The HIPPEA Model of Autism

So! I have a new research rabbit hole that has captured my attention. It comes from cognitive science, which is not really my field, but it relates to autism and disability theory in some very interesting ways. My primary source for what follows is a 2014 paper by Van de Cruys et al., titled “Precise Minds in Uncertain Worlds: Predictive Coding in Autism,” which you can find in full at that link. I’ll include a full citation for it at the end of this post as well.

Let’s start with the words “predictive coding” in that title. The basic gist of predictive coding models (if I understand correctly) is that our brains make predictions all the time about what to expect from our environment (including our internal environment). Those predictions happen on various levels in a hierarchical way, with more complex predictions happening at a higher level than more basic processes, such as sensory input. We base these predictions on mental models of our environment, and we can update those models when our predictions fail.

Of course, the sensory world is not always predictable; in fact, it mostly isn’t. Nothing is ever exactly the same from situation to situation, plus our biological sensory systems aren’t perfectly accurate or consistent. Differences between our predictions and reality are called prediction errors, and as I mentioned above, those errors can be used to update our internal models—in other words, we can learn from them. But to be efficient in that learning, we need to be able to determine which of those errors are due to important changes in our environment that we should learn from (signal) versus random fluctuations in either our environment or our sensory systems (noise).

This involves having an idea of how much natural variability there is in the situation or environment; if something is different, we want to know if that’s an expected difference (which can therefore be ignored) or an unexpected one (which we should learn from). In the paper mentioned above, this is called “meta-learning”—learning what can be learned. Ideally, prediction errors are weighted such that differences that seem important (signals) are used to adjust the model while those that seem random are ignored. That weighting is based on what is called the “precision” of our prediction errors, which is an estimate of how much variability we expect in the system. If precision is high, it means we want to pay attention to more of these prediction errors, because we expect them to be meaningful; if precision is low, it means we expect most of that variability to be random noise that can be ignored.

With me so far? Because this is where the HIPPEA model of autism comes in. HIPPEA stands for “High, Inflexible Precision of Prediction Errors in Autism,” and it basically suggests that the precision of our sensory prediction errors is constantly on “high.” This means that we treat every incoming difference between our predictions and the environment as being important and meaningful, no matter how small and/or random it is. So we are constantly updating our models and learning from all of our sensory input, instead of treating some of it as random and ignoring it.

If that sounds exhausting, that’s because it is. Constantly feeling like we’re adjusting to new information results in chronic uncertainty, which leads to anxiety. And the more complex the sensory environment is, the more energy it takes and the more uncertainty we’re likely to encounter—and one very complex environment is the social environment. As Van de Cruys et al., put it, “we wonder whether social may just be a synonym of complex here” (p. 665, italics in original).

As laid out in their paper, this model predicts a number of common features of autism, including executive functioning issues, sensory perception differences (including sensory overload due to a constant influx of prediction errors), face recognition difficulties, and atypical social communication. One aspect that really caught my attention, though, had to do with stimming. As the authors pointed out, in addition to making predictions about our environment, we also make predictions about the outcomes of our actions; for example, I make a prediction that if I press down on the space bar on my keyboard, it will advance the cursor on my screen. I expect a certain tactile feedback from the keyboard, and visual feedback from my screen, and unless my space bar is stuck (or my hands aren’t where I thought they were), I get both.

In this model the purpose of stimming, then, is to create feedback that is predictable—predictable because it is something we ourselves initiated. I flap my hands and feel them flap; I rub something soft and feel the softness; I make a sound and immediately hear it. If I am in an environment where everything else feels unpredictable—meaning that I am adjusting to a large number of prediction errors—generating sensory input that is predictable helps to mitigate that. This is the case even when the form of stimming might otherwise seem to make sensory overload worse (like blasting loud music when you’re on the edge of a meltdown; yes, it’s loud, but I made it loud).

The HIPPEA model is still relatively new, and more research is needed to test its applicability, but I find it very intriguing, and a lot of it really makes sense to me. I initially came across it in another very interesting paper, Legault, Bourdon, and Poirier’s “Neurocognitive Variety in Neurotypical Environments: The Source of ‘Deficit’ in Autism” (2019). This paper used the HIPPEA model to argue that the so-called cognitive “deficits” in autism are actually caused by a mismatch between the kind of environments favored by autistics and the predominance of environments created by and for neurotypicals.

As Legault et al. explain it, HIPPEA suggests that autistic people end up with “overfitted” mental models: because we are constantly refining them based on every new piece of information, they become very detailed and very specific, but less generalizable to other situations. Neurotypicals, on the other hand, tend to have “underfitted” models, with less detail but more general applicability. Because they’re not including everything, they can tolerate (and even enjoy) much noisier, more unpredictable situations. They can also find new social situations more familiar, because they can generalize from their models, while we’re analyzing all of the differences.

Meanwhile, being in their environments leaves us exhausted trying to process all of the noise (both literal noise and figurative noise-as-opposed-to-signal noise) that they’re ignoring. But that’s where we typically are—in environments that favor the neurotypical form of prediction processing (not to mention the neurotypical definition of what is considered worth paying attention to). And as Legault et al. pointed out, framing autism as a set of “deficits” in autistic people ignores this imbalance in who gets to define the dominant social environment(s) in which we find ourselves.

So that is what I have been reading this weekend, and again, it really makes a lot of sense to me. But it’s also still a fairly new model, and I haven’t explored every aspect of it in depth (and again, cognitive science isn’t my field). Any misunderstandings or misstatements in how I’ve presented it are unintentional, and if you think I’ve made any, please let me know. And please let me know how you think this model relates (or not) to your own experience!


Legault, M., Bourdon, J. N., & Poirier, P. (2019). Neurocognitive variety in neurotypical environments: The source of “deficit” in autism. Journal of Behavioral and Brain Science, 9(6), 246-272.

Van de Cruys, S., Evers, K., Van der Hallen, R., Van Eylen, L., Boets, B., de-Wit, L., & Wagemans, J. (2014). Precise minds in uncertain worlds: Predictive coding in autism. Psychological Review, 121(4), 649-675.

Finding Your People

One of the common themes in a great deal of autobiographical writing by autistic people is a pervasive sense of not fitting in, even among one’s own family. That’s one of the reasons that learning that one is autistic later in life can come as a profound relief; after a lifetime of feeling different, there is finally a name for that difference—or part of it, anyway. (Being autistic isn’t the only way a lot of us are different from others, but I think it’s often related.) Having that understanding often replaces a feeling of simply being bad or wrong for not fitting in or doing things “right.”

But having a name for it also does something else that has been equally profound for me: it provides a way of looking for others. Learning that you’re part of a neurominority gives you the language to seek out others in that same minority, with whom one might find common ground. Of course, like any minority (or majority, for that matter), autistic people are not monolithic; common ground isn’t necessarily automatic. But I have found—and have heard it echoed by many others—that it often takes less effort to connect with the thought processes and interaction style of other autistic people than with the world at large.

I have noticed that descriptions of autism often include depictions of non-autistics as “naturally” understanding social interaction and social cues in a way that we do not. But a great deal of research in sociology and social psychology has centered on a) common breakdowns in such communication, b) understanding how people learn these things through the process of socialization, and c) how they differ across cultures. They’re not innate, and they’re not infallible—not for anyone.

Now, maybe that begs the question of why autistic people don’t seem to absorb the same lessons about social expectations as others; there seems to be something innate that makes our social styles different. (I suspect a combination of monotropism and sensory differences, which may themselves be related.) But the impact of that difference can vary by culture, too: for example, cultures vary in how, and how much, eye contact is used. Being in a subculture focused on a particular interest feels different than being in a group of people making small talk. The social environment you’re in shapes social expectations, and makes it more or less likely for you to be able to meet them.

So finding other people who have a similar social style can feel like coming home to one’s native culture after trying to make do in one that is different and much less comfortable. A lot of us get pretty good at the latter, but that doesn’t mean it’s easy. And when it seems easy to everyone around you, it again starts to feel like you’re bad or wrong. Finding other neurodivergent people who are similar to you (which, again, won’t necessarily be all of them, and I also don’t mean to say connection isn’t possible across neurotypes) can go a long way toward alleviating those feelings by reflecting back a different way of being and socializing that feels more like home.

This is one more reason I embrace the label of “autistic” as a social identity, as I mentioned in a recent post. Doing so has allowed me to find community. It’s not my only community, but it is extremely precious to me. It is my hope that identifying as autistic will also allow others to connect with me, so we can build that kind of community for more of us.

Difference, Disability, and Disorder

Part of being autistic means that I process things differently than most people. Sensory input, social cues, emotions, physical sensations, information from spoken or written words—all of these come in (or arise within me) with varying degrees of intensity, and sometimes get tangled up with one another. Sensory input can distract from social cues, for example, and information in spoken form may be missed if I am trying too hard to attend to social expectations. And both social and sensory input can easily become overwhelming and/or draining, especially if I encounter high levels of both at the same time.

The way I present my own thoughts and reactions to things is different, too; I gesture extravagantly when I talk, but my facial expressions are often minimal, and may not reflect what’s going on inside. I don’t have much vocal inflection unless I really pay attention to it, and I prefer to converse for information rather than social purposes. Plus I often see patterns and connect dots many people don’t, and this sometimes makes it hard to follow my line of thinking unless I explicitly outline each step (which I often neglect to do because they seem so obvious to me).

These things make me different, and they can also sometimes be disabling. Or, to be more precise, they can lead to my being disabled by certain situations—the social and sensory overload at my reunion dinner earlier this month is a good example. (And I didn’t even mention the huge crying meltdown I had when I finally got back to my hotel room and tried to get to sleep, as well as the exhaustion I felt for the whole week afterward.) I have also been at a disadvantage in social interactions such as job interviews, where “people skills” and nonverbal communication are evaluated at least as much as experience. And, of course, I have experienced my share of social exclusion, especially when I was younger.

So in some contexts, I have felt disabled by my differences. But does that make them “disordered”?

Autism is, of course, defined in the Diagnostic and Statistical Manual of Mental Disorders. Its entry also has “disorder” right in the name: “Autism Spectrum Disorder.” And like most other entries in the manual, its diagnosis assumes impairment of “normal” functioning. But this glosses over some important considerations about what constitutes “normal.” Especially when it comes to “disorders” of social communication, the social context is at least as important as any individual “impairment.”

Research into autistic social communication has found that misunderstandings between autistic people and non-autistic people are a two-way street, something that sociologist Damian Milton has termed the “double empathy problem.” Meanwhile, some other new research has shown that social interactions between autistic people are as effective as those between non-autistic people in terms of communicating information and generating rapport. Where communication breaks down is between autistic and non-autistic people (again validating Milton’s concept of the “double empathy problem”).

These findings reflect my own experiences, although of course there are autistic people I don’t connect well with, and non-autistic people I am very close to. But to say that my social and sensory differences constitute a “disorder” in contrast with “normal” functioning is…well, normative. Would I really be better off if I could tolerate, or even enjoy, an experience like my reunion dinner, but lost the sensory sensitivity that allows me to notice so many subtle aspects of my environment? Or if I cared more about social standing and interaction than getting lost in hyper-focused research into a favorite topic? Being like the majority has its advantages, but so does being me.

So yes, I am different. I am sometimes disabled by the combination of my differences and inaccessible environments or rigid social expectations. But I reject the label of “disorder” even as I embrace the label of “autistic.” Learning that I’m autistic has been immensely helpful. Knowing this earlier might have helped me avoid the massive burnout I experienced in my early thirties, due to not understanding my own social and sensory needs. Because in the right environment, or with the right supports, I don’t feel impaired, and I have no problems socializing. (I had a lovely dinner with friends two nights ago, for example.)

That burnout hit me hard, and led to reduced employment and financial difficulties. It also forced me to make a lot of changes in my life in order to cope with stress. Many of those changes were positive, and all of them put me on a good path in the long run, but it was a tough transition (and it would still be years until I got my diagnosis). And certainly there are autistic people with challenges different from mine, and/or with additional disabilities, who find the world a lot more disabling. But whenever I think about ways to make the world better for autistic people across the spectrum, they don’t involve changing us. Instead, they involve making things more accessible to people with varying sensory and social needs, people with different communication styles and methods, and people who experience the world differently.

Removing my differences would also make me fundamentally different. That might make me more like others, and closer to the norm, but who is to say that would make me better? And who is to say that the world would be better for it, too?

Various Goings-On

It’s been a busy summer, but a kind of comfortable busy; I’ve had plenty of time to pursue new things, as well as to relax, while moving forward with plans in several different directions. I’ve been spending a lot of time studying for the GRE, which I am taking this Saturday. (GRE stands for Graduate Record Exam, which is required by many graduate programs in the US; for those familiar with other US standardized tests, it’s kind of like the SAT but for graduate school. It’s about a four hour long test of English language and mathematical ability.) Most of my studying has been brushing up on math that I haven’t needed in over twenty years, most of which I expect not to need again after the test, but so it goes.

I’ve also been working on a couple of different writing projects, one of which I am hoping to finish up before fall classes start at the beginning of September. There’s a little over a week between getting through the GRE this weekend and the beginning of the semester, and I think that will be enough time. It’s nearly done as it is, I just need to do some final edits and put together an introduction that highlights the major points.

Speaking of the fall semester, I am also excited to say that I have been working on getting a Neurodiversity Club started at my school! We had a preliminary meeting back in June to gauge interest among students who identified as neurodivergent (in whatever way), and had a great response. A couple of us then worked together to put together a proposed club constitution, which we will finalize with the larger group later this week. Then it gets submitted to the Student Activities coordinator, and if she approves it, we present it to the Student Senate in September. I’m really excited about it, because it’ll be a way to provide peer support for neurodivergent students, as well as raise the profile of neurodiversity in general.

I’m excited to be getting back to school and starting new classes, too. I did take a week off from work and most other scheduled activities last week, which was nice. I visited family for a couple of days for my birthday, and then spent a lovely week at home with my husband and dogs. We both started playing the video game We Happy Few that week, which is a fantastic (but quite dark) game with a dystopian, alternate-history setting. (It’s got this wonderfully quirky and amusing tone, though, despite the eerie and often-depressing storyline. I like the combination quite a bit.) I heard about the game from Invisible Autistic, who drew a comparison between the game mechanics and autistic masking. Having played it for several hours at this point, I completely agree with the parallels she noted.

So, busy, but mostly busy with fun and engaging things. I’m hoping to get back to a more regular blogging schedule after this weekend; I’ll at least have new classes to talk about, and stuff about the Neurodiversity Club. I think one reason I like being in school is the structure it gives to my schedule. Work does that a little bit, but my current job is so flexible that it’s not quite enough structure. But speaking of which, I need to sign off and get working for today. Talk to you later!