Author’s Note: I no longer particularly like some of the ideas in the post, which I now think are a bit oversimplified. If you want an updated take on my view of neurodiversity, I wrote an article at https://doi.org/10.1159/000523723.

In Part II of this series, I discussed a lot of the basic ideas that still motivate my approach to neurodiversity.  I argued that we presently lack a clear, consistent definition of neurodiversity, and I illustrated how this ambiguity hinders our efforts to bridge gaps between groups with conflicting views on the neurodiversity paradigm.  Those who are skeptical of neurodiversity might focus on the most radical ideas and rhetoric coming from autistic advocates, and any shortcomings in these radical ideas would only confirm their worst fears about the neurodiversity paradigm.  Conversely, those advocates who embrace neurodiversity might adopt more practical, nuanced definitions of the neurodiversity paradigm and more radical definitions of the opposing medical/pathology model.

However, in Part II, I also tried¹ to bring some clarity to the situation.  I focused mainly on demonstrating that (contrary to common fears) attempting to change the individual is possible within the neurodiversity paradigm.  I tried to show that we don’t really need to call someone “deficient” or “disordered” to change them²: we simply need to recognize that it would help them thrive, be happy, and enjoy better mental well-being if they possessed some skill.³  However, while it’s important to retain the ability to teach skills to the individual, we’ll often find that changing the environment around the individual is going to be more effective in promoting their well-being, something which the medical model doesn’t help us with.  Furthermore, if we’re going to strive to help the individual thrive and be happy, whether we do so by trying to change the individual or their environment, we probably don’t want to insult them and say that their mind and brain are fundamentally “deficient” and “disordered.”⁴

Notably, I stopped short of proposing a full, complete definition of the neurodiversity paradigm in Part II.  After I wrapped up the argument showing that the neurodiversity paradigm does not stop us from empowering individuals by teaching them skills, I simply noted that the neurodiversity paradigm also has the advantage of allowing us to investigate how society interacts with neuro-divergent people, before I concluded with a brief discussion suggesting that the neurodiversity paradigm does apply across the full breadth of the autism spectrum, including to those with co-occurring intellectual disabilities.⁵

Nearly a year has now passed since I finished Part II.  If I’m remembering correctly, I think I felt some trepidation about providing a full definition of the neurodiversity paradigm at that time: I think I felt it was a little presumptuous to claim, after only one year of graduate school,⁶ that I was the person to provide a definitive encapsulation of what I regard as one of the most important transformative ideas in human history.  Perhaps it is still a bit presumptuous for me to offer a definition,⁷ but I have realized that I do need to provide one anyway.  The panelists and speakers at our Neurodiversity Summit at UC Davis last month reminded me once more of the many reasons why the neurodiversity idea is so vitally important in our real-world communities, and I was also encouraged by the way we were able to use that event to reach out to a broad audience of self-advocates, parents, researchers, and professionals.  The event reinforced my belief that much greater consensus would be possible, if we could only reach across divides between different communities and speak in a common language⁸ with clear understandings of what the terms and concepts we use actually mean.

So, what is neurodiversity?  First of all, we need to distinguish (as suggested by Nick Walker) between different senses in which the term “neurodiversity” is employed, which I will describe as the fact of neurodiversity, the neurodiversity paradigm, and the neurodiversity movement.  The fact of neurodiversity is quite simple: the term “neurodiversity” refers to diversity of minds and brains, a type of diversity that we know exists as a matter of fact.⁹ Meanwhile, the neurodiversity paradigm is a specific model for understanding and responding to this diversity; it can be thought of as a rival of the social and medical/pathology models.  Finally, the neurodiversity movement is a loosely organized social movement that seeks to promote widespread adoption of the ideas contained within the neurodiversity paradigm (although some of its members may, of course, have additional goals).

And just what is the neurodiversity paradigm?  What is this model for understanding neurological diversity?  I would like to propose that there are three major ideas contained within it, specifically:

1. the idea that there is no single, perfect ideal of what a human mind or brain should be: that, on the contrary, the existence of diversity of minds and brains is necessary for human societies to flourish;
2. the idea that autistic and other neurodivergent people should be accepted for who they are, and that making neurodivergent people more “normal” should never be pursued as an end in itself; and
3. the idea that the challenges and barriers faced by neuro-divergent people cannot be solely attributed to internal differences or “deficits,” but that these challenges can reflect problems in the ways that human societies interact with neuro-divergent people.¹⁰

Idea One: No Ideal Minds or Brains

In a sense, this is the most obvious idea contained within the neurodiversity paradigm.  The fundamental core of the neurodiversity approach seems to be the notion that diversity of minds and brains is a good thing, not something to be squashed and suppressed.

However, while the basic idea is clear, the nuances of how it should be applied and interpreted are most definitely not clear.  Does the neurodiversity paradigm truly mean that any and all minds and brains are good?  What about a mind/brain system that makes somebody injure themselves – which is inherently harmful to them?  How about a mind/brain system that is incapable of developing language and communication – how is that valuable?  If we developed a mind/brain system that made people walk themselves off cliffs without regard for their own safety, would that too be good?

Clearly, if we followed the idea that all diversity of minds and brains is good, or if we believed that we should always strive to maximize diversity of minds and brains, we would find ourselves deep in the land of absurdity.  If it were true that the neurodiversity paradigm meant we should always strive to maximize diversity of minds and brains, this would indeed be good reason to reject it.¹¹ Fortunately, I do not think the neurodiversity paradigm entails such nonsense.

If we think about the origin of the neurodiversity idea, it was inspired by the idea of biodiversity.  Judy Singer, who coined the term, makes this clear in her thesis:

“Why not appropriate metaphors based on biodiversity, for instance, to advance the causes of people with disabilities? Why not propose that just as biodiversity is essential to ecosystem stability, so neurodiversity may be essential for cultural stability?”

Do those who believe in the necessity of biodiversity typically spend their time advocating the use of genetic engineering to deliberately maximize variation within and between species in our natural environments?  Do they propose, for example, that every single individual organism should be genetically engineered into its own species, solely for the purpose of maximizing biological diversity?  Interestingly, they do not.  Biodiversity advocates do not appear to believe that maximum or infinite biological diversity would be a good thing.  Instead, they appear to operate under the sensible assumption that there is some desirable and healthy level of biological diversity that makes an ecosystem function well.

Perhaps the neurodiversity paradigm, then, can be understood in similar terms.  Clearly, if everyone in the world had an identical mind/brain system, human society would not function well at all!  A complex society such as ours needs people interested in and suited for the countless thousands of different occupations, roles, and fields that exist in it.  Thus, some level of neurological diversity is very clearly a good thing.

Still, this leaves us with a major unanswered question.  If there is some desirable level of neurological diversity in a society, and by extension some undesirably limited or excessive levels, what does that mean for individual neurodivergent people?  Is there still some sense in which we should seek to eliminate “excessive” neurological diversity by normalizing people?

Idea Two: Acceptance, Not Normalization

In fact, the idea we should normalize people to eliminate “excessive” neurological diversity does not seem to be all consistent with the neurodiversity paradigm.  On the contrary, it clearly runs against the ideals expressed by neurodiversity advocates and researchers such as Damian Milton, who argues that efforts to normalize people are psycho-emotionally disabling, or Jim Sinclair, who passionately pleads for parents to accept their autistic children, warning that non-acceptance of autism effectively tells autistic children that their parents wish they would cease to exist and be replaced by different, neurotypical children.¹²  The works of neurodiversity advocates often emphasize that efforts to normalize the neurodivergent individual can be inherently damaging to mental health, self-esteem, and self-acceptance.

This is why I believe that the distinctions between deficit and the proper target of intervention, between normalization and the teaching of skills, are of such vital importance.

In my opinion, we can and should jettison the medical/pathology model’s idea of deficit.  I honestly believe it serves no useful purpose.  Firstly, as I argued elsewhere, it’s very difficult to definitively state that something is a deficit: that it is a problem located within the individual, to which the individual’s environment does not contribute.  (It therefore follows that it’s very difficult to definitively state that any given neurodivergent individual constitutes “excessive” neurological diversity that is undesirable and that should be eliminated.)  Secondly, even if we were able to conclude that some given disability was caused by an internal deficit, this would have no bearing whatsoever on how we intervene to address the challenge.

What do I mean by that?  Well, this is what I was focused on in Part II: showing that our decision to intervene by changing the individual or their environment depends solely upon which will best help the individual to be happy, to thrive, and to have good well-being.  One factor that certainly affects well-being is the degree to which the neurodivergent individual is able to make choices about what interventions are used to address barriers they face: if the individual is not happy with an intervention, it is unlikely the intervention will make them happy!  In contrast, and counterintuitively, one factor that is not necessarily relevant is whether the problem is ultimately located within the autistic individual or within the environment around them.

Let us consider an example.  I have never been particularly pleased about sensory distress in autism.  Sure, there are ways in which autistic sensory and perceptual processing can be advantageous, but sensory distress itself is inherently distressing.  Furthermore, sensory distress is based on neurobiological processes within the individual, so I believe it has a decent claim to being both internal and inherently bad: i.e., a deficit.¹³ But be that as it may, we’re probably not going to be able to successfully intervene to address sensory distress by neurobiologically changing the individual.¹⁴ Our most effective solution for dealing with this apparent internal deficit will probably be altering the sensory environment around the individual, either by directly manipulating the sources of the sensory stimuli or by interposing a technological barrier between the individual and their environment.

Not convinced yet?  Let’s try the example of self-injurious behaviours like head-banging.  Are they located within the individual?  Yes: they reflect brain-generated motor responses.  Furthermore, the self-injuring behaviours are clearly inherently harmful to the individual.  Now, how might we intervene to stop it?  Not by trying to directly change the individual’s motor responses, but by looking in the environment to see if we might be able to identify and reduce any factors (like stressors) that could be associated with the behaviour.

Here’s another example: language.  If someone doesn’t learn language automatically, there’s likely something about their brain that’s causing the problem.  I also think there’s also a good case to be made that communication is an inherently good and useful thing, and that lacking it is inherently bad.  However, our best intervention in these cases might be an augmentative and alternative communication system, which allows for communication but in a decidedly non-normal way.  I think one could argue that AAC is primarily concerned with altering the environment to facilitate a new type of communication.¹⁵

Does it work the other way – that sometimes the best way of dealing with an environmental problem is to change the individual?  I wish I could say no, but I must bow to reality.  Today, at least in formal interventions,¹⁶ we’re probably much too quick to dismiss the possibility of changing the world and to resort to changing the individual, but there are sometimes cases where changing the environment may simply be impractical.

Thus, there is no straightforward, one-to-one correspondence between the existence of deficit and our decisions about whether to intervene by changing the person or their environment.  The idea of deficit is not only damaging to mental health, but it does not aid us in identifying the correct intervention approach.  Furthermore, I believe access to supports should be based on the presence of disability, not deficit, and I believe that neurotypes can be defined based on individual characteristics without necessarily imposing the need for us to describe those features as deficits.¹⁷

An attentive reader may, however, be asking why I am even presenting the idea of changing the person as an option.  After all, only a few paragraphs ago I was emphasizing the importance of accepting the neurodivergent person instead of trying to normalize them!  This is where we come to our second vital distinction – the distinction between normalization and the teaching of skills.

Normalization is about trying to make neurodivergent people neurotypical.  It is very explicitly based on the idea that there is something wrong with being neurodivergent, and this message is not at all conducive to good mental health or general well-being.  Normalization has also tended to be fairly ineffective.  Although normalization has been our society’s main approach to neurological diversity for some time – not only through formal interventions, but also through simple yet staggering social pressure for conformity – it has obviously been unable to achieve its apparent aim of making neurodivergent people into neurotypicals.  It may be particularly difficult to normalize non-speaking people, or people with intellectual disabilities, or others who lie somewhat farther from neurotypical development.¹⁸  For this reason, many of us have been compelled by necessity to stray from the pathology model and the normalization approach, and to instead focus on adapting environments to accommodate neurodivergent people.  Furthermore, and alarmingly, many autistic advocates report experiencing fatigue and distress as a result of attempting to appear more normal by camouflaging their autistic features.  Thus, not only does normalization typically involve damaging rhetoric, and not only does it tend to be rather ineffectual, but normalization itself might sometimes be harmful.  Normalization is therefore not at all desirable as an end in itself.

However, this does not mean that changing the individual is inherently undesirable.  Indeed, teaching neurotypical and neurodivergent people new skills may be a positive thing, if it empowers them to succeed in the world and makes them less dependent on others.

Neurotypical children automatically learn spoken language, but they generally require some instruction before they learn mathematics or reading.  This is something our society expects, and governments have accordingly developed systems of public education that aim to teach children mathematics and reading (and much else besides).  We do not tell children who are too young to have learned math or how to read that they are deficient, because we recognize that expecting them to learn math and reading at that age would be unreasonable and that calling them deficient because of it would be as unnecessary as it would be cruel.  Nor do we expect young children to behave as though they were adults, because we recognize this would, again, be cruel and unsuccessful.

Now, I don’t want to give the impression that I regard neurodivergent adults as children in need of paternalistic protection and care!  On the contrary, we will be most successful in promoting the happiness and well-being of individual neurodivergent people when we respect them and when we ensure that they can exercise the power to make choices about their lives.  My point is only that we can and do teach people skills, empowering them, without needing to invoke ideas of deficit, pathology, and normalization.  Indeed, we are probably going to be more effective in teaching people skills when we refrain from bringing in ideas of deficit and normalization.  This is why my definition of the neurodiversity paradigm claims that normalization is problematic, yet it says nothing to exclude all attempts to change people by teaching them skills.

There are many ways that we might teach skills without bringing in ideas of deficit.  To give one example from my own experiences, I learned a lot about social skills through a theatre program for autistic students, even though (or because) the organizers of this program very explicitly rejected the idea of making the program a therapeutic one.  As a result of their decision, I enjoyed the program much more than I would have if it had been set up as a way of helping me with my “deficits.”  It’s perfectly possible for neurotypical clinicians and professionals to set up other programs on similar lines.  I’m also a big believer in autistic communities and autistic mentorship: I think we not only have some unique insights to offer one another about the challenges and barriers we can face, but that we’re particularly good at providing this advice without reducing one another to an inferior role.

Idea Three: The Role of Society

Finally, I believe there’s one more major component to the neurodiversity paradigm.  As we’ve seen, the neurodiversity paradigm rejects the idea that deficit is located solely within the individual.  It may not deny that the individual can be involved – Judy Singer’s original thesis presenting the idea of neurodiversity stopped well short of claiming that all challenges were constructed by society – but it does direct our attention to the possibility that society could be involved as well.  Perhaps society neglects and ignores neurodivergent people.  Perhaps neurotypical people sometimes struggle to have empathy for neurodivergent people, and perhaps neurotypical people sometimes hold rigidly to fixed customs when neurodivergent people could benefit from some flexibility.  Perhaps there could be social oppression and discrimination against people with disabilities, including neurodivergent people.  To explore these possibilities, we need to not only study neurodivergent people, but also neurotypical people and social institutions, and we need to be prepared to undertake social reforms in response to our findings.

The medical/pathology model does a very poor job in this area.  In the medical model, the neurotypical person is held up as the ideal.  Not only are neurodivergent people supposed to strive to become more neurotypical, but the neurotypical person is simply not a subject of study.  Neurotypicals appear in experiments only as controls against which the performance of neurodivergent people can be measured (and perhaps found wanting).  Indeed, researchers and clinicians following the medical model evidently feel no reservations about making sweeping and highly subjective judgements about the disorders and deficits of others.

Bad things tend to happen when any one group – however well-meaning or well-intended its members may be – is in a position of power over another group.  Bad things may be especially likely if the powerful group has control over the narrative about the less powerful group.

To deal with these dangers, we need to ensure that there is ample contact between different groups, such as parent-advocates, neurodivergent advocates, and researchers – and not just any contact, like brief interactions between researchers and participants in their studies,¹⁹ but prolonged and sustained contact in which the different groups have relatively equal power, in which they approach one another with openness, and in which they come genuinely prepared and willing to make changes.  Through such contacts, we can continue to reform research, clinical practice, and social institutions to incorporate the insights offered by the neurodiversity paradigm.

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1. Like others such as Emily Page Ballou and Aiyana Bailin, whose articles on the subject I recommend.
2. Crucially, the ideas of deficit and disorder are independent from the idea of disability.  To me, “disability” merely refers to challenges and barriers that have a negative effect on well-being, such as by reducing one’s efficacy and power in the world.  This disability could be caused by deficits in the individual, flaws in the society around the individual, or (as I prefer to think of it) an interaction between the individual and their environment.  Thus, we can still identify people who are encountering barriers and challenges, which is necessary both to empower people with self-knowledge and also to conduct proper gatekeeping to ensure that supports go to those who need them.
3. Neurodiversity advocates probably mostly focus on one problem faced by the autistic community: that formal interventions for autism are overwhelmingly and explicitly biased towards changing us, sometimes to the extent that the appearance of normality, or a reduction in our apparent autistic features/“symptoms,” is a goal of the intervention in and of itself, independent of our actual happiness and well-being.  This is indeed a serious problem, but I also believe that we face another problem, which is the way we are not being adequately prepared for greater independence, particularly in adulthood.  Often this is because people around an autistic individual will do things for that autist, preventing them from developing skills that they will need in adulthood.

   At first, these two ideas might seem to be contradictory – first I’m saying we need to do less to change individuals and more to change the contexts around them, but immediately afterwards, I say we need to stop doing things for autistic people (changing the context around them) and start allowing them to learn new skills (changing them).  However, I think both statements are true in different contexts:

   Often, when we’re focussing on trying to change the autistic individual, it’s in the context of a formal intervention program: something like early behavioural intervention or social skills training.  We need to dramatically change the way we do these formal interventions to focus more on how we can adjust the environments around neurodivergent people, and we also need to change our language and assumptions so that they are less demoralizing to neurodivergent people.  Furthermore, we need to change the broader societal pressures that demand conformity and normality, as these pressures can make autistic people feel compelled to effortfully camouflage their own autistic features.

   On the other hand, when we’re going ahead and doing things for autistic individuals, it’s probably in the middle of regular life when we’re just trying to get through the day with minimal fuss.  Teachers and parents might, for example, constantly prompt the individual to finish their work, preventing them from developing independent motivational and organizational skills.  Of course our goals need to be realistically within the individual’s potential, and we need to be wary of causing excessive stress and burnout, but within those constraints, I do believe that we can and should do more to ensure that neurodivergent people are empowered with the skills they need to succeed in life.

4. It later occurred to me that much of what I had written was somewhat paternalistic in tone: it seemed to imply that choices would be made by some objective, impartial, probably-neurotypical expert.  This was a mistake, because I strongly believe that autistic people need to be empowered to make many of these choices for themselves.  Right now, when autistic people access services and supports, they often do so as petitioners, asking an expert neurotypical to generously offer their expertise to help the autistic person with their deficits and challenges.  Furthermore, the services and supports that are offered are usually imperfectly matched to the individual’s needs.  Thus, this process is not only disempowering, but also inefficient.
5. I later wrote a separate post more explicitly focused on that issue.
6. Moreover, graduate school in scientific psychology, not a field like philosophy, political science, or sociology that might make one more qualified to write about ideas like neurodiversity!
7. And if so, I doubt the extra intervening year of graduate school has made much difference…
8. We should, of course, endeavour to make this common language nonstigmatizing and inoffensive to all parties. We should also defer to those in a group when we choose a term to define the group.
9. To avoid confusion, I will ordinarily refer to this as “diversity of minds and brains” or “neurological diversity.”
10. In this definition, it should be noted that the neurodiversity paradigm contains both empirical and normative claims.  The paradigm not only seeks to describe the world, but also to dictate a proper way of responding to the world.  In this regard, it is no different from alternative paradigms like the medical model, which not only describes neurological diversity as disorder but dictates that the appropriate response to diversity of minds and brains is its elimination through normalization.
11. I should be clear, though, that this would be no reason to replace the neurodiversity paradigm with the medical/pathology model.  The medical model is at least as capable of being reduced to absurd extremes, as I have endeavoured to show in Part I of this series, and even more so if we were to say that the pathology paradigm means everyone should have exactly the same kind of brain.  Instead, this would be a signal that an entirely new approach is required.
12. Strictly speaking, Sinclair’s essay was written before the term “neurodiversity” had been coined, but the essay has been widely adopted as a seminal work by neurodiversity advocates.
13. And if you disagree – if you think that sensory distress or any of the other examples I deploy here are not internal deficits at all – I’ll just take it as support for my earlier claim that it’s very difficult to definitively say whether something is a deficit or not.  All I’m trying to do here is find reasonably plausible candidates.
14. I’m prepared to admit that some examples of sensory distress in autism may be more about learned associations than an inherent aversion to the sensory properties of a stimulus (e.g., loudness, pitch) – we might think of this as the distinction between misophonia and hyperacusis.  In the case of learned negative associations, gradual exposure may be effective, but if the sensory distress is caused by inherent properties of the sensory stimulus, I fear that exposure will likely backfire.  In this example, I’m focusing on inherent sensory aversions/hyperacusis.
15. Though there is clearly also some effort to change the individual by teaching the skill of using the AAC system that we have introduced into their environment.  In practice, interventions will often include a mixture of attempts to change the individual and their environment.
16. Informally, in the moment, when we’re just trying to get through the day, we may instead rush forward to adjust the environment around the person, such as by doing their schoolwork for them. This is also problematic, because it stops people from learning. See footnote 3, above.
17. Many autistic people have developed parodies of the DSM which instead describe typical development as a disorder characterized by deficits (such as pathological failure to accept neurodivergent people, or a pathological obsession with conformity, or an impaired ability to focus on intense interests).  To me, this simply emphasizes the difficulties inherent in the concept of deficit, and it emphasizes the importance of defining neurotypes using non-judgemental statements about individuals’ neural features.
18. Even though, ironically, we tend to say that the pathology paradigm fits these people better than it does verbally-fluent autistics without intellectual disabilities, who lie rather closer to neurotypical development.
19. Which occur in a study setting designed by researchers and wherein researchers have the not inconsiderable authority offered by their expertise, creating something of an unequal power dynamic.