017). Mapping the early language environment
using all-day recordings and automated analysis. American Journal of Speech Language
Pathology. doi:10.1044/2016. Abstract: Purpose: This research provided a first-generation standardization of automated
language environment estimates, validated these estimates against standard language
assessments, and extended on previous research reporting language behavior differences
across socioeconomic groups. Method: Typically developing children between 2 to 48
months of age completed monthly, daylong recordings in their natural language environments
over a span of approximately 6-38 months. The resulting data set contained 3,213 12-hr
recordings automatically analyzed by using the Language Environment Analysis (LENA)
System to generate estimates of (a) the number of adult words in the child's environment,
(b) the amount of caregiver-child interaction, and (c) the frequency of child vocal
output. Results: Child vocalization frequency and turn-taking increased with age,
whereas adult word counts were age independent after early infancy. Child vocalization
and conversational turn estimates predicted 7%-16% of the variance observed in child
language assessment scores. Lower socioeconomic status (SES) children produced fewer
vocalizations, engaged in fewer adult-child interactions, and were exposed to fewer
daily adult words compared with their higher socioeconomic status peers, but within-group
variability was high. Conclusions: The results offer new insight into the landscape
of the early language environment, with clinical implications for identification of
children at-risk for impoverished language environments.
Warlaumont, A. S., Oller, D. K., Buder, E. H., & Westermann, G. (2013). Prespeech
motor learning in a neural network using reinforcement. Neural Networks, 38, 64–75.
PMCID: PMC3541464. doi:10.1016.j.neunet.2012.11.012. Abstract: Vocal motor development in infancy provides a crucial foundation for language
development. Some significant early accomplishments include learning to control the
process of phonation (the production of sound at the larynx) and learning to produce
the sounds of one's language. Previous work has shown that social reinforcement shapes
the kinds of vocalizations infants produce. We present a neural network model that
provides an account of how vocal learning may be guided by reinforcement. The model
consists of a self-organizing map that outputs to muscles of a realistic vocalization
synthesizer. Vocalizations are spontaneously produced by the network. If a vocalization
meets certain acoustic criteria, it is reinforced, and the weights are updated to
make similar muscle activations increasingly likely to recur. We ran simulations of
the model under various reinforcement criteria and tested the types of vocalizations
it produced after learning in the different conditions. When reinforcement was contingent
on the production of phonated (i.e. voiced) sounds, the network's post-learning productions
were almost always phonated, whereas when reinforcement was not contingent on phonation,
the network's post-learning productions were almost always not phonated. When reinforcement
was contingent on both phonation and proximity to English vowels as opposed to Korean
vowels, the model's post-learning productions were more likely to resemble the English
vowels and vice versa.
