Introduction
More than 25 years ago, Miles et al. (Reference Miles, Haslum and Wheeler1998) described dyslexia as a syndrome that persists across the lifespan and shows itself in many other ways than poor reading. This remark sums up our perspective on dyslexia and the philosophy behind this book. We understand dyslexia to be a neurologically based syndrome – a group of symptoms including problems with reading, writing, spelling, and the procedural aspects of maths. These are the behavioural markers associated with an underlying information-processing problem related to academic skills, but we argue that the neurological basis has a considerable impact on wider areas of functioning.
As psychologists, both authors have extensive experience of conducting diagnostic evaluations for people who are finding aspects of life more demanding than they are for others. Sometimes they are individuals we have tested before, so we are in the unique position of seeing how the syndrome continues to manifest itself across the life course. Our opening question is usually ‘why do you want this assessment now?’ Those who are hoping to understand themselves better and not just seeking access to resources and adjustments refer to inconsistencies in their performance, specific examples being:
‘I have always seemed to work harder than my friends, but they get better results.’
‘I can’t remember people’s names.’
‘I can’t tell left from right.’
‘I am always late.’
‘I read slowly.’
‘I can’t remember what I have read.’
‘My spelling is awful.’
‘I run out of time in tests.’
‘I find it difficult to follow conversations when more than one person is speaking.’
‘I can tell people what I think but can’t put it on paper.’
We are interested in what creates these difficulties, not only because it is fascinating but also because it can help those of us who advise people with dyslexia improve their lives. We can think of causes as either proximate or ultimate. We know that problems with reading do not have a simple cause (a causes b), and that often a range of factors is involved. When we refer to an ultimate cause, such as the neurological basis for dyslexia, it is to attempt to identify its origin, in this case one based in material reality, something that can be measured in the brain. A proximate cause can be thought of as something just prior to the outcome, such as a problem with reading. In this case it can be the group of symptoms we call dyslexia, and then we assume it is the ultimate cause of the person’s difficulties.
If we make a mistake in attribution, it can have detrimental effects on our clients. For example, if we treat dyslexia as the ultimate cause of the reader’s difficulty, then it will depend on, for example, which definition of dyslexia we use. If that definition of dyslexia only includes reference to problems with reading accuracy and fluency, then we reach a tautological situation in which the very problem we are seeking an explanation for is repeated back to us. Question: ‘Why do you have trouble with reading?’ Response: ‘Because I have dyslexia.’ Question: ‘What does that mean?’ Response: ‘I have trouble with reading.’ This is not an unusual conversation with clients, but academic writers do not make it any clearer. In a commentary on the International Dyslexia Association (IDA) definition of dyslexia Elliot and Grigorenko (Reference Elliott and Grigorenko2024) recommend that dyslexia should be defined as ‘a severe and persistent difficulty in accurate and fluent reading’ (p. 10). So, the answer to the question ‘why do people have trouble with reading?’ becomes ‘because they have a problem with reading’. Finding ultimate explanations can be challenging, but if we understand them, we can start to realise that we cannot yet change a person’s neurological structure, but given an understanding of the outcomes that result from this, we can advise on strategies they can use to work around their difficulties.
It has been suggested that of all learning disorders dyslexia is best understood (Pennington et al., Reference Pennington, McGrath, Peterson and Peterson2019). In the ensuing chapters it will be evident that this is true to some extent, but it will also be clear that there is much misunderstanding. There is little consensus concerning definition, muddled language, and confusion between correlation and cause. The much-cited Rose Review prepared in the United Kingdom defined dyslexia as ‘a learning difficulty that primarily affects the skills involved in accurate and fluent word reading and spelling. Characteristic features of dyslexia are difficulties in phonological awareness, verbal memory, and verbal processing speed. Dyslexia occurs across the range of intellectual abilities’ (Rose, Reference Rose2009, p. 10). We will return to the last sentence later but point out here that it is contrary to the original notion of specificity. The latter acknowledges that individuals have mostly average to better-than-average intellectual abilities, but have cognitive weaknesses in areas that undermine performance and differentiate those who have specific disorders such as dyslexia from those who have a general learning disability (Kirk, Reference Kirk1962). A person who has a general learning disability will show some of the characteristics associated with dyslexia, particularly involving information processing, but they will also have many more problems. If all we do is focus on the difficulties linked to dyslexia, we cannot distinguish between the general and the specific. Essentially, it is the difference between people who have trouble learning some things and those who have trouble learning most things. To suggest that people experience the latter raises expectations that they will not be able to fulfil and is contrary to the effort that has been made to disassociate dyslexia from low intelligence. The Rose Review definition also confuses skills and abilities. The former are empirically traceable behavioural performances that are about application rather than abilities. The latter are cognitive capabilities that are theoretical constructs, so cognition is not necessarily about application (Scerri & Will, Reference Scerri and Will2023). Reading and spelling are skills, things that can be learned, acquired, and taught. Phonological awareness, verbal memory, and verbal processing speed are abilities. They are innate, probably not teachable, although they can be addressed through strategy development. The simplest model is that our skills are built upon the foundation of our abilities.
The literal meaning of dyslexia from Greek is a difficulty with words. One of the early pioneers in the field (Critchley, Reference Critchley, Pavlidis and Miles R1981) acknowledged that dyslexia is a difficulty in the use of words, how they are identified, what they signify, and how they are handled in combination, pronounced, and spelled (p. 2). He considered it to be more than a reading or spelling problem. Snowling (Reference Snowling2014) wrote that ‘current evidence places dyslexia on a continuum with other language impairments’ (p. 43). More recently, studies have revealed that even high-achieving individuals with dyslexia can have impaired oral language skills (Bradshaw et al., Reference Bradshaw, Woodhead, Thompson and Bishop2021). At the least, therefore, we need to consider dyslexia to have an impact on both verbal and written language skills.
Consider how we learn to use language in all human societies. Almost everyone learns to produce language, unless there are neurodevelopmental reasons for them being unable to do so. This most often involves the production and comprehension of abstract sounds, but it can also involve visual communication in the form of sign language. It typically begins in the second year of life (late infancy) with single words and develops rapidly into multi-word sentences. This development has the appearance of automaticity because we can observe that children are not explicitly taught to speak. We understand now that from birth, and possibly before, infants are acquiring an understanding of the fundamental building blocks of their native language: the phonemes (sounds) and grammar (structure). In developmental psychology it is said that comprehension precedes production, that children often know and understand much more than they can demonstrate. This is certainly the case with the ability that is language learning.
Contrast this with literacy learning. No one has ever learned to read and write passively. It is an active process that involves linking the phonemes and the grammar of the language to a visual form. It is reversible in that we call writing encoding and reading decoding. The ‘coding’ part is important because this is the written form of the language, and symbolism is so fundamental to humans that we have been referred to as Homo Symbolicus (Deacon, Reference Deacon1998). Literacy skill development is active and difficult, but it is built upon language ability. It is a complicated skill to acquire because it has multiple sub-skills, including the phonological, orthographic, and semantic levels of language (Seidenberg, Reference Seidenberg2017).
People with dyslexia display inconsistencies; we still do not know enough about the frequency of these or the extent to which they fall outside what Kahneman has called ‘the valley of the normal’ in which there are no surprises or inconsistencies (Kahneman et al., Reference Kahneman, Sibony and Sunstein2021). There are insufficient contemporary large-scale surveys addressing their occurrence, either amongst the general population or those who have identified specific learning disorders such as dyslexia. Too much research relies on qualitative data, often referred to as ‘lived experience’. We can learn much from the insider perspective (Reiff et al., Reference Reiff, Gerber and Ginsberg1993) but must acknowledge that it is just that, and individuals’ experiences, both positive and negative, will vary greatly and cannot be tested or refuted. It belongs to identity theory, the narrative being an internalised story created about oneself or one’s personal myth (McAdams, Reference McAdams, Schwartz, Luyckx and Vignoles2011). Personal stories ‘are understandable, memorable and naturally integrated with intuitive reasoning. They are more compelling than statistics’ (Redelmeier et al., Reference Redelmeier, Etchells and Najeeb2025, p. 5). Dressing up lived experience as phenomenology (Pathak, Reference Pathak2017) does not improve matters as the nature of the latter is that it ‘finds things’ and is subject to confirmation bias. Even one of the bellwethers of phenomenology, Jean-Paul Sartre (Reference Sartre1971), acknowledged that it will never converge with empirical science. It belongs to philosophy rather than scientific psychology. Relying on description and definition by the activist core and the disgruntled will not do (see, for example, Cameron, Reference Cameron2024). It has been suggested that postmodernists’ arguments for reducing uncertainty or approximating truth are apparently non-existent, and their method of reducing uncertainty seems to rely solely on the supposed truth of personal experience or authoritative pronouncements. The aphorism ‘the plural of anecdote is not data’ should be acknowledged when considering reports of qualitative research, as they can misinform. At best, ‘lived experience’ might generate hypotheses that can be tested through systematic empirical studies. Anyone who has spoken to an adult who has dyslexia could not exclude the impact on spelling from its description and definition. It is often the problem they identify as having caused them the most embarrassment.
In distinguishing between science and pseudoscience, Popper (Reference Popper1963) argues that the criterion for the former is its falsifiability. That is, a scientific theory should be testable, and it should be clear how it could be disproven. The perceptions of the experiences of individuals cannot be refuted. In schema that have been developed to rate the quality of research on which evidence-based practice should rely, lived experience research is the lowest (West et al., Reference West, King, Carey, Lohr, McKoy, Sutton and Lux2002). In addition, and possibly more dangerously, the accusations of those holding these views that any questioning of their ‘theories’ is ableist, colonialist, supremacist, or whichever ‘ist’ is currently most fashionable on social media seeks to end debate, inquiry, and the discovery of ultimate causes that could help people with dyslexia and other specific learning disorders. It has been suggested that the implications of cultural and cognitive relativism have been severe, negative, and poisonous for the field of special education (Kauffman & Sasso, Reference Kauffman and Sasso2006).
Models in Science and Psychology
It has become commonplace to refer to science as if it is a body of irrefutable knowledge, whereas it is a method or process. It operates on models of reality, theoretical concepts that attempt to account for phenomena and in the case of psychology explain behaviour or atleast establish probable causality. Theories only predict probabilities and should be supported by and refined based on data from systematic research. Rovelli (Reference Rovelli2018) wrote that ‘we need to adapt our philosophy to our science, and not our science to our philosophy’ (p. 118). Scientists conjecture ideas and consider their refutation. Immanuel Kant has been paraphrased as writing that ‘concepts without data are empty; data without concepts are blind’ (Guyer & Wood, Reference Guyer and Wood1998). It is suggested here that the continued focus on skills such as reading accuracy has led to research findings becoming data without a concept.
Dyslexia research has gathered findings related to reading without consideration of the bigger picture. It is driven by the pressures in modern academia to produce ‘output’ that will help achieve personal and institutional goals linked to publication counts. ‘Publishing in higher-tier journals is easier when the story is simple, and doing so can quickly turn into a citation goldmine if the field invests in challenging your theory’ (Astle & Fletcher-Watson, Reference Astle and Fletcher-Watson2020, p. 242). The pressure to publish might also account for the contrary opinions concerning dyslexia espoused by the same author in different papers and books. Much research is confirmatory, results supporting existing theories concerning the cognitive abilities associated with literacy. The notion of a core-deficit persists, a weakness in phonological processing being thought to be the cause of reading accuracy problems, confusing correlation with causation. The latter implies the former, and its ‘contrast with mere correlation is the lifeblood of science’ (Pinker, Reference Pinker2022, p. 246). Furthermore, there has been insufficient inference as to how the cognitive processes associated with reading might have an impact on other aspects of behaviour, leading to pseudoscientific notions of types of dyslexia such as ‘naming dyslexia’, referring to word-finding problems, ‘directional dyslexia’, which describes being unable to distinguish between left and right, and ‘stealth dyslexia’, referring to hidden difficulties that are not evident until demands increase at times of transition. Even within reading research it has been suggested that we should distinguish between specific reading comprehension deficit (S-RCD) and dyslexia (Barquero & Cutting, Reference Barquero and Cutting2021). If dyslexia is reframed as a problem with information processing, the links with literacy skills become clearer, and other difficulties make more sense within the context of what we already know.
Although it is usually referred to as developmental dyslexia, the emphasis on reading research has often failed to acknowledge the ‘developmental’ aspect, that is, human beings’ neurological, cognitive, emotional, intellectual, and social capabilities over the course of a usual lifespan. Even if we just focus on reading, it is important to acknowledge neuroplasticity, changes in cognition, as well as different stages and demands. From preschool age to eight years, children are learning to read. Between ages 8 and 11, they should be reading to learn. In adolescence, reading skills should be established so a student can learn how to learn, and in adulthood they should be independent learners. The cognitive weaknesses associated with dyslexia and their consequent behavioural expression are therefore of significance at different ages, so research has not sufficiently reflected the broader perspective advanced by Miles. For example, phonological awareness ‘seems to be a minor problem in adulthood’ (Reis et al., Reference Reis, Araújo, Morais and Faísca2020, p. 365). It might be important when a child is learning to read, but not when as an adult the same person is trying to understand and absorb complex material associated with a course of study or occupation. In a recent edition of the Oxford Review of Education devoted to dyslexia, Miles’ work is eulogised in one paper (Evans, Reference Evans2020), but definitions in others are still focused on literacy, particularly word decoding and spelling fluency (Snowling et al., Reference Snowling, Hulme and Nation2020). Furthermore, in an American paper titled ‘Solving the problem of learning disabilities’ (Siegel, Reference Siegel2019), it was suggested that what is required to confirm whether or not somebody has a learning disability such as dyslexia is to assess their reading, spelling, mathematics, and perhaps writing. In other words, to just establish behavioural characteristics such as academic attainments, without reference to the cognitive-processing difficulties that are neurologically based and undermine the acquisition of skills beyond literacy and numeracy.
The real problem with ‘learning disabilities’ is ‘learning’ and the focus on academic skills. Successful people with dyslexia often learn very well but have worked harder at developing skills and rely on means others do not have to depend upon. They are often inappropriately described as ‘compensated dyslexics’, but this only refers to reading accuracy and has been an unconscious rather than a deliberate process. It is their performance in academic skills that is undermined, not their ability to learn. The criterion of poor reading, it has been argued, can only be applied between the ages of 5 and 14 years because a child can’t be a poor reader before the former, and by young adolescence many can read adequately even though they did not start well. Miles et al. (Reference Miles, Haslum and Wheeler1998) wrote that ‘it would make for better communication if those who want to limit their studies to reading did not use the word dyslexia at all’ (p. 48). Nevertheless, the focus on literacy persists, for example, Snowling et al. (Reference Snowling, Hulme and Nation2020) proposed that the term dyslexia should only be used to refer to a difficulty with decoding and spelling fluency that is persistent over time and affects academic functioning in literacy-based areas of the curriculum. Further, in a recent paper that attempts to clarify the conceptualisation of dyslexia, the emphasis remains on the acquisition of accurate and/or fluent reading, spelling, and comprehension (Wolf et al., Reference Wolf, Gotlieb, Kim, Pedroza, Rhinehart, Tempini and Sears2024).
The focus here is a lifelong perspective, as it is only when we acknowledge that syndromes such as dyslexia persist throughout life, not necessarily at a literacy level but as a processing difficulty that undermines a range of skills extending beyond the academic, that we will come to understand them. There is, therefore, a need for conceptual models of dyslexia that address all its manifestations, especially as there has always been a socio-political agenda surrounding the concept, and inevitably in the United Kingdom some of the criticism is class based. Journalists and politicians, usually ‘critics with a credo’ to use a phrase from Auden (Reference Auden2005), have questioned the concept. Much of this has been based on a misunderstanding of nuanced debates about reading difficulties, leading to the conclusion that ‘dyslexia does not exist’, the work of academics opposed to the concept that emphasises disagreement cited in support (Elliott & Grigorenko, Reference Elliott and Grigorenko2014, Reference Elliott and Grigorenko2024), whereas a theory should rest on evidence in favour of it, not just evidence against it (Shermer, Reference Shermer2018). Rather than improve the understanding of those who find life more demanding than others, the consequence has been the denial of resources and increased anxiety amongst people with dyslexia.
Based on the existing scientific literature and an analysis of our archive data, it is our view that dyslexia’s ultimate cause is an inherited neurological inefficiency resulting from differences in brain structure and connectivity that leads to a significant deficit in the information-processing ability known as working memory (see Chapters 3 and 4). The overwhelming evidence for this proposition derives from work with children as well as adults and helps explain why this persisting weakness in working memory has a significant impact on literacy skills, as well as other behaviours.
Labels
Many papers have been devoted to the use of labels in the field of learning disorders and often adopt a negative perspective, suggesting that they can undermine self-efficacy beliefs (Jodrell, Reference Jodrell2010), but ‘we cannot avoid labels because we must have words to describe things, including the characteristics of the people we encounter’ (Kauffman, Reference Kauffman2007, p. 246). Contrary to the postmodernist rejection of the idea that words cannot refer to anything, we accept that if something has a name it exists, and our world is defined by the words we use. A word ‘gives origin to all things’ (Momaday, Reference Momaday1987, p. 33). We might argue about their nature and should refine meaning according to increased understanding. Regarding dyslexia, the much-cited adage ‘the absence of evidence is not evidence of absence’ (Sagan & Druyan, Reference Sagan and Druyan1997, p. 213) certainly applies. ‘Science is not reliable because it provides certainty. It is reliable because it provides us with the best answers we have at present’ (Rovelli, Reference Rovelli2018, p. 232). The objective data from neuroscience and cognitive science that helps us understand dyslexia in all its manifestations has grown substantially and is increasing all the time (Ramus, Reference Ramus2014). It cannot be ignored, but if research findings are to make sense, clarification of the concept is necessary.
Dyslexia, unlike terms for general learning disorders, has avoided what has been termed the euphemism treadmill (Pinker, Reference Pinker2003) of constantly changing terms for the same core concept. However, this has not prevented dyslexia itself being categorised under a range of different labels such as ‘challenged’, ‘gifted’, and ‘neurodiverse’. People with dyslexia experience difficulties that are ultimately due to them having lower-functioning working-memory capacity because of neurological differences. They are not challenged, dyslexia being an inherent product of their neurology, not an external factor, although the demands of education and employment highlight their difficulties. They are not gifted because they have dyslexia, although they may well be gifted despite it. They are no more or less diverse than any other group of people; however, they are distinct in the ultimate cause of their difficulty. Kauffman (Reference Kauffman2007, p. 246) has written that:
People soon figure out the euphemisms we use for the phenomena we call disabilities, failure, or superior achievement. Referring to a disability as a challenge sets up people with disabilities for eventual ridicule. Euphemisms fool no one for very long, but they do confuse communication for a while and ultimately make whatever we are referring to appear more negative or less worthy of respect than the original term.
We do not need new language and terminology but a clarification of what we mean by dyslexia, its origins and impact, if we are to help people find solutions and work towards achieving their academic, occupational, and life goals.
Summary
The main points of this chapter, in which we have established the tone for the rest of this book, include:
questioning the continued focus of dyslexia research on reading;
placing dyslexia within the context of it being a neurodevelopmental disorder;
stressing that dyslexia has an impact on cognitive functioning, so it is a broader syndrome that affects many behaviours;
promoting an empirical, evidence-based approach to understanding and defining dyslexia that explains all the inconsistencies in a person’s performance;
emphasising a lifelong perspective;
criticising the use of euphemisms to refer to learning disorders such as dyslexia rather that clarifying the concept.
