Conservation Tasks and Reason

Piaget had his own way of assessing brain maturation during this period, using his now-famous "conservation" tasks, try this one out on your tour-to-eight-year-old: fill two identical short, squat glasses with equal volumes of water, and ask your child, "Do the two glasses contain the same amount of water, or does one have more?" Now, pour all the water from one of these 'lasses into a tall, narrow glass, and ask your child the same question. Four-year-olds almost invariably say that the ta...