When I think about addressing challenging behavior, I automatically start thinking of what I'm going to teach. After all, we can't expect a child to stop doing something that has worked for them without teaching them how to do something more effective in it's place. This is often referred to as a replacement behavior. Almost without exception, people engage in challenging behavior to either get something they want or get out of something they don't want to do. This applies to ALL people - not just children and not just people with disabilities.
When thinking about challenging behavior from the lens of getting or getting out of things, it becomes apparent that teaching kids to negate, or ask for "no" appropriately, is critically important. Teaching kids to ask for or say "no" appropriately teaches them to be their own advocates and helps avoid problem behavior that stems from escape and avoidance. As adults, we do this all the time with varying degrees of success. Recently, we had a door to door exterminator come to our front door. He made a convincing pitch, but to be perfectly honest, I was so far from interested (and a little annoyed that he interrupted dinnertime for my son). I had to tell him politely but firmly that no, we were not interested in his services. Even as an adult, I struggle with telling others "no" and "stop". Saying no effectively but kindly is a skill that most of us hone throughout our lives as we continue to develop our self advocacy skills. We owe it to our kids to teach them early how to say "no" or "stop" in a way that can be heard, understood, and respected without having to resort to challenging behavior.
When teaching your child to say "no" or "stop" appropriately, first identify what you expect him or her to say or do. We highly recommend keeping it simple, especially if their go to negation method is currently crying, yelling, or some other form of problem behavior. A simple side to side head shake, exchange of a "no" card, or saying "no" calmly with an appropriate voice volume are all great replacements for challenging behavior that communicates no. Once your child has a simple communication response, it might be appropriate to start adding in complexity, such as social niceties such as "No thank you" or "Stop please" and contingencies like "Can I do it later?"
Remember, teaching your child to say "no" or "stop" to things they want to escape or avoid is different than you telling them "no" to requests you can't say yes to. Both skill sets are so important to behavioral and communication development. We believe that the sooner we can teach our kids and young adults to be effective communicators, the better off they will be in building the skills needed for life. Be on the lookout for a new post soon on the importance of accepting "no" following a request.