Final answer:
Children see the mind as an active constructor of knowledge during the concrete operational stage, from about 7 to 11 years old, when their thought processes become more logical and organized in dealing with concrete information.
Step-by-step explanation:
Children begin to see the mind as an active constructor of knowledge or processing center during the concrete operational stage of cognitive development, typically from about 7 to 11 years old. According to Jean Piaget, during this stage, children's thought processes become more logical and organized when dealing with concrete information. They start understanding concepts like conservation, which is the idea that even if you change the appearance of something, it remains equal in size, volume, or number as long as nothing is added or removed. This represents an evolution in their cognitive abilities and a shift from perceiving the world in a purely physical and immediate sense to a more structured and logical way of processing information. Prior to the concrete operational stage, in the preoperational stage which lasts from approximately 3 to 7 years of age, preschool-age children show evidence of symbolically thinking and enjoy pretend play, inventing elaborate characters and scenarios. This stage showcases their burgeoning curiosity and their ability to engage in complex play, but their understanding is still not as logical and organized as it will become in subsequent years. By the time they reach the concrete operational stage, they have a more developed sense of logic that allows them to handle more complex ideas such as addition and subtraction and cause-and-effect relationships.