Behavior modification is a way of changing someone's behavior. Let's say your parents want you to clean your room more often. They might use behavior modification to try and make that happen.
Behavior modification works by giving you consequences for your actions. If you clean your room, you might get a reward, like a treat or extra playtime. But if you don't clean your room, you might get a punishment, like no TV or no dessert.
The idea is that if you keep getting rewards for good behavior and punishments for bad behavior, you'll start to learn that it's better to do the things that get you rewards. Over time, the hope is that you'll start cleaning your room more often because you know you'll get a prize for doing it.
Behavior modification is often used by parents, teachers, and therapists to help people change their actions. The important thing to remember is that the rewards and punishments need to be consistent and fair. That way, you'll know what to expect and what's expected of you.