Developmental dyslexia-associated cognitive differences from the perspective of cognitive search

In a recent study published in Limits in Psychologyresearchers assessed the features of developmental dyslexia (DD).

Study: Developmental Dyslexia: Disorder or Specialization in Exploration?  Image Credit: Lightspring/Shutterstock
Study: Developmental Dyslexia: Disorder or Specialization in Exploration? Image Credit: Lightspring/Shutterstock

Background

DD is defined as a disorder in children who fail to learn the language skills of writing, reading, and spelling that are consistent with their intellectual abilities, despite attending conventional classroom classes. Cognitive differences related to DD were initially discovered due to lexical difficulties. While later research emphasized the neurophysical and cognitive processes in individuals experiencing DD, it is imperative to understand the non-lexical impact of DD.

Perspective of searching in dyslexia-associated cognition

In the present study, researchers assessed cognitive differences related to DD with regard to various aspects of cognitive search.

The team studied existing information related to individuals with DD, which spanned several cognitive modalities and domains. The evidence was examined for cognitive variations related to cognitive search, taking into account the trade-off between exploration and exploitation. The team considered the different aspects associated with an external query, such as selectively attending data in the external environment, followed by an internal query, including searching for data in/out of memory to look for solutions that specifically for the problems and subsequent neurophysical characterization.

Remote Search

The team explored information using visual and auditory modalities to understand how individuals with DD experience the interaction observed during this search.

Visual Search

Visual information search is the analysis of visual data to identify visuospatial features. There are indications that persons with DD display certain visuospatial talents. A review of complex and dynamic spatial processing in individuals with and without DD showed that individuals with DD performed as well or worse than non-DD individuals on various visuospatial tasks. Several studies also suggested that DD individuals possessed an enhanced ability in both accurate and rapid holistic inspection as the visuospatial information is scanned at a global level rather than a local level.

In addition, individuals diagnosed with DD appear to be faster in 3D mental manipulation and rotation compared to individuals without DD. This suggested that individuals with DD have a unique pathway for processing visual data and use different functional networks for visual processing. Studies also suggested that such a unique processing system could be beneficial in other tasks that require a person to use a different perspective or see patterns in complex shapes.

Studies have also shown that individuals with DD may experience deficits in focal attention but better resolution of peripheral vision. In addition, individuals with DD have a better understanding of low spatial frequency components, while individuals without DD are better at recognizing details in the center of their visual field. Overall, studies indicated that individuals with DD have better explorative or global visual search skills and weaker exploitative or local visual search skills.

Auditory search

One study examined the difference in hearing acuity in children with and without DD. The task requires the children to perceive a series of stimulus words emanating from a particular location, initially without interference and then with interferences such as ‘cocktail party’ speech mask and white noise. The individuals with DD showed markedly worse results than the non-DD individuals, possibly due to the higher number of speech mask intrusions. This indicated that children with DD were unable to filter peripheral speech, further suggesting that individuals diagnosed with DD have broader spatial attention compared to non-DD individuals.

Internal cognitive search

Several studies also examined different areas of memory and their relationship to cognitive search.

procedural memory

Procedural memory is defined as a long-term memory system associated with implicit learning and the use of knowledge inaccessible to consciousness. Studies showed that individuals diagnosed with DD are less efficient than individuals without DD in procedural thinking. This suggested that DD individuals could potentially explore new and potentially better strategies as this unique way of information processing allows for exploratory searching.

Varied Memory

Evidence also showed that individuals with DD exhibit enhanced divergent thinking skills in several respects. Studies showed that individuals with DD outperform non-DD individuals with regard to divergent thinking. However, when verbal, nonverbal and figurative tests of creativity were used, compared to non-DD children, children experiencing DD performed equally in figurative creativity, worse on verbal creativity and significantly better in nonverbal creativity. In addition, studies showed that children with DD performed remarkably better on tasks that required correlating unusual combinations of ideas that supported new and original solutions.

Conclusion

The research results showed that the cognitive search paradigm provided an efficient framework for generating and developing hypotheses explaining the evolution of cognitive differences in DD. The researchers believe that the combination of the cognitive search with other lines of evidence suggests the evolutionary feature of DD’s cognitive features.

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