Despite significant investments over the past decade in the expansion and improvement of preschool programs, too many children, particularly poor children, enter kindergarten behind their peers. Because it is critical that voluntary pre-kindergarten (VPK) classrooms offer educational programs that both address the needs and developmental levels of…

Research Findings: A total of 72 Head Start children (M age = 53.26 months, SD = 5.07) were randomly assigned to 4 conditions. Some were taught the oddity principle (choosing the object that differs from others in a group) and seriation (ordering objects on a dimension and inserting new objects into such orders), which are forms of thinking that…