From the perspective of Piaget, Jake is entering the Formal Operational stage of development. This means he has progressed from an egocentric perspective, through the concrete operational stage in which he would have learned how to manipulate objects in his environment and understand the process of conservation (even though an object may change shape and form, it maintains some if its original characteristics). Now, Jake is entering a new stage in which he will progress from understanding his role in relation to objects around him and the power he might influence over them to understanding his role in relation to his peers. He will begin to learn that his peers hold differing opinions and values, and he will explore his own values in relation to his peers. He may also begin to develop the ability to reflect on his own thoughts (referred to as "metacognition") and to wonder about his thoughts in relation to the thoughts of others. He may begin to wonder about morality.
From the perspective of Erikson, Jake is entering the Identity vs. Role Confusion stage. In this stage, Jake is exploring his role in his family of origin and looking beyond that to understand his role in society as a whole. Who will he be? How will he act? Who will his friends be, and how will they behave in relation to him? Who will he love? If he is able to navigate this phase successfully, he will achieve fidelity, which is a sense of himself that holds true, and he will be able to accept that others have opinions that differ from his.
From the perspective of Kohlberg, Jake will be navigating moral dilemmas as he enters the stage of Morality of Autonomous Moral Principles. This means he will be weighing the complex issues of what is right or moral versus what is legal or mandated by law. He will also be considering the effects of decisions on individuals and society as a whole. This stage of development will likely continue for the rest of Jake's life.