Jean Piaget's Formal Operational Stage begins at the age of twelve (or close to) and extends well into adulthood. In this initial stages, the ability of abstract thought processes begins to develop. People in this stage begin using logical and deductive thinking.
Parents and teachers, in order to facilitate cognitive development within this stage, can use problem solving, hypothesis creation, scenario questions, and cause/effect problems.
For example, deductive reasoning requires people to may educated inferences and conclusions about categorical information. IN the classroom, a teacher could begin examining the "If A=B and B=C then, C=A" equations and problems. In some cases this is correct, and in other cases it is incorrect.
In literature, the study of imagery, allusions, metaphors, and similes can be used to facilitate cognitive development in the Formal Operational Stage.
Parents could ask questions about what happens next scenarios. A great way to do this is through "America's Funniest Home Videos." A parent could pause a video before the climax and ask the child to consider the environment and what is happening. The child would then make a hypothesis about what will happen next.