Final answer:
Object permanence generally appears around 8 months, marking a developmental stage in a child's cognitive growth where they understand that objects continue to exist even when not visible.
Step-by-step explanation:
The statement that object permanence generally appears about eight months is True. Object permanence is a cognitive milestone that refers to a child's understanding that objects continue to exist even if they cannot be seen or heard. This milestone typically develops between 5 and 8 months old as delineated by early developmental psychology, particularly within the research of Jean Piaget. Infants at this stage begin to demonstrate awareness of objects' continuity by looking for hidden objects, which reflects their ability to form a mental representation of the object.