Maturational Constraints on the Recruitment of Early Processes for Syntactic Processing

Abstract

An enduring question in the study of second language acquisition concerns the relative contributions of age of acquisition (AOA) and ultimate linguistic proficiency to neural organization for second language processing. Several event-related potential (ERP) and neuroimaging studies of second language learners have found that neural organization for syntactic processing is sensitive to delays in second language acquisition. However, such delays in second language acquisition are typically associated with lower language proficiency, rendering it difficult to assess whether differences in AOA or proficiency lead to these effects. Here we examined the effects of delayed second language acquisition while controlling for proficiency differences by examining participants who differ in AOA but who were matched for proficiency in the same language. We compared the ERP response to auditory English phrase structure violations in a group of late learners of English matched for grammatical proficiency with a group of English native speakers. In the native speaker group violations elicited a bilateral and prolonged anterior negativity, with onset at 100 ms, followed by a posterior positivity (P600). In contrast, in the non-native speaker group violations did not elicit the early anterior negativity, but did elicit a P600 which was more widespread spatially and temporally than that of the native speaker group. These results suggest that neural organization for syntactic processing is sensitive to delays in language acquisition independently of proficiency level. More specifically they suggest that both early and later syntactic processes are sensitive to maturational constraints. These results also suggest that late learners who reach a high level of second language proficiency rely on different neural mechanisms than native speakers of that language.

Individual Differences in Language Acquisition and Processing

“…reading experiments [111,112] (n = 80) that investigated adults' processing of center-embedded subject ('the boy that clauses [43], resolving syntactic ambiguities [1,44], using contextual information for ambiguity resolution [45], and interpreting pronouns [46]. Variability is reliably observed at the neurological as well as the behavioral level [47,48]. More recently, there have been demonstrations of IDs among typically developing adults in ultimate attainment [49].…”

Idiosyncratic Grammars: Syntactic Processing in Second Language Comprehension Uses Subjective Feature Representations

“…For example, in a study by Kotz, Holcomb, and Osterhout (2008), early Spanish L2 speakers of English displayed accuracy rates in grammaticality judgments of only 56% on long sentences containing reduced relative clauses. As in other L2 studies (Pakulak & Neville, 2011;Chen et al, 2007;Ojima et al, 2005;Tokowicz & MacWhinney, 2005;Weber-Fox & Neville, 1996), sentences with correct and incorrect grammaticality judgments were grouped together in the analyses in that study. In our view, collapsing across sentences that are perceived as correct and as incorrect into the same conditions might lead to inconsistent results, in particular when they are compared with those of native speakers (for whom subjective and objective correctness converge).…”

Implicit and Explicit Second Language Training Recruit Common Neural Mechanisms for Syntactic Processing

“…Most previous investigations on the neurobiology of L2 processing have focused on bilinguals who acquired their L2 in school, presumably largely through explicit instruction (e.g., Perani et al, 1996; Perani et al, 1998; Dehaene et al, 1997; Hahne, 2001; Hahne & Friederici, 2001; Tokowicz & MacWhinney, 2005; McLaughlin, Osterhout & Kim, 2004; Rossi, Gugler, Friederici & Hahne, 2006; Ojima, Nakata, & Kakigi, 2005; Pakulak & Neville, 2011). Relatively few studies have included bilinguals who likely acquired their L2 in more implicit environments, having been exposed to their L2 before reaching school age (Wartenburger et al, 2003; Weber-Fox & Neville, 1996; Chee et al, 1999), and of those that have, age of acquisition and learning environment tend to be confounded.…”

“…Thus, very little is known about the neural mechanisms that are recruited as a consequence of implicit L2 exposure, including the degree to which these mechanisms are dissociable from those supporting explicit L2 learning. Although this question is beginning to gain more interest (Morgan-Short et al, 2010; 2012a; 2012b), overall the lack of evidence on this topic stands in contrast to other parameters of L2 learning, such as age of acquisition, proficiency, and L1-L2 similarity, which have been much more thoroughly investigated (e.g., Weber-Fox & Neville, 1996; Perani et al, 1998; Chee et al, 1999; Wartenburger et al, 2003; Rossi et al, 2006; Abutalebi, 2008; Pakulak & Neville, 2011; Sabourin & Stowe, 2008; Tokowicz & MacWhinney, 2005; Foucart & Frenck-Mestre, 2011). This is somewhat surprising, as neurobiological research in this area has the potential not only to yield basic evidence concerning human learning mechanisms, but also to inform L2 teaching practices.…”