I'm not saying that this research is rendered obvious by Piaget's work. Nor did I say that the age at which children make certain transitions is fixed in stone. Nor would I try to imply that Piaget discovered everything about the subject. Nor did I try to indicate that there are not gifted children.
However I stand by my claim that Piaget's work provides a framework to understand why a young child's ability at one task (sorting lines by length and objects by weight) is indicative of a much broader range of cognitive skills. Furthermore the fact that cognitive abilities go through periods of rapid advance over a broad range of areas makes it less surprising to me that you see fairly large shifts in where children stand relative to each other in ability.
However I stand by my claim that Piaget's work provides a framework to understand why a young child's ability at one task (sorting lines by length and objects by weight) is indicative of a much broader range of cognitive skills. Furthermore the fact that cognitive abilities go through periods of rapid advance over a broad range of areas makes it less surprising to me that you see fairly large shifts in where children stand relative to each other in ability.