Developmental or progressive schools adhere to the developmental-interaction approach, believing that children learn through exploration and collaboration. The aim of this method is to allow the children to learn at their own pace through active play and to facilitate constant interaction between emotional and cognitive development. Teachers rarely use workbooks and tests but rely on manipulatives (i.e., blocks, water, sand, paint and puzzles) to teach math and reading skills. Students learn these skills at their own pace. Children are also given plentiful free time where socialization is encouraged.