People are unique primarily because of differences in personality and beliefs. Every person has a different way of perceiving the world around him and attaching meaning to different situations. The characteristics of an individual are formed in early childhood and continue to change throughout adolescence and adulthood.
Personality is a term used to describe the traits that make people different. It is a topic that has been studied extensively in the fields of psychology and psychiatry and remains to be one of the most fundamental ways in which experts determine the traits that make a person unique. According to Psychology Today, an individual's personality cannot be accurately understood because "there is no way to tell who we were to begin with or who we were meant to be." As a result, a person's uniqueness from another is determined through standardized tests and professional consultations with psychologists or psychiatrists, which are all limited because they do not accurately reflect what a person may be thinking or feeling during the test or consultation. In addition to personality, a person's beliefs, spirituality, thoughts, creativity, goals and genetics also determine how unique that person is from someone else. Intelligence and age also play an important role in shaping the unique characteristics of an individual over the course of a lifetime.