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A Brief Examination Of The Nature of Interests and Seeming-Obsessions in Autism Through The Lens Of The Hyper-Systemizing Theory

People who have autism are known to develop very intense interests for things in the world around them. These may revolve around an activity, but they can form around any manner of thing, really.

Whereas non-autistics have hobbies, autistics have “special interests.” I don’t know the specific reason for this change in nomenclature, but perhaps it is due to the typically intense nature of the interest, which can verge on obsession. All things considered, perhaps this makes sense. These special interests don’t always count as things that serve as hobbies; very often, it  may be something that seems completely random and non-sensical to anyone but the autistic (I assure you, however, that it means very much to them, even if you don’t understand the reasoning for it). This, however, is not a bad thing.

In many cases, the autistic individual has an encyclopedic knowledge level on their interest. While weather has always been a passion of mine (a topic, perhaps, for a later article), outside of that, probably the greatest interest in my life has been the Harry Potter books and movies. I’ve read the books several dozen times (even owning multiple copies over the years, as I read my originals so many times that they literally fell apart) and watched the movies several hundred times over the years. I frequently marathon through the movies (they never get old) and can quote nearly every scene of each. I’m even able to decently monologue certain characters. I know both the books and movies well enough that I can differentiate between the sometimes subtle book-to-screen changes in the movies, and fill in movie-related plot holes. Likewise, I have just as high an interest in and recall ability for the TV show Person of Interest. In addition to knowing the exceptionally-nuanced plot backwards-and-forwards and being completely familiar with every major character – from lines and quotes all the down to being able to mimic one character’s stiff-legged walk and another’s hand-to-hand combat mannerisms –  I have nearly total recall for every episode that has thus far aired (90, as of the end of season 4), and can recall an entire episode within a few minutes (though, more often, within seconds) of it beginning. If you want to avoid spoilers, I’m not the person you should talk to. But, if you want an in-depth analysis, or have missed an episode, I’m your guy… 😉

And I won’t even start on my extensive interest in Star Wars…. but I will say that I am a total fan who enjoys all the movies (yes, even the prequels… I had more issues with The Force Awakens [initially, at least – I’ve since mostly changed my mind] than I ever have with the last three Lucas-made movies) and the now-invalidated expanded universe.

Cognitive neuroscientist and psychologist Simon Baron-Cohen believes that autism predisposes one to have such intense interests, through what he calls “systemizing.”

The Hyper-Systemizing Theory is an evolution of Baron-Cohen’s Empathizing-Systemizing Theory, wherein “systemizing” is seen as the desire and ability to construct and identify “systems,” which can be anything that takes an input and produces a correlated output. The goal of systemizing is to determine if rules and/or patterns exist in something.

As Baron-Cohen once put it (2006):

“The hyper‐systemising theory of ASC [autism spectrum conditions] posits that human brains have a systemising mechanism (SM), and this is set at different levels in different individuals. In people with ASC, the SM is set too high. The SM is like a volume control. Evidence suggests that within the general population, there are eight degrees of systemising:

  • Level 1: Such individuals have little or no drive to systemise, and consequently they can cope with rapid, unlawful change. Their SM is set so low that that they hardly notice if the input is structured or not. While this would not interfere with their ability to socialise, it would lead to a lack of precision over detail when dealing with structured information. We can think of this as hypo‐systemising. Such a person would be able to cope with agentive change easily, but may be challenged when dealing with highly lawful non‐agentive systems.
  • Levels 2 and 3: Most people have some interest in lawful non‐agentive systems, and there are sex differences in this. More females in the general population have the SM set at Level 2, and more males have it set at Level 3. For example, on tests of map reading or mental rotation or mechanics, or on the systemising quotient, males perform higher than females.
  • Level 4: Level 4 corresponds to individuals who systemise at a higher level than average. There is some evidence that above‐average systemisers have more autistic traits. Thus, scientists (who by definition have the SM set above average) score higher than non‐scientists on the autism spectrum quotient (AQ). Mathematicians score highest of all scientists on the AQ. Parents of children with ASC also have their SM set higher than average and have been described as having the “broader phenotype” of autism. At Level 4 one would expect a person to be talented at understanding systems with moderate variance or lawfulness.
  • Level 5: People with AS [Asperger’s Syndrome] have their SM set at Level 5: the person can easily systemise lawful systems such as calendars or train timetables. Experimental evidence for hyper‐systemising in AS includes the following: (i) people with AS score higher than average on the systemising quotient (SQ); (ii) people with AS perform at a normal or high level on tests of intuitive physics or geometric analysis; (iii) people with AS can achieve extremely high levels in domains such as mathematics, physics, or computer science; and (iv) people with AS have an “exact mind” when it comes to art and show superior attention to detail.
  • Levels 6–8: In people with high functioning autism (HFA), the SM is set at Level 6, in those with medium functioning autism (MFA) it is at Level 7, and in low functioning autism (LFA) it is at the maximum setting (Level 8). Thus, people with HFA try to socialise or empathise by “hacking” (that is, systemising), and on the picture sequencing task, they perform above average on sequences that contain temporal or physical‐causal information. People with MFA perform above average on the false photograph task. In LFA, their obsessions cluster in the domain of systems, such as watching electric fans go round; and given a set of coloured counters, they show extreme “pattern imposition”. Box 1 lists 16 behaviours that would be expected if an individual had their SM turned up to the maximum setting of Level 8.”

Box 1: Systemising mechanism at Level 8: classic, low‐functioning autism

Key behaviours that follow from extreme systemising include:

  • Highly repetitive behaviour (e.g. producing a sequence of actions, sounds, or set phrases, or bouncing on a trampoline)
  • Self‐stimulation (e.g. a sequence of repetitive body‐rocking, finger‐flapping in a highly stereotyped manner, spinning oneself round and round)
  • Repetitive events (e.g. spinning objects round and round, watching the cycles of the washing machine; spinning the wheels of a toy car)
  • Preoccupation with fixed patterns or structure (e.g. lining things up in a strict sequence, electrical light switches being in either an ON or OFF position throughout the house)
  • Prolonged fascination with systemisable change (e.g. sand falling through one’s fingers, light reflecting off a glass surface, playing the same video over and over again)
  • Tantrums at change: as a means to return to predictable, systemisable input
  • Need for sameness: to impose lack of change onto their world, to turn their world into a totally predictable environment, to make it systemisable
  • Social withdrawal: since the social world is largely unsystemisable
  • Narrow interests: in systems (e.g. types of planes)
  • Mind blindness: since the social world is largely unsystemisable
  • Attention to detail: the SM records each data point in case it is a relevant variable in a system
  • Reduced generalisation: hyper‐systemising means a reluctance to formulate a law until there has been sufficient data collection. This could also reduce IQ and breadth of knowledge
  • Language delay: since other people’s spoken language varies every time it is heard, so it is hard to systemise
  • Islets of ability: channelling attention into the minute detail of one lawful system (e.g. the script of a video, or prime numbers)

Systemizing explains the nature of autistic special interests and other aspects of autism quite well; it makes sense of repetitive behaviors, and details ways in which they may sometimes manifest as special interests. As autism makes one feel less in control of their lives, systemizing enables control, and certainty. This is part of why autistics typically dislike change, and why they tend to be ritualistic, in establishing routines. 

Movies, books, and TV shows never change, and are therefore totally predictable (systemizable). This makes them strong candidates to be internalized, as in my experience above, when viewed repetitively. This is especially true when one feels that they relate to characters in some way, or when the plot somehow engages them on a personal level. But this is just one example; there are many others besides, including math, facts and statistics, and weather. Systemizing also manifests through self-stimulating behaviors, as a way to reduce tension or stressors that are affecting the individual.

Systemizing is not a bad thing by any means. It should be considered that strong skills in systemizing are a positive of autism in many cases, and even as an indicator of talent (especially when combined with certain hyper-sensory factors of autism, as outlined in that journal article). Rather than being looked down upon or discouraged, as long as they are appropriate and in moderation, special interests should be encouraged, because they can be quite beneficial to the individual pursuing them.

This article was not meant to be an exhaustive analysis, nor very technical; rather, it is a quick read mixing personal experience with a bit of theory. Hopefully it has been informative and interesting to you. For more information on the theory behind the concept of systemizing, I encourage you to check out For another (less theoretical) look at special interests in autism, I encourage you to read this excellent article.

Published inAutismDisordersEducation


  1. McGranma McGranma

    You are getting better and better at explaining things so people can really understand the extent of autism and all its different facets. Keep up the great work on educating us.

  2. Grandma Grandma

    Matt, sorry I didn’t see this sooner. I just finished reading what you wrote . It is a fantastic article and very interesting. You make articles like this to understand easier. You are a very good writer and the way you put it all together is great. I am so very proud of the young man you have become. Love ya

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