Positive reinforcement training for discouraging biting or aggression in dogs involves rewarding desired behaviors with treats, praise, or play, thus reinforcing the behavior you want to see. Start by rewarding calm and non-aggressive interactions with people and other animals. Use treats to distract and redirect potential aggressive behavior towards more acceptable actions. Consistently practice commands like 'sit' or 'stay' to manage your dog's impulses and maintain control in potentially provocative situations. Socialization exercises in controlled environments can also help reduce fear and anxiety, decreasing the likelihood of aggressive responses.