Dyslexia would not be a true neurobiological disorder but an asset to human evolution

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Dyslexia was classified as a reading disorder by the World Health Organization (WHO) in 1991 and as a disability in 1993. It affects up to 20% of the general population, regardless of culture or region of the world. This percentage varies in particular according to the spelling characteristics of the language in which children are learning to read. Often perceived as lazy or with limited intellectual abilities, these children face difficulties that have long been underestimated, as does their potential. Recently, a team of American researchers put forward a new hypothesis: dyslexia is not an ordinary neurological disorder, but an evolutionary advantage. People with dyslexia would be more proficient at exploring the unknown. This probably plays a fundamental role in human adaptation to changing environments. These results thus shake our view of dyslexia.

Dyslexia is defined by the World Federation of Neurology as ” a disorder in children who, despite classical classroom experience, do not acquire language skills in reading, writing and spelling that correspond to their intellectual abilities “.

Many factors, both environmental and biological, can underlie difficulties in learning to read. It is therefore not possible to reduce all reading difficulties to a single cause or disorder. Nevertheless, research for more than a century has shown that a certain number of struggling children have severe dyslexia, despite being normally intelligent and having learned appropriately in normal family and social settings. Therefore, a specific reading disorder was hypothesized, a disorder also known as developmental dyslexia and often abbreviated as dyslexia (to be distinguished from alexia or acquired dyslexia, which occurs in adults after brain injury). .

Recently, researchers at the University of Cambridge studying cognition, behavior and the brain as a whole used an evolutionary approach to understand this phenomenon of dyslexia, which is found in all cultures. They wanted to determine the usefulness of this type of cognition and concluded that people with dyslexia would specialize in exploring the unknown. Your work will be published in the journal frontiers of psychology.

Dyslexia through the prism of evolution

The team’s hypothesis builds on that of Norman Geschwind, who noted a growing body of research suggesting that people with dyslexia have superior talents in certain non-verbal skills related to art, architecture, engineering and athletics. Ge Schnell was the first to point out a likely evolutionary basis for the observed differences. Furthermore, he suggested that when a relatively large proportion of a population is in what appears to be an unfavorable condition, ” It’s worth considering whether there might be a compensating advantage at play “. Not to mention that this disorder affects multiple genes and is said to have a heritability of at least 60%.

In addition, the researchers are based on a brand new theory of evolution by the same team at the University of Cambridge. The latter proposes that successful adaptation in humans results from collaboration between individuals specialized in different but complementary neurocognitive research strategies. In other words, the complementarity of individual intelligences is key to the evolution and survival of the human species.

In the present study, the authors examine the cognitive differences associated with dyslexia from an evolutionary perspective through an interdisciplinary approach by reviewing all currently available scientific literature.

dr Helen Taylor, a researcher affiliated with the McDonald Institute for Archaeological Research at the University of Cambridge, said in a statement: ” The deficit-centric view of dyslexia doesn’t tell the whole story. This research provides a new framework to help us better understand the cognitive strengths of people with dyslexia “.

Complementary cognition underpins dyslexia and our survival

As previously mentioned, the new theory developed by Taylor and his colleagues that supports the findings about dyslexia posits that our ancestors evolved to specialize in distinct but complementary ways of thinking, reflecting human ability enhanced to adapt through collaboration.

Furthermore, these cognitive specializations are rooted in a well-known trade-off between exploring new information and using existing knowledge. Exploration includes activities that involve searching for the unknown, such as experimentation, discovery, and innovation. In contrast, exploitation involves the use of what is already known, including refinement, efficiency, and choice.

The authors use a concrete example: If you eat everything you have, you could starve when it’s gone. But if you spend all your time looking for food, you’re wasting energy that you shouldn’t be wasting. “. As with any complex system, one must balance the need to exploit known resources and explore new resources in order to survive.

Taylor explains: Finding a balance between exploring new possibilities and reaping the benefits of a particular choice is key to adaptation and survival, and underlies many of the decisions we make in our daily lives. “.

Researchers believe that people with developmental dyslexia have specific strengths related to exploring the unknown that have contributed to the successful adaptation and survival of our species.

Areas of preference for dyslexia

Considering this trade-off between exploration and exploitation, exploratory specialization in people with dyslexia seems to explain why they have difficulty with exploitation-related tasks such as reading and writing. Taylor adds: It could also explain why people with dyslexia appear to be drawn to certain careers that require research-related skills, such as art, architecture, engineering, and entrepreneurship. “.

In fact, a 2009 study of entrepreneurs in the United States found that 35% of them were dyslexic, of which 22% were severely or extremely dyslexic. Additionally, in a 2014 research across several UK universities across four disciplines (engineering, law, medicine and dentistry), scientists reported that self-identified dyslexia accounted for 28% in engineering, compared to 5%.

In addition, the team found that their findings were consistent with evidence from several other areas of research. For example, an exploratory bias in such a large segment of the population suggests that our species must have evolved during a period of great uncertainty and change. This ties in with findings in the field of paleoarchaeology, which show that human evolution has been shaped by dramatic climatic and environmental instability over hundreds of thousands of years.

Finally, the researchers suggest that collaboration between individuals with different abilities may help explain our species’ extraordinary adaptability. Several studies have shown that people with dyslexia have improved skills in various aspects of divergent thinking. The latter includes the ability to generate many solutions or ideas to solve a problem, the flexibility to switch between categories, and the ability to flesh out and develop an idea. This also includes originality, i.e. the ability to come up with new and unusual ideas.

Therefore the authors conclude: Schools, colleges and workplaces are not designed to get the most out of inquiry-based learning. But we urgently need to start fostering this mindset so that humanity can continue to adapt and solve important challenges. “.

Source: Frontiers of Psychology

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