Learning new languages is a complex cognitive task involving both implicit and explicit processes. Batterink, Oudiette, Reber, and Paller (2014) report that participants with vs. without conscious awareness of a hidden semi-artificial language regularity showed no significant differences in grammar learning, suggesting that implicit/explicit routes may be functionally equivalent. However, their operationalizing of learning via median reaction times might not capture underlying differences in cognitive processes. In a conceptual replication, we compared rule-aware (n=14) and rule-unaware (n=21) participants via drift-diffusion modeling, which can quantify distinct subcomponents of evidence-accumulation processes (Ratcliff & Rouder, 1998). For both groups, grammar learning was manifested in non-decision parameters, suggesting anticipation of motor responses. For rule-aware participants only, learning also affected bias in evidence accumulation during word reading. These results suggest that implicit grammar learning may be manifested through low-level mechanisms whereas explicit grammar learning may involve more direct engagement with encoded target meanings.

Research has examined the role of domain-general cognitive factors in second language (L2) acquisition, with emerging evidence implicating a role for procedural memory, a long- term memory system (e.g., Morgan-Short et al., 2014). Strong conclusions regarding the role of procedural memory are hindered by the lack of knowledge regarding the reliability and validity of procedural memory assessments. In this study, participants completed three assessments of procedural memory that have previously been used to study L2 learning, along with assessments of declarative memory, working memory, and an artificial L2 learning task. Results indicated that the procedural memory assessments generally showed evidence of reliability and discriminant validity, but, somewhat surprisingly, evidence for convergent validity was lacking. Finally, one procedural memory assessment showed predictive validity for the L2 learning task. Implications for future research on the role of procedural memory in L2 acquisition will be considered in light of these results.

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.