2. Repetitive Behavior Patterns
A child with autism has a tendency to mimic certain behaviors. One of the most common sign of autism in a child is when he or she jumps repeatedly. Other behaviors include repeatedly making sounds or stacking things on top of each other and doing it over and over again.
A lot of times, the autistic child will perform hand-wave motions repeatedly or some other actions that they find pleasurable to do. Since they are immersed in these actions and behavior patterns, these kids find it difficult to handle any changes in their surroundings and their daily routine.