Neurodiversity and the Ecology of Thought

Rethinking the foundations of mental disorder.

Posted Feb 13, 2021

What does it mean for a brain or mind to malfunction?

This question is at the heart of the challenge raised by neurodiversity proponents who have argued that disabilities like autism or dyslexia may in fact be "natural variations" rather than pathological conditions. 

Some scientists dismiss the neurodiversity perspective as being at odds with scientific consensus. However, I have just published new theoretical research in Perspectives on Psychological Science that provides reason to think neurodiversity proponents may have been right all along.

I did this by making two moves. First, I showed that the dominant models of mental functioning that our scientific consensus relies on systematically overlook a variety of forms of functioning, leading to a routine pathologisation of cognitive minorities. Second, I proposed a new model that both avoids these problems and supports the neurodiversity perspective. 

The Existing Debate

The dominant conception of "disorder" (whether mental or physical) defines it as "harmful dysfunction." The idea behind the "harmful dysfunction" conception is that "dysfunction" is an objective biological or cognitive impairment, whereas the "harm" component is socially mediated and associated with disability or distress.

The dominant models of mental functioning seek to be consistent with evolutionary biology and they thus focus on individual adaption or fitness. We can call these models "individual comparativist" models, since they focus on the individual and compare them to a broader functional norm. This way of modelling mental functioning leads to all humans being ranked, with people being classified as, say, "highly intelligent" or "low functioning."  

So far, neurodiversity proponents have challenged the "harm" aspect of mental disorder by drawing on social models of disability to provide an alternative to the medical model. This provides part of the theoretical basis for the neurodiversity critique by showing that the harm neurodivergent people often experience can be alleviated by changing the environment.

Neurodiversity proponents have also questioned whether our understanding of "normal" and "pathological" cognition is objective. As many have pointed out, there is good reason to think there is some arbitrariness around the way we construct normalcy in our models of mental functioning. Others point out that things like functioning labels are harmful.

However, showing that a social model can be useful for a disability does not by itself show that there is no medical dysfunction, since it is perfectly coherent for a genuine pathology to be alleviated through the use of a social model. Moreover, showing that the existing models have some arbitrariness is not enough to dismiss these models as such, since all scientific models are somewhat arbitrary.

Because of this, to make the neurodiversity perspective more convincing from a scientific perspective, neurodiversity proponents don't just have to critique the existing model. They also need to provide an alternative model that has greater utility than the dominant models.

Towards an Ecological Perspective

In the article, I took up this challenge by focusing on how neurodiversity proponents such as Judy Singer stress that human minds work more like an ecosystem than like individuals in competition with each other. There are three related points in support of this, which I reviewed the evidence for in the article.

First, different minds may have more specialised functioning that is functional in its own way, despite falling outside the norm. For instance, many dyslexic people are highly creative despite being disabled in other ways.

Second, neurocognitive diversity itself is beneficial at the group level, since the more cognitively diverse groups are, the more cognitive resources they will have for adapting to changing environments. This can mean that it is good from the group perspective to include a diversity of minds, regardless of whether some are associated with disability.

Third, which forms of mental functioning work well or not at a given time will be in large part determined by how we construct the environment. Our cognition is scaffolded by external factors, and what seems like individual dysfunction can in fact be an issue with cognitive scaffolding.

As I argued in the paper, once we take these factors into account, it becomes clear that the dominant models aren't just arbitrary. Rather, they systematically overlook or underappreciate neurodivergent functioning due to their individualist comparativist perspective.

The Ecological Model

In light of all of this, I drew on recent theoretical research on how ecologists conceptualise ecosystem functioning to develop an "ecological" model of mental functions. There are three key differences between this ecological model and the dominant evolutionary models.

First, the ecological model has a relational conception of functions and dysfunctions. Instead of locating functioning or malfunctioning inside individuals, it has room to locate it between people (as with the double empathy problem), or in the relationship between people and environment (as the minority stress model shows).

Second, the ecological model is multi-level: It takes contributions to groups into account as well as individual fitness. This allows us to recognise that cognitive diversity is often beneficial for things like group problem solving. 

Third, the ecological model is forward-looking. Evolutionary concepts of functioning tend to be backwards-looking in the sense that they define the "proper" function of a mechanism by looking to the evolutionary past. By contrast, the ecological model acknowledges that since the environment is constantly changing, we can't know what will count as adaptive in the future—and that diversity of functioning contributes to robustness in the face of constant change regardless of whether it was the product of selection. 


There is no way to know yet how many researchers will adopt the ecological model. However, since it can capture the data that is overlooked by the individualist models, there is initial reason to think it will have greater scientific utility. I end by suggesting at least three implications of the ecological model being adopted.

First, the ecological model would support the neurodiversity perspective. That is, once we move towards a relational model of functions, it makes more sense to talk about natural variation than healthy and disordered people. Of course, this doesn't deny that there are dysfunctions (or that medical intervention may sometimes be helpful), it just doesn't reduce these dysfunctions to the individual mind or brain.

Second, it could help provide part of the conceptual basis for a neurodiversity paradigm that would cultivate more space for researchers to ask different questions. For instance, instead of focusing on "deficits" in the individual, they would orientate more towards broader systems functioning beyond the individual.

Third, this model may help ground a conservationist approach to disability. From the perspective of the ecological model, cognitive diversity is constitutive of mental functioning rather than being at odds with it. Given this, there is more reason to conserve and support, rather than seek to eliminate, neurodivergence—just as neurodiversity proponents have long contended. 


Chapman, R. (2021). Neurodiversity and the Social Ecology of Mental Functions. Perspectives on Psychological Science. Online first.