Knowledge-Building Through Categorization: Boosting Children's Vocabulary and Content Knowledge in a Shared Book Reading Program

Research Findings: The purpose of this study was to examine the effects of categorization in shared book reading as a mechanism for developing preschoolers' topical knowledge in life science. Prekindergarten children from 4 schools and 23 classrooms in a large metropolitan area were randomly selected into treatment (N = 12 classrooms) and control groups (N = 11 classrooms). In the 4-month trial, children in the treatment group were introduced to science topics that were structured to promote categorization and concepts through shared book reading of text-sets that included narrative nonfictional and information books, while the control group received the same materials without lessons on categorization. Pre- and posttests examined child outcomes in vocabulary, categorical properties, content and inferential reasoning. Results indicated that children in the treatment group learned significantly more words and made more explicit inferences than the control group. Policy and practice: Together, it highlights the potential use of categorization in knowledge-building and schema development.