Answering this question “Counts” as a discussion response.
Many researchers have conducted studies in the years since Piaget’s work, with some using different methods and finding that children had abilities at even younger ages than thought by Piaget.
For example, Renee Baillargeon used habituation studies to demonstrate that object permanence may develop as young as 3 ½ months whereas Piaget believed this started at 8 months of age. In his studies he hid an object under a blanket, and required lifting up the blanket to look for the object (which obviously very young babies would not have the motor skills to do).
Here is a video of some of Dr. Baillargeon’s work where she examines infants’ looking time to understand whether infants thought the object that was out of sight still existed:
What are the implications of this work for Piaget’s theory? What does it tell us about the importance of methodology in studying children’s abilities?
Baillargeon, R. (2004). Infants’ reasoning about hidden objects: Evidence for event-general and event-specific expectations. Developmental Science, 7, 391–424.