Child Motivation, Shared Book Reading, and Vocabulary Development: A Growth Mixture Modeling Approach Christine Meng Curriculum and Instruction University of Wisconsin-Madison INTRODUCTION Head Start children have been shown to have a higher rate of difficulties in literacy and language development due to poverty. The home environment, in particular shared book reading, may be related to children’s language development. While the extant research has link shared book reading with children’s vocabulary development, the nature of the association is still not clear, particularly with respect to the pathways through which shared book reading and children’s vocabulary development are linked. Prior research has identified parents’ reading beliefs (Cottone, 2012), teachers’ curriculum goals (Massetti & Bracken, 2010), and mothers’ education level (Korat, 2009) as the mechanisms that explain this association. However, what is less understood is the role of child motivation. Studies show that children who show greater persistence and more attention tend to have better academic performance (Berhenke, Miller, Brown, Seifer, & Dickstein, 2011; Skinner & Belmont, 1993). These studies demonstrate that children who are more motivated tend to pursue more learning opportunities, resulting in greater academic performance. To examine child motivation, shared book reading, and the trajectories of vocabulary development among children of low-income families, this study used a nationally representative sample of Head Start children, with the emphasis on child motivation as the moderator. Specifically, this study examined (1) direct effects of child motivation and shared book reading on the trajectories of vocabulary development, and (2) child motivation as a factor that moderated the effect of shared book reading on the trajectories of vocabulary development. RESULTS Two classes of vocabulary development emerged from the results of growth mixture modeling: a decrease-increase class and a decrease-only class. Approximately 66% of Head Start children belonged to the decrease-increase class. Approximately 34% of Head Start children belonged to the decrease-only class. The results for the first research question showed that shared book reading, competence motivation, and persistence had direct effect on the trajectories of vocabulary development. For the decrease-increase class, shared book reading, competence motivation, and persistence had positive impact on the vocabulary scores in the first kindergarten year and the vocabulary growth and acceleration over time. For the decrease-only class, competence motivation was the only factor that had positive impact on the vocabulary growth. The results for the second research question showed that the effect of shared book reading on Head Start children’s vocabulary development depended on the children’s learning behavior. Higher levels of shared book reading predicted higher levels of vocabulary growth when the children had higher levels of learning behavior. Children with higher levels of learning behavior scored higher on the vocabulary test than those with lower levels of learning behavior. In the context of shared book reading, parents may choose interesting reading materials to increase children’s interest in print, thereby increasing children’s positive attitude and confidence toward reading. This finding appears to suggest a potential bidirectional relationship between shared book reading and children’s learning behavior. Shared book reading can increase children’s interest and motivation to read, which in turn may engage in more shared book reading activities. Future research needs to consider the long-term bidirectional process between shared book reading and children’s learning behavior to understand whether shared book reading and children’s learning behavior reciprocally influence each other. DISCUSSION The purpose of this study was to understand (1) the direct effect of shared book reading and children’s learning motivation on Head Start children’s vocabulary trajectories; and (2) the indirect, moderating factor of children’s learning motivation on the effect of shared book reading on Head Start children’s vocabulary trajectories. The results showed heterogeneous vocabulary trajectories in this population. Head Start children who demonstrated vocabulary growth were those who had parents who frequently read to them and showed higher levels of motivation to learn. On the other hand, Head Start children whose vocabulary skills remained low throughout the four measurement occasions were children who showed competence motivation. It appears there is a double dosage effect for the combination of shared book reading and children’s competence motivation. Higher levels of shared book reading predicted higher levels of vocabulary growth when the children had higher levels of competence motivation. Children with higher levels of competence motivation scored higher on the vocabulary test than those with lower levels of learning behavior. The moderating role of children’s learning behavior on vocabulary growth may be due to the extent to which the parents structure the home environment to provide their children literacy experience. A structured family literacy environment can facilitate children’s positive perception of their reading competence via parent involvement and autonomy support. Parents who are involved in their children’s education are likely to attend the parent-teacher conference, help their children with school homework, talk to the teacher about what books they should read to their children at home, and so forth. Similarly, parents’ autonomy support can increase young children’s vocabulary development through scaffolding to support the children’s reading competence. The reason for parents to provide support and scaffold is to help young children regulate their motivation and engagement with print. Over time the children will be able to internalize these external regulations so as to be intrinsically motivated to read. Provided that two developmental trajectories of vocabulary are identified, future research needs to examine how the interaction between child motivation and shared book reading plays out for Head Start children with different developmental trajectories. The results have implications for shared book reading interventions and educators. Educators and parents need to be aware that passively reading to their children may not be the best way to motivate the children to read. Engaging the children in the story and providing feedback to scaffold children’s reading competence may be more likely to facilitate children’s comprehension and vocabulary growth. DATASET The data used for this project came from the Head Start Family and Child Experiences Survey (FACES—2003 Cohort). The FACES is a national longitudinal study that examines the cognitive, emotional, social, and physical development of the Head Start children in the United States. The FACES study also includes variables that examine the characteristics and well-being of families, the observed quality of Head Start classrooms, and the characteristics and opinions of Head Start teachers and other program staff. The FACES included a sample of 1,778 children who were three and four years old and their parents in a stratified national probability sample of 43 Head Start programs. The sample was stratified by three variables: region of the country, urbanicity, and percentage of minority families in the program. The following Head Start programs were excluded: Migrant and Seasonal Head Start programs, American Indian/Alaska Native Head Start programs, Early Head Start programs, programs in the United States territories, and programs that do not serve children directly. REFERENCES Berhenke, A., Miller, A. L., Brown, E., Seifer, R., & Dickstein, S. (2011). Observed emotional and behavioral indicators of motivation predict school readiness in Head Start graduates. Early Childhood Research Quarterly, 26, doi: /j.ecresq Cottone, E. A. (2012). Preschoolers’ emergent literacy skills: The mediating role of maternal reading beliefs. Early Education and Development, 23, doi: / Korat, O. (2009). The effect of maternal teaching talk on children's emergent literacy as a function of type of activity and maternal education level. Journal of Applied Developmental Psychology, 30, doi: /j.appdev Massetti, G. M., & Bracken, S. S. (2010). Classroom academic and social context: Relationships among emergent literacy, behavioural functioning and teacher curriculum goals in kindergarten. Early Child Development and Care, 180, doi: / Skinner, E. A., & Belmont, M. J. (1993). Motivation in the classroom: Reciprocal effects of teacher behavior and student engagement across the school year. Journal of Educational Psychology, 85, doi: / Data Sources *The Office of Planning, Research and Evaluation, the Administration for Children and Families, the U.S. Department of Health and Human Services *Child Care & Early Education Research Connections ABSTRACT Based on the sociocultural theory and the expectancy-value theory, this study (1) examined direct effects of shared book reading and child motivation on the vocabulary trajectories, and (2) whether child motivation moderated the effect of shared book reading on the vocabulary trajectories. The growth mixture modeling was performed to address the research questions with a nationally representative sample of Head Start children. Two latent classes of vocabulary trajectories were found. Shared book reading, competence motivation, and persistence had direct effects on vocabulary growth. Motivation emerged as a significant moderator—highly motivated children had more growth in vocabulary regardless of the levels of shared book reading. However, higher levels of shared book reading were more important for less motivated children. METHOD SAMPLE The sample included a total of 2,612 children and their parents or the primary caregivers (mean annual family income = $16,457.75, SD = 12, ). The family structure was diverse (48% two-parent household, 47% mother-only single-parent household, 2% father-only single-parent household, and 3% had neither a mother nor a father as the head of the household). The children’s mean age at program entry was four years old (49% male, 51% female; 29% Caucasian, 31% African American, 33% Hispanic, 7% others). The mothers’ mean age in fall 2003 was years old (SD = 6.24) with 67% having more than high school education. The fathers’ mean age in fall 2003 was years old (SD = 7.38) with 64% having more than high school education. The parents had diverse race and ethnicity backgrounds (mothers: 34% Caucasian, 30% African American, 32% Hispanics, and 4% others; fathers: 30% Caucasian, 34% African American, 31% Hispanics, 5% others). MEASURES Children’s vocabulary was measured by the Peabody Picture Vocabulary Test (PPVT-III) (Dunn & Dunn, 1997). Shared book reading was measured by parental report of reading to the child in the past week on a scale of 1 (not at all in last week) to 4 (every day). Children’s competence motivation and persistence were measured by the Preschool Learning Behavior Scale (McDermott, Green, Francis, & Stott, 2000). ANALYSIS RQ1 was examined by using growth mixture modeling to determine the number of classes of vocabulary development. RQ2 was examined by using latent growth curve analysis to regress the predictors on the three latent growth factors (intercept, linear slope, and quadratic slope) while controlling for the amount of reading materials at home, child age, child gender, child disability status, family annual income, family structure, mother education, and child ethnicity.