Final answer:
Researchers believe Piaget underestimated cognition in both infancy and early childhood, as current research indicates that infants have a more advanced understanding of object properties and young children develop cognitive abilities earlier than Piaget suggested.
Step-by-step explanation:
Researchers now believe that Jean Piaget underestimated cognition in infancy and underestimated cognition in early childhood. Piaget's theory of cognitive development articulated that infants and young children have a less sophisticated understanding of the world around them, particularly in concepts such as object permanence and the physical properties of objects. However, more recent research has shown that infants possess a more advanced understanding of object permanence and the properties of objects than Piaget originally theorized. Studies demonstrate that infants as young as 3 months old exhibit knowledge about the properties of objects without having direct experience with them, indicating an innate understanding that is more developed than what Piaget proposed. Similarly, young children show signs of cognitive abilities like theory-of-mind earlier than Piaget's stage theory would suggest, indicating that early childhood cognition was also underestimated.