How personality traits are given is determined by whether the Sim was born in game or created in CAS (Create-A-Sim). Making your Sims in CAS lets you pick a number of personality traits based on their age (see below). Sims born in game are given two traits not of your choice. From then on you have a choice. When a Sim ages well you pick the trait. Ages badly, the game randomly picks one. Could be good, could be bad.
Personality Traits by Age:
- Baby: 2
- Toddler: 2
- Child: 3
- Teen: 4
- Young Adult: 5
- Adult: 5
- Elder: 5
Personality traits will determine how Sims respond to others and their preference for how to use their "extra" time. A kleptomaniac can steal, while a technophobe avoids the TV. Lifetime wishes are based on personality traits as well.
