Final answer:
Research demonstrating that young infants reach for objects in the dark is evidence of their understanding of object permanence.
Step-by-step explanation:
Research demonstrating that young infants reach for objects in the dark is evidence of their understanding of object permanence. Object permanence is the concept that even if something is out of sight, it still exists. Piaget's studies showed that infants who had developed object permanence would reach for a hidden toy, indicating that they knew it still existed.