Trait is a personality system in The Sims 4, similar to the trait system in The Sims 3. The personality system as a building block of Sims in The Sims 4 is a combination of traits from The Sims 3 and aspirations from The Sims 2. There are four kinds of traits in the base game: personality, bonus, death, and reward. Each kind has different ways to earn them.