We all know that as we age we go through many monumental changes. Not only do we physically change, we also mentally change and this was exemplified by Piaget's Stages of Development. Out of all of the concepts that we have learned throughout Psychology, this concept will remain the most distinct because of its importance in our life. Piaget's stages outline the progression from simple thinking as we are very young, to gradually higher levels of thinking as we progress in age. Concepts such as object permanence, deferred imitation and thinking of the "here and now" progress and become applicable to every day life as we grow up. The reason why these concepts are going to stick with me rather than any other concepts we learned in psychology is because it applys to our full lifetime and characteristics as we age and through our gradual lifetime rather than a fixed point or certain period in our life.