Implicit Learning is Intact in Adult Developmental Dyslexic Readers: Evidence from the Serial Reaction Time Task and Artificial Grammar Learning

Abstract

Previous research yielded equivocal results concerning implicit learning abilities of developmental dyslexic readers. These studies employed a sequence learning task that requires a motor response to each stimulus. However, implicit learning has been often studied using non-motor tasks. Thus, we investigated implicit learning capabilities of adult developmental dyslexic readers in two standard implicit learning paradigms differing in the involvement of the motor system, namely the serial response time task (SRTT) and artificial grammar learning (AGL).Twelve adult developmental dyslexic and twelve age- and sex- matched normal readers were tested. In the serial response time task (SRTT), participants are exposed to a structured display. Learning is measured by comparing response time (RT) to the structured sequence with RT to a random display. In the artificial grammar learning task (AGL), letter strings following a markovian finite state grammar are presented. In a subsequent test phase subjects have to judge new letter strings according to their grammaticality. Learning of the stimulus regularities was found in both tasks and for both groups of subjects. Furthermore, participants were unaware of the underlying stimulus construction principles. Dyslexic readers were unimpaired in SRTT as well as artificial grammar learning relative to normal readers. These findings show that implicit learning is intact in dyslexia. Intact implicit learning capabilities should be taken into account when designing training programs for developmental dyslexic readers.

Do children with developmental dyslexia have impairments in implicit learning?

“…In a typical application of the paradigm (serially presented stimuli), adults with developmental dyslexia showed an equivalent performance to that of non-dyslexic participants leading the authors to propose intact implicit learning (Russeler et al, 2006). Interestingly, in an application of the paradigm that utilized both serial and embedded stimuli (Pothos & Kirk, 2004), dyslexic participants performed well on both tasks whereas non-dyslexics performed equally well as dyslexics on the embedded stimuli but lower on the serially presented stimuli.…”

“…There are only three studies (Pavlidou, Williams, & Kelly, 2009;Pothos & Kirk, 2004;Russeler, Gerth, & Munte, 2006) that have used the AGL paradigm in populations with developmental dyslexia. In a typical application of the paradigm (serially presented stimuli), adults with developmental dyslexia showed an equivalent performance to that of non-dyslexic participants leading the authors to propose intact implicit learning (Russeler et al, 2006).…”

“…In this way, the role of explicit (i.e. working memory influences) and implicit learning can be attributed independently (Russeler et al, 2006). We can investigate more profoundly the share of more sophisticated implicit learning abilities in the aetiology of developmental dyslexia when explicit learning abilities are more carefully controlled.…”

Processing multiple non-adjacent dependencies: evidence from sequence learning

“…[31][32][33]; for an overview, see [34]), brain stimulation [35,36] and special populations such as individuals with Parkinson's disease [37,38], autism spectrum disorders [39], agrammatic aphasia [40] and dyslexia (e.g. [41,42]; for a review, see [43]). These studies have pointed to a general involvement of frontal-striatalcerebellar circuits [44,45] that are also involved in the acquisition of grammatical regularities [45].…”

Individual behavior in learning of an artificial grammar

“…AGL experiments have been performed to investigate syntactic pattern detection in infants (Marcus, Vijayan, Bandi Rao, & Vishton 1999;Saffran, 1996;Saffran, Johnson, Aslin, & Newport 1999), monkeys (Fitch & Hauser, 2004;Hauser, Newport, & Aslin, 2001;Saffran et al, 2008), starlings (Gentner, Fenn, Margoliash, & Nusbaum 2006), and pigeons (Herbranson & Shimp, 2003). AGL has also been used to explore syntactic cognition in patient populations, such as people with aphasia (Caplan, Baker, & Dehaut 1985;Hoen et al, 2003), Parkinson's disease (Smith, Siegert, McDowall, & Newport 2001), and dyslexia (Rüsseler, Gerth, & Münte 2006), in order to determine the integrity of sequential pattern detection abilities. It has further been used to map the neural systems responsible for certain syntactic processes, such as monitoring transition probabilities (Petersson, Forkstam, & Ingvar 2004;Uddén et al, 2008) or hierarchical embedding (Bahlmann, Schubotz, & Friederici 2008).…”