Behavioralism is a way of understanding why people do things based on their behavior. Imagine you are trying to teach a puppy a new trick. When the puppy does the trick correctly, you give it a treat. When it doesn't do the trick, you don't give it a treat. This is called "positive reinforcement" - rewarding good behavior to encourage it to happen again.
Behavioralists think that people, like puppies, can have their behavior changed by how they are rewarded. If you get praised for doing something well, or you get a treat for doing it, you are more likely to do it again in the future. The opposite is true as well: if you get punished for doing something wrong, or you lose a privilege, you are less likely to do it again.
Behavioralism is all about studying behavior and figuring out what rewards and punishments can influence it. This approach often uses experiments and observation to see how people behave in different situations. By understanding how people's behavior can be shaped, behavioralists hope to create better ways to teach, train, and even prevent problems like addiction, crime, or mental illness.