The document discusses Piaget's preoperational stage of cognitive development, which occurs from ages 2 to 7 and is characterized by symbolic thought, egocentrism, and the inability to understand conservation. Key features include children's limited ability to see perspectives other than their own and their use of symbols in play and language. Critiques of Piaget's theory suggest he underestimated children's abilities and the influence of specific experiences on their cognitive development.