Genetic factors account for much of the variation in personality traits across the lifespan. Shared upbringing plays a smaller role in adult personality than many clinical models assume.

Most people believe that personality is generally very stable—and in many ways, they’re right. If you are an extravert, for example, it’s not quite possible for you to turn into an introvert overnight ...

Some people believe personality is fixed, but more recent research suggests that personality may develop over time and that people’s personality traits can change. Personality types group people into ...