Neural circuitry associated with two different approaches to novel word learning

Abstract

Skilled reading depends upon successfully integrating orthographic, phonological, and semantic information; however, the process of becoming a skilled reader with efficient neural circuitry is not fully understood. Short-term learning paradigms can provide insight into learning mechanisms by revealing differential responses to training approaches. To date, neuroimaging studies have primarily focused on effects of teaching novel words either in isolation or in context, without directly comparing the two. The current study compared the behavioral and neurobiological effects of learning novel pseudowords (i.e., pronouncing and attaching meaning) trained either in isolation or in sentential context. Behavioral results showed generally comparable pseudoword learning for both conditions, but sentential context-trained pseudowords were spoken and comprehended slightly more quickly. Neurobiologically, fMRI activity for reading trained pseudowords was similar to real words; however, an interaction between training approach and reading proficiency was observed. Specifically, highly skilled readers showed similar levels of activity regardless of training approach. However, less skilled readers differentiated between training conditions, showing comparable activity to highly skilled readers only for isolation-trained pseudowords. Overall, behavioral and neurobiological findings suggest that training approach may affect rate of learning and neural circuitry, and that less skilled readers may need explicit training to develop optimal neural pathways.

Explicit versus Implicit Instruction: Which Is Preferable for Learning an Artificial Morphological Rule in Children?

“…The results suggest that in 8-year-old learners, explicit explanation can trigger the development of explicit knowledge that may afford an effective initial base for the subsequent proceduralization of task performance, including the fluent generalization of the AMR to new items. This finding is in line with the notion that for children, explicit instruction may contribute to the learning of linguistic tasks [13,14,21]. While implicit knowledge is specific and therefore is limited in its generalizability [49,78], explicit knowledge can not only be easily generalized [79] but also pave the way for subsequent proceduralization and fluent skilled performance [60,61,62,63,64,65,66,67,68,69,70,71,72].…”

“…Although substantial evidence has accumulated in support of explicit instruction [2,3,6,11,13,14,15,16], this approach is fraught with controversy [17,18,19,20]. Moreover, most experiments addressing the issue of implicit-explicit instruction have been performed on adults [3,6,7,18,21,22]. There is a very strong case for the notion that children, who are considered very efficient language learners, acquire grammar without explicit instruction, through implicit learning, based on exposure and incidental experience [23,24,25,26,27].…”

“…Although children constitute the primary target population for improved language intervention programs, most experiments have been performed on adults [3,6,7,10,18,21,22]. Given that the explicit mechanisms are still immature in childhood [1,65,66,67], an important question is whether children are able to take advantage of explicit explanation when learning grammatical rules.…”

Individual differences in decoding skill, print exposure, and cortical structure in young adults

“…Becoming literate entails changes to the brain’s cortical structure, both in grey and white matter (Carreiras et al, 2009; Castro-Caldas et al, 1999; Petersson, Silva, Castro-Caldas, Ingvar, & Reis, 2007). There is substantial evidence for individual behavioral differences in reading comprehension and its components (for reviews see Long, Johns, & Morris, 2006; van den Broek, Mouw, & Kraal, 2015; Wagner, Piasta, & Torgesen, 2006), and that these differences often correlate with differences in functional activity in task-relevant brain regions (e.g., Clements-Stephens et al, 2012; Meyler et al, 2008; Shankweiler et al, 2008; Welcome & Joanisse, 2012). However, although it might be assumed that cortical structure and function may be similarly related to such behavioral differences, there is relatively little structural evidence available to support this hypothesis (for review see Richardson & Price, 2009).…”

Individual differences in decoding skill, print exposure, and cortical structure in young adults

“…There is substantial evidence for individual behavioural differences in reading comprehension and its components (for reviews see Long, Johns, & Morris, 2006;van den Broek, Mouw, & Kraal, 2015;Wagner, Piasta, & Torgesen, 2006), and that these differences often correlate with differences in functional activity in task-relevant brain regions (e.g. Clements-Stephens et al, 2012;Meyler, Keller, Cherkassky, Gabrieli, & Just, 2008;Shankweiler et al, 2008;Welcome & Joanisse, 2012). However, although it might be assumed that cortical structure may be similarly related to such behavioural differences, there is relatively little evidence available to support this hypothesis (for review see Richardson & Price, 2009).…”