We have been involved in a longitudinal research project on language development since 2002 and it is ongoing with current support (from the National Institute of Child Health and Human Development) through 2012.
This project is designed to provide insights into human development and the development of language in particular. We focus on linguistic and gestural inputs and their consequences for child language and gesture as both play out over time in typically developing and brain injured children. Our study reveals a great deal about caregiver and child language, how each evolves over time, and how the interactions between caregivers and children influence development.
See also
This announcement of our NIH grant provides a concise overview of our project’s scope and objectives.
Acquiring the ability to communicate using natural language and symbolic gestures is a uniquely human capacity that underlies the exchange of information among people. There is as yet no consensus concerning how susceptible this process is to environmental and biological variation. Our longitudinal study focuses on this issue, exploring the extent and the limits of the language-learning process.
To examine language growth in the face of environmental variation we have observed 60 children, selected to represent the demographic range of the Chicago area, between the ages of 14 and 58 mos. and have continued to follow them as they enter school and learn to read. Assessments have been made of child and parent spontaneous speech, along with narrative and reading skills from 5 to 10 years.
Using this data, growth curves will be constructed for each child to track language and reading development across time, and to examine children’s linguistic and reading progress in the later years (5-10 yrs.) in relation to their developmental trajectory during the early years (14-58 mos.).
To explore language growth in the face of biological variation 40 children with unilateral brain injury who were observed from 14 to 58 mos. are being followed from 5 to 10 years with an eye toward determining whether environmental variation plays the same role in predicting their language and reading growth as it does in children who have not suffered brain injury.
Along with traditional measures, the gesturing of our child subjects is being examined to determine whether children who are delayed in speech relative to their peers use gesture to compensate for those delays.
We are also using fMRI techniques to assess the brain bases underlying linguistic and gestural competence.
Our work builds on five years of longitudinal data in a diverse sample, and thus offers a unique opportunity to explore the impact that early language learning has on the oral and written skills that children develop once schooling has begun. This data has the potential to shed light on the factors that contribute to the gap between children from high vs. low socio-economic groups on the first day of school, and may even point to ways of shrinking that gap.
Our major concern is with growth, and with the possibility that variations in caregiver speech and gesture may affect the course and outcomes of language development in the child. The study began in 2002 when the target children were 14 months old and is ongoing with current support (from the National Institute of Child Health and Human Development) though 2012, when all of the children will have completed 4th grade, and some will have completed 5th grade, depending on when their birthdays and time of school entry.
Two groups of families were enrolled at the start of this longitudinal study: (1) a group of 64 families with a child who was developing typically at entry into the study (TD group) and (2) a group of 42 families with a child who had suffered a unilateral brain lesion in the pre- or peri-natal period (PL group).
Families of the TD children were recruited from the greater Chicago area through a direct mailing to roughly 5,000 families or through an advertisement in a free, monthly parent magazine. We asked parents who responded to participate in a phone interview in which we gathered demographic information on their children and family. We then selected subjects who matched as closely as possible the ethnic/racial makeup and family income for the Chicago area as reported in the 2000 U.S. Census. Sixty-four families completed at least four visits, and Table 1 shows the number of children in different income and ethnic/racial groups at entry into the study. In this sample, there are 31 girls and 33 boys, and 34 are first born children. All families participating in the study are monolingual English speakers.
Families of children with PL were recruited through brochures in Chicago-area pediatric neurology and rehabilitation clinics and through advertisements to members of parent support groups for families with children who have a brain injury. Children were enrolled in the study if brain imaging (MRI) results confirmed the presence of a unilateral injury of pre- or perinatal origin. Children with congenital malformation and bleeds associated with prematurity (under 36 weeks gestation) were excluded. On the basis of MRI scans, lesions were categorized in terms of laterality (left, right), size (small, medium, large) and lesion type (periventricular (PV) lesion or cerebrovascular (CV) lesion). Small lesions affected only one lobe or minimally affected subcortical regions. Medium lesions extended into more than one lobe or subcortical region. Large lesions affected three or four lobes, often involved the thalamus and other subcortical regions, and were typically cerebrovascular infarcts. Regarding lesion type, CV lesions are infarcts of the middle cerebral arty territory and tend to affect the infereior frontal and/or superior temporal regions. PV lesions are primarily subcortical and involve white matter tracts, the thalamus, basal ganglia and/or the medial temporal lobe. Because of the relative scarcity of children with this type of injury (roughly 1 in 4,000), families were not excluded based on demographic characteristics. In addition, PL children were enrolled in the study at various ages (from 14 - 54 months). Forty-two families completed at least four visits. In this sample, there are 25 girls and 27 boys, 13 with right-sided brain injury, and 29 with left-sided injury. Different subgroups of the brain injured sample were included in various studies depending on whether the child had participated in the study at various ages.
There are two parts to this study: 1) A primarily observational study of the children and their primary caregiver(s) conducted from child age of 14 months to 58 months. 2) A follow-up study of the same children during the early elementary school years (kindergarten – 4th grade) which collects data on the child’s emerging literacy and reading skills, as well as mathematical and spatial skills.
In the pre-school observational study, families are visited in their homes every four months for a total of 12 visits between 14 months and 58 months. The researcher videotapes the interactions of parental caregiver(s) and target child during their ordinary daily activities for a 90-minute period at each visit, interacting minimally with the families. The majority of families have a parent, usually the mother, who self-identified as the primary caregiver for the child. Several families (7 in TD, x in PL) are dual caregiver families, and these visits usually include both the mother and the father interacting with the target child. Other children and family members are sometimes present during these visits, but our video recordings focus on the interaction between the target child and the parental caregiver(s).
In the school-age study, families are visited in their homes at the beginning of every school year (Sept-Oct), the middle of the school year (Jan-Feb), and at the end of the school year (May-June) from kindergarten through 4th grade. At these visits, the researcher interacts one-on-one with the child over a 2-hour period, giving them a number of tasks to complete, as well as spending a period of time (20 minutes) having a spontaneous conversation with the child.
Throughout the study, children and parents were given standardized tests, tasks and questionnaires to complete. For a description of the tasks and questionnaires given at each timepoint, see our Tasks page.
Transcripts are made from collected video recordings of parent/child interaction and researcher/child interaction. Speech and gesture are systematically coded.
The speech utterances for both child and parent are transcribed verbatim using English words (gotta is transcribed as got to) and incorrect grammar is not corrected (where my puppy?). Rules were developed for delineating utterance boundaries, including 1) an utterance is never more than one conversational turn; 2) an utterance is never more than one sentence long; 3) an utterance can be a single word, a phrase, or a sentence and 4) intonational contours (such as raising the voice at the end of a question) indicate the end of an utterance. All child speech and all primary caregiver speech directed to the child is transcribed. In addition, primary caregiver speech to siblings under the age of 13 is transcribed and, if designated as a dual caregiver, the other parent’s child-directed speech is transcribed.
Each gesture made by the child or the parent is marked in the transcript. Gestures are classified into 5 types (McNeill, 1992): deictic (either a point or a hold-up), conventional (e.g., nod, side-to-side shake, shrug), iconic (e.g., flap arms as though flying like a bird, thumb and finger form a circle that resembles a penny), metaphoric (e.g., extending a palm outward to represent putting an idea forward), or beats (e.g., a rhythmic movement that punctuates speech). The form of each gesture is described in terms of the shape of the hand, the type of movement, and the place of articulation. In addition, using non-linguistic context, the first four types of gestures are assigned a meaning (see Goldin-Meadow & Mylander 1984, for a detailed description of how meaning is assigned to gestures). Gesture interpretation in spontaneous conversations is facilitated by the fact that we are familiar with the activities that typically occur during the taping sessions, and by the fact that the parents frequently share their intimate knowledge of the child’s world with us during the taping sessions.
We employ two different reliability measures. The first concerns the reliability of the transcription (inter-transcriber agreement). For at least one out of every five transcripts, a second person transcribes 10% of the utterances. Agreement needs to exceed 90% at the word level and for delineation of utterance boundaries. The second measure concerns the intercoder agreement of particular speech or gesture categories coded. A second person codes a random selection of 10% of the utterances and the proportion of utterances on which the two coders agreed is calculated for each category. Agreement needs to exceed 88% for all categories coded.