Final answer:
By the age of two months, an infant may show surprise when a toy duck is placed behind a screen and taken away, but they will not look for it because they have not yet developed object permanence.
Step-by-step explanation:
By the age of two months, an infant may show surprise when a toy duck is placed behind a screen and then taken away. However, the infant will not look for the toy because they have not yet developed object permanence. Object permanence is the understanding that objects continue to exist even when they are out of sight. According to Jean Piaget, infants who have not developed object permanence will appear confused when the toy is hidden and not look for it.