Preoperational children cannot hold several aspects or dimensions of a situation simultaneously in mind. this limitation is called

Preoperational stage is one of the four cognitive stages in the Piaget's developmental sequence, together with the sensorimotor; 
concrete operational and formal operational stage. The limitation in which preoperational children cannot hold several aspects or dimensions of a situation simultaneously in mind is called operations. Operation is defined by Piaget as is the ability to accurately imagine the consequences of something happening .