Explain the stages of Piaget's theory of cognitive development (4 marks).

Piaget's theory of cognitive development has four main stages of mental development in children. It focuses on how children acquire knowledge throughout their childhood, in a stage-like fashion, as opposed to gradual development. He suggests that this may be due to a combination of biological maturation and environment interaction. Piaget suggests the first stage is from birth to 2 years of age, and this is the sensorimotor stage. The main achievement in this stage is the idea of object permanence. This means that the infant understands that an object still exists despite it not being visible to them. The second stage of development is the preoperational stage, from 2-7 years of age. In this stage of development the child can understand concepts symbolically. Following this is the concrete operational stage, from 7-11 years of age. At this stage, logical thought begins, meaning that they can have internal thoughts about situations rather than having to work it out physically in the real world. They also begin to become better at conservation tasks in this stage. The final stage, the formal operational stage, is from 11 years plus. This stage lasts into adulthood, and marks the point in development at which children can think about concepts abstractly and test different hypotheses.