Baby Tuan loves to stand at the window and watch cars drive past. When he wants to play with his toy cars, Tuan will make engine noises until his mother gets them out of the toy box. Piaget would say that Tuan has acquired the cognitive concept of .

symbols

Explanation:

The cognitive concept of symbols suggests that a person can resolve the problem using the interpretation capacity. The symbols helps in creation of space that allows for the interpretation of the knowledge and relating them with the practical application.

Here, in the given situation the Baby Tuan has acquired the cognitive concept of symbols. This is because of the fact that Baby Tuan is learning while observing the cars that drive past from the window and trying to make the sound of engine while playing with own toys. Thus Tuan is applying on own toys what he observed.