In socionics, functions are the states of the psyche and actions a person takes in these states. They are the mutable shell of personality and one of the focuses of attention. A person's functional profile changes over time—some functions strengthen while others weaken throughout life. This can lead to significant transformations in character and lifestyle, especially noticeable during age crises or other life upheavals. At these points, we can redirect the development of the psyche. Therefore, the psyche does not have a single correct or predetermined scenario for change. Much is in the hands of the individual, who can develop in different ways.