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Behaviors that Puzzle: Repetitive Motions and Obsessive Interests in Autism

Marina Sarris
Interactive Autism Network at Kennedy Krieger Institute
Date Published: 
October 15, 2018

Some of a child's first 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.

Doctors call these repetitive and restricted behaviors and interests (or RRBs, for short), and they are a core symptom of autism. Researchers say RRBs are "almost always present" in young children with autism – as early as 12 months of age – and they persist over time as the child grows.1,2

Guidelines for diagnosing autism place a greater emphasis on these behaviors than they did in the past. Since 2013, when American psychiatrists published a new diagnostic manual, doctors have been looking for at least two such behaviors when diagnosing a patient with autism spectrum disorder (ASD).3 Previously, someone could receive a diagnosis on the spectrum with fewer such behaviors.


photo of boy holding a spinning toyDespite their importance in autism, repetitive behaviors are not unique to the condition. They can be found in toddlers who are developing typically or who have a disorder other than autism. But researchers say these behaviors are more common and severe in children on the spectrum.1 If a child has many types of these behaviors, he is more likely to have autism than another disorder.4

"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 at Kennedy Krieger Institute in Maryland. Dr. Wodka is Kennedy Krieger's principal investigator for SPARK, a U.S. study that seeks to involve more than 50,000 families of people with autism in research.

The repetitive behavior also must interfere significantly with a person's daily functioning, according to the psychiatric manual.3

Common examples include movements such as flapping one's arms, rocking from side to side, spinning in circles, or repeating nonsense phrases or sounds. The child also may move objects in ritualistic ways, such as flicking a light switch on and off, or spinning the wheels of a toy car, according to the U.S. Centers for Disease Control and Prevention.5 Clinicians call these stereotyped, or sometimes self-stimulatory, behaviors, while parents may simply call them "stimming."


pixabay photo of a child having a meltdownAnother type of RRB is a child's insistence that objects or his daily routines be exactly the same, day after day.3,5 He may become extremely upset if he cannot line up his toys in a certain way, if a picture on the box of his breakfast cereal changes, or if his bus takes a new route to school, for example.

In 1943, American psychiatrist Leo Kanner first described this symptom in 11 children with a condition he named autism. "The child's behavior is governed by an anxiously obsessive desire for the maintenance of sameness that nobody but the child himself may disrupt on rare occasions. Changes of routine, of furniture arrangement, of a pattern, of the order in which everyday acts are carried out, can drive him to despair," Dr. Kanner reported, in the first published description of autism.6 Today we may call that "despair" a meltdown or tantrum.

An intense fixation on an object (such as a vacuum cleaner motor) or a topic (dinosaurs) also may be a repetitive behavior. The child may be described as being obsessed with train schedules, a video game, or Thomas the Tank Engine, far beyond the level of other children.

Another common feature of autism – having unusual responses to noise, light, touch, smell or movement – may be considered a repetitive behavior, according to the manual for diagnosing autism. Examples include being insensitive to pain or temperature, extreme sensitivity to sounds or textures, the excessive smelling or touching of objects, and staring at lights or whirling fans.3


These are behaviors that really disrupt family routines.

Repetitive behaviors may interfere with a child's learning7 and cause stress for his family.8-10 That may be especially true if the child could hurt himself performing a compulsive behavior, or while having a tantrum when his routine changes slightly.

Parents often say 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.9,11 Some families may go to extremes to avoid any change in routine that could trigger a meltdown.

"These are behaviors that really disrupt family routines," said Brian A. Boyd Ph.D., director of the Juniper Gardens Children's Project at the University of Kansas, who has researched these behaviors in autism.


iStock photo illustration of toy ducks in a row with one out of orderAn important aspect of treating a behavior is understanding its purpose, Dr. Wodka explained. "Behaviors that are pleasing or reinforcing may require a different treatment approach than behaviors that serve to reduce discomfort or 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 at school, or a way to express her excitement?

Several interventions based on Applied Behavior Analysis – a form of behavior modification – have been used reduce repetitive behaviors, especially those that could result in injury, and to prevent meltdowns.

For example, children who have tantrums when they have to move to a new activity at school, or experience a change in routine, can be prepared for the change with a picture schedule and spoken reminders, according to a research article reviewing such strategies.11

Children also might be rewarded for gradually tolerating more changes. For example, a boy who lines up his cars in a specific order could be rewarded for tolerating a small change in the order, and then, gradually, rewarded for bigger changes.11

If a repetitive behavior is interfering with learning, a child might be provided with an assortment of other activities from which to choose. He also might be rewarded for other behavior – such as playing appropriately with toys – without having the troublesome behavior.11 Some research has even shown that children have fewer repetitive behaviors after exercising.12

But not all repetitive behaviors may need to be treated, especially if they do not interfere with a person's daily life.


Special interests may, in fact, be a special case. Of all the types of RRBs, these may be unique to ASD.4 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 their special interest, for example, Thomas the Tank Engine, than when another toy is involved.11


pixabay photo of cattle, a special interest in some people with autismWhat happens to these behaviors in adulthood? According to the psychiatric diagnosis manual, "Many adults with autism spectrum disorder without intellectual or language disabilities learn to suppress repetitive behavior in public. Special interests may be a source of pleasure and motivation and provide avenues for education and employment later in life."3

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

In a study of 687 adults with autism in the Netherlands, almost two-thirds reported having at least one special interest, such as computers, music, nature, and autism itself. Their average age was 42. Overall, they said, their interest had a positive effect on their lives. However, those who spent the most time per week on their special interest reported lower feelings of wellbeing.13

In an Interactive Autism Network (IAN) questionnaire of 250 independent 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. However, 45 percent of them said their interest sometimes interfered with their success at work or school, or in relationships. Almost a fourth said their interest had landed them in trouble, such as addictive behavior or legal problems.14

Some research points to gender differences in special interests. Girls with autism may have fewer special interests, or different ones, than boys on the spectrum, according to several studies.15-17 That also may be true for adults with ASD. In the study of Dutch adults, men were more likely to report a special interest than women. Popular interests among men included computers, gaming, and music, while women tended to favor nature and animals, gardening, art, and culture.13


Dr. Boyd, the researcher at Juniper Gardens, 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 ways of thinking and acting on the world. Right now, there isn't a drug that helps you be more flexible."

He advocates more research into repetitive behaviors, as well as early intervention to help children with autism become more flexible. "Early intervention may help children learn early on to tolerate change and cope better when uncertainty arises," 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 and severe."

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Additional Resources: 
  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 : Official Journal of the International Society for Autism Research, 3(4), 162-173. doi:10.1002/aur.142 [doi] Abstract.
  2. Wolff, J. J., Botteron, K. N., Dager, S. R., Elison, J. T., Estes, A. M., Gu, H., . . . IBIS Network. (2014). Longitudinal patterns of repetitive behavior in toddlers with autism. Journal of Child Psychology and Psychiatry, and Allied Disciplines, 55(8), 945-953. doi:10.1111/jcpp.12207 [doi]
  3. American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Arlington, VA: American Psychiatric Association.
  4. Lam, K. S., 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, and Allied Disciplines, 49(11), 1193-1200. doi:10.1111/j.1469-7610.2008.01944.x [doi] Abstract
  5. Centers for Disease Control and Prevention. (2015). Autism spectrum disorder (ASD): Signs and symptoms. Retrieved from
  6. Kanner, L. (1943). Autistic disturbances of affective contact. Nervous Child, 2, 217-250.
  7. Pierce, K., & Courchesne, E. (2001). Evidence for a cerebellar role in reduced exploration and stereotyped behavior in autism. Biological Psychiatry, 49(8), 655-664. doi:S0006-3223(00)01008-8 [pii]
  8. Gabriels, R. L., Cuccaro, M. L., Hill, D. E., Ivers, B. J., & Goldson, E. (2005). Repetitive behaviors in autism: Relationships with associated clinical features. Research in Developmental Disabilities, 26(2), 169-181. doi:S0891-4222(04)00089-7 [pii]
  9. Harrop, C., McBee, M., & Boyd, B. A. (2016). How are child restricted and repetitive behaviors associated with caregiver stress over time? A parallel process multilevel growth model. Journal of Autism and Developmental Disorders, 46(5), 1773-1783. doi:10.1007/s10803-016-2707-7 [doi]
  10. Bishop, S. L., Richler, J., Cain, A. C., & Lord, C. (2007). Predictors of perceived negative impact in mothers of children with autism spectrum disorder. American Journal of Mental Retardation : AJMR, 112(6), 450-461. doi:0895-8017-112-6-450 [pii]
  11. 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(6), 1236-1248. doi:10.1007/s10803-011-1284-z [doi] Abstract.
  12. 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.
  13. Grove, R., Hoekstra, R. A., Wierda, M., & Begeer, S. (2018). Special interests and subjective wellbeing in autistic adults. Autism Research : Official Journal of the International Society for Autism Research, 11(5), 766-775. doi:10.1002/aur.1931 [doi]
  14. Interactive Autism Network. (2014). IAN stats: Adult with ASD questionnaire (self-report) - 2.0.1. Retrieved from
  15. Hiller, R. M., Young, R. L., & Weber, N. (2014). Sex differences in autism spectrum disorder based on DSM-5 criteria: Evidence from clinician and teacher reporting. Journal of Abnormal Child Psychology, 42(8), 1381-1393. doi:10.1007/s10802-014-9881-x [doi]
  16. Hiller, R. M., Young, R. L., & Weber, N. (2016). Sex differences in pre-diagnosis concerns for children later diagnosed with autism spectrum disorder. Autism : The International Journal of Research and Practice, 20(1), 75-84. doi:10.1177/1362361314568899 [doi]
  17. Harrop, C., Jones, D., Zheng, S., Nowell, S., Boyd, B. A., & Sasson, N. (2018). Circumscribed interests and attention in autism: The role of biological sex. Journal of Autism and Developmental Disorders, 48(10), 3449-3459. doi:10.1007/s10803-018-3612-z [doi]