Describes the nature and occurrence of knowledge-construction links (KCLs) in 3 6th-grade classrooms that varied in degree of learner centeredness. KCLs are operationalized as prior learning that students bring to their current classroom experiences and include school and nonschool experiences. They are hypothesized to facilitate a knowledge-construction process that values prior learning. (Contains 32 references, 6 tables, and 1 figure.) (GCP)