Respuesta :
Answer: Object permanence
Explanation:
As per theory of Piaget, object performance is defined as the phenomena in which infants tend to understand that objects such as toys,teddy bears etc will keep on existing even when they cannot be seen, heard, sensed or touched.
According to the question,Trevor is not capable to understand about object permanence.He does not perceive that even when his train is hidden under blanket ,it will keep on existing even when it cannot be seen. Thus, he gets along with his father for nap because he think it is gone forever.