A concept developed by Raymond Cattell, Source Traits are the building blocks or sources of human personality. Cattell believed there are 16 of these source traits.
For example, a person may be reserved or outgoing, serious or happy-go-lucky, and submissive or dominant. All these traits form part of an individual's personality. When you put the source traits together, the make up the Surface Traits, which are the traits we see and think of as personality.