Behaviors That Puzzle: Repetitive Motions and Obsessive Interests in Autism

Marina Sarris
Interactive Autism Network at Kennedy Krieger Institute

Date Last Revised: November 14, 2013

Date Published: December 18, 2012

Some of a child’s early symptoms of autism may be among the most puzzling to parents: hand-flapping, rocking, lining up toys, or finding the whirling blades of a fan more interesting than the world around him.

Psychologists call these repetitive and restricted behaviors (or RRBs), and they are a main feature of autism spectrum disorders (ASD). Research says they are “almost always present” in very young children with ASD and persist over time as the child grows.1

New guidelines for diagnosing autism place a greater emphasis on these behaviors. Doctors now look for at least two such behaviors when diagnosing a child with autism spectrum disorder, since the publication of a new edition of the psychiatrists’ diagnostic manual in 2013. Previously, a child could receive a diagnosis on the spectrum with fewer such behaviors.

What are Repetitive and Restricted Behaviors?

Repetitive behaviors can occur in toddlers who are developing typically or have a disorder other than autism, but according to research, these behaviors are more common and severe in young children with a spectrum disorder.1 If a child has many types of these behaviors, he is more likely to have autism than another disorder.2

“What is really defining about the behavior is that it is unusual, appears non-functional, and occurs over and over again,” said Ericka Wodka Ph.D., a pediatric neuropsychologist in the Center for Autism and Related Disorders and the Department of Neuropsychology at the Kennedy Krieger Institute.

Some common examples are body movements such as flicking fingers in front of one’s eyes, rocking back and forth, moving objects (opening and closing doors), or spinning in circles.3 More troubling repetitive behaviors are those that could injure the child, such as slapping himself over and over.

Another type of RRB is a child’s insistence that objects or his routines be exactly the same. For example, he may have a meltdown if his bus takes a detour to school or if he is prevented from lining up his cars a certain way.

An intense absorption with an object, a part of an object, or a special interest or topic also falls into this category of behavior. The child may be described as obsessed with train schedules, a video game, or Thomas the Tank Engine, far beyond the level of typical children.

Researchers have theorized that sensory problems – unusual responses to noise, light, touch, smell or movement – may trigger some RRBs in autism. Some people are sensitive to bright lights, loud noise, the texture of clothing or food, or other sensations. However, others barely respond to sensory input, such as heat, cold or physical discomfort. Some research suggests that one type of sensory problem – being over-responsive to sensations – is more often related to RRBs than other sensory issues are.4

Problems Caused by RRBS

Repetitive behaviors may get in the way of learning and cause stress for families. “Parents commonly report that repetitive behavior symptoms are among the most difficult aspects of the disorder they have to tackle on a daily basis,” according to a research article.4

Parents may feel stigmatized by their children’s flapping or other unusual motions. Some families may even go to extremes to avoid any change in routine that might trigger a meltdown in their children.5

“These are behaviors that really disrupt family routines,” said Brian A. Boyd Ph.D., assistant professor in the Division of Occupational Science at University of North Carolina at Chapel Hill.

What Can be Done About These Behaviors?

An important aspect of treating a behavior is understanding the purpose of it, Dr. Wodka explained. “Something that is pleasing is not going to be responsive to the same kind of intervention as something that is a response to anxiety,” she said.

A behavioral assessment can help determine the underlying function of a behavior, which may be different for each person with autism and for each type of behavior.

Does a girl flap her hands, for example, because she’s anxious or because she finds it enjoyable? Is it a way to avoid a task she dislikes or a way of communicating?

Interventions based on Applied Behavior Analysis – a form of behavior modification – may help reduce some RRBs.

For instance, to reduce flapping or hand-biting, an adult may remove a desired “positive consequence” (playing with a favorite toy) when the child engages in the behavior, according to a 2012 article by Dr. Boyd and two other researchers.  Or, the adult may reinforce and reward positive behaviors, such as paying attention, rather than the RRB. Some research has even shown that children have fewer repetitive behaviors after jogging. 6

One way to help a person who insists on sameness is to reward him for gradually tolerating more changes in his routine. A child who lines up his toys in a specific order could be rewarded for tolerating a small change in the order, and then, gradually, rewarded for bigger changes.4

Unfortunately, there are relatively few studies of effective treatments for behaviors such as insistence on sameness and intense special interests, which scientists call higher-order behaviors.

A Special Kind of Restricted, Repetitive Behavior

Special interests may, in fact, be a special case. Of all the types of RRBs, these may be unique to ASD. They also may not, in themselves, be something that people need to treat.

“They aren’t necessarily always seen as problematic behaviors,” Dr. Boyd said. “Sometimes they are seen as islands of ability for a child.”

Some researchers have found that a child’s special interest can help improve learning and appropriate behavior when it is used as a reward for accomplishing a less desirable task, or as part of a social activity. For example, some preschoolers with ASD have more social interactions with a peer when their play involves Thomas the Tank Engine (a special interest) than when another toy is involved.4

Special Interests in Adulthood

In an Interactive Autism Network (IAN) questionnaire of 250 adults with ASD, 84 percent reported having a special interest or topic. A majority of those said they enjoy activities or develop relationships based on their topic, or have a job or field of study related to it. Some, however, said their interest sometimes gets in the way of success at work, school and in relationships (45 percent), or has gotten them into trouble (23 percent). Common interests include animals, computers, music, science and science fiction.7

Famously, Temple Grandin Ph.D., who has autism, turned her special interest in animals into a notable career as an animal scientist and designer of livestock handling facilities.

Starting Early and Moving Forward

Dr. Boyd, the researcher at UNC, theorized that repetitive behaviors, from rocking to special interests, may differ widely, but they have one thing in common. “What connects this broad category of behavior is inflexibility. Maybe the reason the child spins the top all that time, or the reason someone talks about the same topic over and over, is that they are inflexible in their thinking. There isn’t a drug that helps you be more flexible.”

He advocates more research into behavioral interventions for repetitive behaviors, especially the less studied higher-order ones, along with early intervention.

“Early intervention may help children learn early on to be more flexible,” he said. “The concern is that if you don’t address some of those things early, they become more difficult as children age and the behaviors become more ingrained.”

Additional Resources: 

See Challenging Behaviors.


  1. Kim, S. H. & Lord, C. (2010) Restricted and repetitive behaviors in toddlers and preschoolers with autism spectrum disorders based on the Autism Diagnostic Observation Schedule (ADOS). Autism Research. 2010 Aug;3(4):162-73. Abstract.
  2. Lam, K. S. L, Bodfish, J. W. & Piven, J.  (2008) Evidence for three subtypes of repetitive behavior in autism that differ in familiality and association with other symptoms. Journal of Child Psychology and Psychiatry 49:11, 1193-1200. Abstract
  3. Centers for Disease Control and Prevention, Autism Facts,
  4. Boyd, B. A., McDonough, S. G. & Bodfish, J. W. (2012) Evidence-based behavioral interventions for repetitive behaviors in autism. Journal of Autism and Developmental Disorders 42:1236–1248. Abstract.
  5. Bishop, S. L., Richler, J., Cain, A. C., Lord, C. & Floyd, F. (2007). Predictors of Perceived Negative Impact in Mothers of Children With Autism Spectrum Disorder. American Journal on Mental Retardation: November 2007, Vol. 112, No. 6, 450-461. Abstract.
  6. Kern, L., Koegel, R.L. & Dunlap, G. (1984). The influence of vigorous versus mild exercise on autistic stereotyped behaviors. Journal of Autism and Developmental Disorders 14(1), 57-67. Abstract.
  7. IAN research.
These archived articles were originally published as part of the Interactive Autism Network (IAN) research project. 
The project is closed and no longer accepting participants.

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