It is widely believed that adults cannot learn a foreign language in the same way that children learn a first language. However, recent evidence suggests that adult learners of a foreign language can come to rely on native-like language brain mechanisms. Here, we show that the type of language training crucially impacts this outcome. We used an artificial language paradigm to examine longitudinally whether explicit training (that approximates traditional grammar-focused classroom settings) and implicit training (that approximates immersion settings) differentially affect neural (electrophysiological) and behavioral (performance) measures of syntactic processing. Results showed that performance of explicitly and implicitly trained groups did not differ at either low or high proficiency. In contrast, electrophysiological (ERP) measures revealed striking differences between the groups’ neural activity at both proficiency levels in response to syntactic violations. Implicit training yielded an N400 at low proficiency, whereas at high proficiency, it elicited a pattern typical of native speakers: an anterior negativity followed by a P600 accompanied by a late anterior negativity. Explicit training, by contrast, yielded no significant effects at low proficiency and only an anterior positivity followed by a P600 at high proficiency. Although the P600 is reminiscent of native-like processing, this response pattern as a whole is not. Thus, only implicit training led to an electrophysiological signature typical of native speakers. Overall, the results suggest that adult foreign language learners can come to rely on native-like language brain mechanisms, but that the conditions under which the language is learned may be crucial in attaining this goal.

Despite its critical role for the development of the field, little is known about replication in second language (L2) research. To better understand replication practice, we first provide a narrative review of challenges related to replication, drawing on recent developments in psychology. This discussion frames and motivates a systematic review, building on syntheses of replication in psychology, education, and L2 research. We coded 67 self-labeled L2 replication studies found across 26 journals for 136 characteristics. We estimated a mean rate of 1 published replication study for every 400 articles, with a mean of 6.64 years between initial and replication studies and a mean of 117 citations of the initial study before a replication was published. Replication studies had an annual mean of 7.3 citations, much higher than averages in linguistics and education. Overlap in authorship between initial and replication studies and the availability of the initial materials both increased the likelihood of a replication supporting the initial findings. Our sample contained no direct (exact) replication attempts, and changes made to initial studies were numerous and wide ranging, which likely obscured, if not undermined, the interpretability of replication studies. To improve the amount and quality of L2 replication research, we propose 16 recommendations relating to rationale, nomenclature, design, infrastructure, and incentivization for collaboration and publication.

This study employed an artificial language learning paradigm together with a combined behavioral/event-related potential (ERP) approach to examine the neurocognition of the processing of gender agreement, an aspect of inflectional morphology that is problematic in adult second language (L2) learning. Subjects learned to speak and comprehend an artificial language under either explicit (classroomlike) or implicit (immersionlike) training conditions. In each group, both noun-article and noun-adjective gender agreement processing were examined behaviorally and with ERPs at both low and higher levels of proficiency. Results showed that the two groups learned the language to similar levels of proficiency but showed somewhat different ERP patterns. At low proficiency, both types of agreement violations (adjective, article) yielded N400s, but only for the group with implicit training. Additionally, noun-adjective agreement elicited a late N400 in the explicit group at low proficiency. At higher levels of proficiency, nounadjective agreement violations elicited N400s for both the explicit and implicit groups, whereas noun-article agreement violations elicited P600s for both groups. The results suggest that interactions among linguistic structure, proficiency level, and type of training need to be considered when examining the development of aspects of inflectional morphology in L2 acquisition. Keywordssecond language acquisition; event-related potentials; language processing; explicit; implicit; agreement Aspects of inflectional morphology, including grammatical gender agreement in noun phrases (NPs), seem to be particularly difficult for late second language (L2) learners to acquire (Montrul, 2004; Montrul, Foote, Perpiñán, Thornhill, & Vidal, 2008;White, 2003).Correspondence concerning this article should be addressed to Kara Morgan-Short, Departments of Spanish, French, Italian and Portuguese and Psychology, 1706 UH MC 315, University of Illinois at Chicago, Chicago, IL 60607. Internet: karams@uic.edu; Michael T. Ullman, Department of Neuroscience, Georgetown University, Washington, DC 20057. Internet: michael@georgetown.edu. NIH Public Access Author ManuscriptLang Learn. Author manuscript; available in PMC 2011 February 24.Published in final edited form as:Lang Learn. 2010 March ; 60(1): 154-193. doi:10.1111/j.1467-9922.2009.00554.x. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptEven for learners at advanced levels of proficiency, errors in gender agreement appear to persist (Dewaele & Veronique, 2001;Franceschina, 2005). Although this issue has been addressed from multiple perspectives (Arteaga, Herschensohn, & Gess, 2003;Bartning, 2000;Benati, 2005;De Jong, 2005;Dewaele & Veronique, 2001;Franceschina, 2005;Gass & Alvarez Torres, 2005;Hawkins & Chan, 1997;Keating, 2009;Montrul, 2004;Montrul et al., 2008;White, Valenzuela, Kozlowska-Macgregor, & Leung, 2004), neurocognitive research has only begun to consider the development, representation, and processing of L2 grammatical gender ...

Although it is widely known that high-pass filters can reduce the amplitude of slow ERP components, these filters can also introduce artifactual peaks that lead to incorrect conclusions. To demonstrate this and provide evidence about optimal filter settings, we recorded ERPs in a typical language processing paradigm involving syntactic and semantic violations. Unfiltered results showed standard N400 and P600 effects in the semantic and syntactic violation conditions, respectively. However, high-pass filters with cutoffs at 0.3 Hz and above produced artifactual effects of opposite polarity before the true effect. That is, excessive high-pass filtering introduced a significant N400 effect preceding the P600 in the syntactic condition, and a significant P2 effect preceding the N400 in the semantic condition. Thus, inappropriate use of high-pass filters can lead to false conclusions about which components are influenced by a given manipulation. The present results also lead to practical recommendations for high-pass filter settings that maximize statistical power while minimizing filtering artifacts.

This study examined how individual differences in cognitive abilities account for variance in the attainment level of adult second language (L2) syntactic development. Participants completed assessments of declarative and procedural learning abilities. They subsequently learned an artificial L2 under implicit training conditions and received extended comprehension and production practice using the L2. Syntactic development was assessed at both early and late stages of acquisition. Results indicated positive relationships between declarative learning ability and syntactic development at early stages of acquisition and between procedural learning ability and development at later stages of acquisition. Individual differences in these memory abilities accounted for a large amount of variance at both stages of development. The findings are consistent with theoretical perspectives of L2 that posit different roles for these memory systems at different stages of development, and suggest that declarative and procedural memory learning abilities may predict L2 grammatical development, at least for implicitly trained learners.