A developmental psychologist recorded the following observations of one child, Leo, over several years.
| Leo's age | Observation |
|---|---|
| 20 months | Leo explores a new rattle by turning it, shaking it and putting it in his mouth. |
| 5 years | Leo uses an empty cardboard tube as a telescope and says that a toy train is sad because it has been left alone. |
| 9 years | Leo says that flattening a ball of modelling clay does not change the amount because it could be made back into a ball. He needs the clay in front of him to reason this out. |
| 14 years | Before carrying out an investigation, Leo lists possible combinations of light and water and plans how to test each combination systematically. |
Describe how the observations show that Leo has moved through Piaget's four invariant stages of cognitive development.
104 exam-style questions on OCR GCSE Psychology 2.2 Theories/Explanations, covering 2.2.1 Piaget's four invariant stages, 2.2.2 Assimilation and accommodation, 2.2.3 Object permanence, animism, egocentrism, 2.2.4 Decentration, reversibility, conservation; criticisms, 2.2.5 Cognitive Development research study: Piaget (1952), 2.2.6 Dweck's fixed and growth mindsets, 2.2.7 Willingham's learning styles and meaning; criticisms, and 2.2.8 Learning research study: Blackwell et al. (2007). Each one has a worked solution and a mark scheme showing where the marks go.