Neoliterate adult dyslexia and literacy policies : a neurocognitive research review of a curious unexplored phenomenon

There are about 750 million adult illiterates who in principle could learn fluent reading. However, adult literacy programs have performed poorly. Various social and operational reasons may be responsible. This paper explores the role of some neurocognitive reasons in adult performance. Automatic readers of a script detect letters and words effortlessly and involuntarily. Adults learning new scripts find it hard to attain this performance. Whether illiterate or educated, adults learning a new script detect letters slowly, may make mistakes, understand little, soon abandon the task, and may also forget what they learned. When neoliterates glance at a text, they often see a jumble of letters and may process only a few of their features. They must activate reading consciously and sound out each letter. The difficulties are perceptual, and interviews suggest that perceptual distortions may continue for decades. This phenomenon called “neoliterate adult dyslexia” (NAD) has escaped attention, possibly because few educated adults need to learn new scripts, and because the adult literacy failures are often attributed to social reasons. The phenomenon also may have been missed because researchers of perceptual learning use simpler stimuli. Automaticity in reading musical notation and air traffic control may reflect similar age-related learning difficulties. In the brain, the problem may originate at the early stages of the parietal cortex at the dorsal reading path, which constricts short-term visual memory. The visual areas V1 and perhaps V4 may also be involved. Deficits affect the ventral path that provides parallel processing and direct ‘print-to-meaning’ reading. Some neuronal groups may have a sensitive period that affects the capacity to collect frequency data and to integrate the appropriate features of letters and words. Then adults do not learn to perceive letter shapes and words as easily as most children do. A lack of data and research makes it difficult to design effective interventions. The adults’ difficulties are not linguistic. Dysfluent readers simply cannot decipher the symbols in sufficient time to get to the meaning of texts, or they do so after considerable conscious visual effort. Therefore language competence seems to have little relationship to the visuospatial tasks described in this document. Language knowledge does help predict likely words when judgements must be made on the basis of just a few letter features, but the relative ease of linguistic identification may lead to reading errors. The readers’ symptoms resonate with descriptions of severe and unremitting developmental dyslexia. Certain perceptual deficits may arise during adolescence and become more severe in adulthood. Some adults may become better readers than others. But learning a script at increasingly later ages seems related to worse outcomes, though no data exist to map this trajectory. To explore this curious phenomenon, this review brings together a range of insights from of neurocognitive research, notably studies on (a) perceptual learning, including studies on feature integration and face recognition; (b) neurocognitive studies aimed at dyslexic children, (c) studies of adults suffering from brain damage that causes alexia, and (d) performance of adult literacy programs. Implications and potential remedies are also presented. The author posits the hypothesis that perhaps all people become dyslexics for new alphabets at about age 19, and that ability to read new alphabets fluently decreases with age. Neoliterate adult dyslexia (NAD) may partly account for the difficulties of adult literacy programs. Thus it seems to impact about 750 million adult illiterates. For this reason, the paper calls for urgent research into this phenomenon.