Atypical Reinforcement Learning in Developmental Dyslexia

Objectives: According to the Procedural Deficit Hypothesis, abnormalities in corticostriatal pathways could account for the language-related deficits observed in developmental dyslexia. The same neural network has also been implicated in the ability to learn contingencies based on trial and error (i.e., reinforcement learning [RL]). On this basis, the present study tested the assumption that dyslexic individuals would be impaired in RL compared with neurotypicals in two different tasks. Methods: In a probabilistic selection task, participants were required to learn reinforcement contingencies based on probabilistic feedback. In an implicit transitive inference task, participants were also required to base their decisions on reinforcement histories, but feedback was deterministic and stimulus pairs were partially overlapping, such that participants were required to learn hierarchical relations. Results: Across tasks, results revealed that although the ability to learn from positive/negative feedback did not differ between the two groups, the learning of reinforcement contingencies was poorer in the dyslexia group compared with the neurotypicals group. Furthermore, in novel test pairs where previously learned information was presented in new combinations, dyslexic individuals performed similarly to neurotypicals. Conclusions: Taken together, these results suggest that learning of reinforcement contingencies occurs less robustly in individuals with developmental dyslexia. Inferences for the neuro-cognitive mechanisms of developmental dyslexia are discussed.

Sustained attention, not procedural learning, is a predictor of reading, language and arithmetic skills in children

This is an original manuscript of an article published by Taylor & Francis in Scientific Studies of Reading (SSR) on 14th April, 2020, available online: http://www.tandfonline.com/[Article DOI: http://dx.doi.org/10.1080/10888438.2020.1750618].The procedural deficit hypothesis claims that impaired procedural learning is a causal risk factor for developmental dyslexia and developmental language disorder. We investigated the relationships between measures of basic cognitive processes (declarative learning, procedural learning and attention) and measures of attainment (reading, grammar and arithmetic) in a large sample of 7- and 8-year-old children. A latent variable path model showed that verbal declarative memory skills predicted attainment but were not significantly related to attention. Procedural learning was only weakly related to measures of attainment and attention assessed during the procedural learning task accounted entirely for its relationship with measures of attainment. Our results challenge the procedural deficit hypothesis of reading and language disorders, but suggest that attentional skills (rather than procedural learning ability per se) may be an important predictor of reading, arithmetic and grammatical skills.

Implicit Spoken Words and Motor Sequences Learning Are Impaired in Children with Specific Language Impairment

Objectives: This study aims to compare verbal and motor implicit sequence learning abilities in children with and without specific language impairment (SLI). Methods: Forty-eight children (24 control and 24 SLI) were administered the Serial Search Task (SST), which enables the simultaneous assessment of implicit spoken words and visuomotor sequences learning. Results: Results showed that control children implicitly learned both the spoken words as well as the motor sequences. In contrast, children with SLI showed deficits in both types of learning. Moreover, correlational analyses revealed that SST performance was linked with grammatical abilities in control children but with lexical abilities in children with SLI. Conclusions: Overall, this pattern of results supports the procedural deficit hypothesis and suggests that domain general implicit sequence learning is impaired in SLI. (JINS, 2016, 22, 1–10)

Procedural Learning in Specific Language Impairment: Effects of Sequence Complexity

According to the procedural deficit hypothesis (PDH), abnormal development in the procedural memory system could account for the language deficits observed in specific language impairment (SLI). Recent studies have supported this hypothesis by using a serial reaction time (SRT) task, during which a slower learning rate is observed in children with SLI compared to controls. Recently, we obtained contrasting results, demonstrating that children with SLI were able to learn a sequence as quickly and as accurately as controls. These discrepancies could be related to differences in the statistical structure of the SRT sequence between these studies. The aim of this study was to further assess, in a group of 21 children with SLI, the PDH with second-order conditional sequences, which are more difficult to learn than those used in previous studies. Our results show that children with SLI had impaired procedural memory, as evidenced by both longer reaction times and no sign of sequence-specific learning in comparison with typically developing controls. These results are consistent with the PDH proposed by Ullman and Pierpont (2005) and suggest that procedural sequence-learning in SLI children depends on the complexity of the to-be-learned sequence. (JINS, 2013, 19, 1–8)