People with Autism have intense interest from a fairly young age. This can sometimes change over time or be lifelong. For example, music, trains, numbers, shape, particular cartoon characters, dinosaurs e.t.c.
They might also be attached to objects such as toys or unusual objects like stones, leaves, shoes e.t.c. This is believed to make them feel relax or happy. The intensity and duration of interest that makes it out as obsession.
Repetitive behaviour
This may include arm or hand flapping, rocking, jumping, spinning, twirling or complex body movements. Sometimes, there is the repetitive use of objects, e.g twirling a piece of string. This behaviour is known as swimming or self -stimulating behaviour.
Repetitive behaviour varies with each person but, the reason for this behaviour may br the same.
. To reduce sensory input, e.g focusing on a particular sound to block out distressing environment.
. To gain sensory input, e.g rocking may be to stimulate balance.
. To deal with stress.
. To provide satisfaction.
Routine
The autistic person can find the world unpredictable hence, the need for daily routine. This helps them know what is happening daily. They may want to travel on the same way to and from school or eat same food on a daily basis.
Changes like moving homes, changing school, holidays can be distressing for autistic person and can cause anxiety.
They might have rigid preference about food, wanting same food in a certain taste colour and texture. They might prefer certain clothing or using everyday objects. Routine can become almost ritualistic in nature, following it precisely and attending to all details.