Final answer:
Piaget's test with children arranging sticks was meant to assess seriation, a cognitive ability that develops in the concrete operational stage, indicating logical thinking about the physical world. This stage also includes critical milestones, like understanding conservation, where invariable properties of objects are recognized despite appearance changes.
Step-by-step explanation:
To test for cognitive development, Piaget asked children to arrange sticks of different lengths from shortest to longest. This particular test relates to a concept known as seriation, which is the ability to sort objects or situations according to any characteristic, such as size, color, shape, or type. This skill is typically developed during Piaget's third stage of cognitive development, the concrete operational stage, which occurs from about 7 to 11 years old.
During the concrete operational stage, children begin to think more logically about the physical world. Piaget designed experiments, such as the conservation of number and quantity, to measure when children attain the understanding that certain properties of objects remain the same despite changes in the object's arrangement or appearance. A well-known example of this is the observation that the volume of water remains the same when transferred between containers of different shapes.
In Piaget's framework, mastering the concept of conservation is a key milestone. The understanding of conservation signifies that a child has developed the ability to recognize that two equal quantities remain equal even after one of them is rearranged or undergoes some type of transformation that changes its appearance but not its fundamental properties.