Personality psychology
Personality' is a term that  describes traits  a person shows consistently at different times and in different situations. If we understand a person's personality we may be able to predict their behavior in many situations. Predictability makes it possible to explain and understand behavior. A person's personality can often suggest their internal thoughts, feelings, and behaviors. Intrapersonal functioning is a term used to describe the stable processes that underlie these thoughts, feelings, and behaviors. Carver, Charles S., and Michael F. Scheier.