During a study of cognitive development, a researcher demonstrates that two identical balls of clay contain the same amount of material. The researcher then rolls one of the balls into a long, thin cylinder. A child is asked if the two pieces still have the same amount of clay, and they correctly answer that they do.
Identify the cognitive concept demonstrated by the child's response and explain what is meant by this concept.
59 exam-style questions on AQA A Level Psychology Piaget's theory of cognitive development. Each one has a worked solution and a mark scheme showing where the marks go.