Ming from Agents of Speech explains why autistic children have meltdowns: they struggle with uncertainty and changes to their environment. A student couldn't handle a mall that had been rearranged during lockdowns. Gradual exposure helps them build tolerance.
The main reason why ASD children or people get stressed out and have tantrums and meltdown is because intolerance to uncertainty. So anyone will get anxious when things happen, when you're doing something you've never done before. But it's maybe nearly everything in their life. If ASD child hasn't been to a mall before, there's loads of lights, sounds, crowds, people around, and what happens is that it becomes something new, so they cannot deal with it. And when this happens, they get really anxious. They don't know what to do. So the tolerance to uncertainty is a lot lower. So anything outside of their root routine, they will not like. For instance, a student of mine, when she goes to a mall during the pandemic, it looked very dark. It didn't have all the lights on. There were less people. All of the stores were closed down because of the quarantine, the lockdown. What happened was that she couldn't take it, didn't like it that the mall had changed so much she couldn't do it. That is why most of the time we have to slowly and in a controlled manner to help them deal with anxiety.
