Brian grew into adulthood with the goal to have a family that didn't use violence to solve problems. some people said it was in his genes to naturally get angry, but brian learned to control it. he chooses to use his words to express his displeasure instead. which theory describes brian's choice to not use violence? determinism free will combination of both neither

The theory of free will describes Brian's choice to not use violence. 

Free will can be defined as the freedom individuals have to choose their own life outcomes, behavior and actions. The theory of free will is the opposite of the theory of determinism which claims that our life outcomes, behavior and actions are determined by external factors outside our control (genetics, our fate, God, astrology, etc.) In this instance when Brian decided not to use violence to solve family problems, he is exercising his free will.