In Piaget's classification of cognitive stages, at what age do children begin to demonstrate seriation?

Children begin to demonstrate seriation during the concrete operational stage, which occurs approximately between the ages of 7 and 11. Seriation is the ability to arrange objects in an order based on a specific characteristic, such as size or color. This cognitive skill reflects a child's developing ability to think logically about concrete events and apply systematic reasoning to organize information.

During the earlier preoperational stage, from ages 2 to 7, children typically engage in symbolic play and struggle with tasks requiring logical reasoning, which includes the ability to sort and arrange objects. As they transition into the concrete operational stage, they become more adept at performing concrete operations, such as seriation, which indicates a significant maturation of their cognitive abilities.

In summary, the demonstration of seriation is a hallmark of the concrete operational stage, emphasizing the children's growing capacity for logical thinking and organization of information in a structured manner.