Answer:
3-4 months
Explanation:
Researchers such as Baillargeon have found that infants' perceptual abilities are highly developed much earlier than Jean Piaget proposed. These researchers conclude that infants see objects as bounded, unitary, solid, and separate from their background by 3 - 4 months of age.
Contrary to Piagets theory that suggest that infants show perceptual ability at 8-12 months of age in the sensorimotor stage, researchers such as Baillargeon have reported that infants perceptual abilities are developed as early as 3-4 months of age.