On the importance of anchoring and the consequences of its impairment in dyslexia

Abstract

One of the main impediments of individuals with reading difficulties and individuals with language difficulties is poor working memory. Typically measured using verbal stimuli, working memory deficits have often been considered as one aspect of the phonological difficulty putatively underlying dyslexia. Over the years it has been shown that a broad range of auditory discrimination abilities are also mildly impaired. Here we present evidence that a domain general, rather than a phonology specific, deficits in the ability to implicitly use contextual information, which we term anchoring, can account for both types of deficits. We propose that anchoring ability, which reflects a basic biological mechanism for replacing effortful mechanisms of explicit working memory with automatic mechanisms of implicit memory, and consequently boost performance in both perceptual and cognitive tasks, is a crucial factor in our ability to be expert users of oral and written language.

Dysfunction of Rapid Neural Adaptation in Dyslexia

“…First, individuals with dyslexia may have an impairment “anchoring” to consistent stimulus statistics in order to enhance perceptual thresholds (Ahissar et al, 2006; Banai and Ahissar, 2010), a behavioral effect reflected in rapid neural adaptation (Fritz et al, 2003; Garrido et al, 2009). Second, individuals with dyslexia are also frequently observed to have impairments recognizing both auditory and visual stimuli in the presence of noise (Sperling et al, 2005, 2006; Ziegler et al, 2009).…”

Anchoring in 4- to 6-year-old children relates to predictors of reading

“…In particular, the role of domain-general factors in the establishment of those domain-specific reading precursors is not clear. Based on studies in adolescents and adults, it has been previously suggested that anchoring, a domain-general process that allows individuals to implicitly benefit from contextual information embedded in sequences of stimuli, might be such a factor (Ahissar, 2007;Banai & Ahissar, 2010). By this account, anchoring is a simple case of statistical learning or predictive processing that allows the extraction of the properties of stimulus sequences, resulting in improved performance when a stimulus sequence has a property that enables anchoring.…”

“…The findings presented above led to the formulation of the anchoring deficit hypothesis, namely that impaired anchoring mechanisms play a causal role in the etiology of dyslexia because they force individuals with dyslexia to rely on effortful and explicit operations in circumstances under which the general population uses implicit and automatic anchoring mechanisms (Ahissar, 2007;Banai & Ahissar, 2010). Therefore, whereas the dominant phonological deficit theory attributes both typical and atypical reading development to the ability to consciously process and manipulate the sound structure (phonology) of spoken language (e.g., Ziegler & Goswami, 2006), we have suggested that an implicit, domain-general process that is shared between language and non-language tasks also plays a role in reading acquisition.…”

Developmental dyslexia: The difficulties of interpreting poor performance, and the importance of normal performance

“…A significant group difference was found only with the small set, when listeners could gradually form implicit expectations about the repeated words. Ahissar and colleagues (M. Ahissar, 2007;Banai & Ahissar, 2010) proposed that this aspect of fast learning, "anchoring", is impaired in dyslexia: specifically, the detection of sound regularities within a window of several seconds to minutes-that is, longer than the 2 -3-second window of working memory. They interpreted these findings as indicating that dyslexics' performance is limited neither by the stimulus dimension (e.g., tone frequency) nor by its complexity, but rather by the efficiency of anchoring to recently presented stimuli.…”