The present study sought to observe, through online treatments, whether explicit information assists acquisition in a way that has not been measured in previous processing instruction (PI) studies. Two experiments examined learners' behavior while they processed Spanish sentences with object-verb-subject (OVS) word order and Spanish subjunctive under two treatments: with explicit information (the PI group) and without explicit information (the structured input [SI] group). Participants in both groups worked individually with a computer and processed a series of 30 SI items. They received feedback right after each response, and both accuracy and response time were recorded. It was expected that learners in the PI group would start to process both of the linguistic targets sooner in the sequence of input items and would submit their responses faster than learners in the SI group, because explicit information in the PI treatment would help learners notice the target items early in the series. The results showed no difference between the SI group and the PI group when processing OVS sentences, but the PI group processed subjunctive forms sooner and faster than the SI group. The results suggest that the benefits of explicit information might depend on the nature of the task and the processing problem.

Effects of pedagogical interventions with visual input enhancement on grammar learning have been investigated by a number of researchers during the past decade and a half. The present review delineates this research domain via a systematic synthesis of 16 primary studies (comprising 20 unique study samples) retrieved through an exhaustive literature search. The overall magnitude of visual input enhancement was addressed by calculating and aggregating effect size d values. The results indicate that second language readers provided with enhancement-embedded texts barely outperformed those who were exposed to unenhanced texts with the same target forms flooded in them (d = 0.22). A theoretical tension between form and meaning was indicated by a small but negative effect size value for learners' meaning processing (d = −0.26). The importance of improving methodological practices in this research domain, including the reporting of statistical and treatment-related information and the counteracting of a possible publication bias, was also revealed by the synthetic analyses and is further discussed.

This study investigates whether advanced second language (L2) learners of a nonnull subject language (Dutch) are influenced by their null subject first language (L1) (Turkish) in their offline and online resolution of subject pronouns in L2 discourse. To tease apart potential L1 effects from possible general L2 processing effects, we also tested a group of German L2 learners of Dutch who were predicted to perform like the native Dutch speakers. The two L2 groups differed in their offline interpretations of subject pronouns. The Turkish L2 learners exhibited a L1 influence, because approximately half the time they interpreted Dutch subject pronouns as they would overt pronouns in Turkish, whereas the German L2 learners performed like the Dutch controls, interpreting pronouns as coreferential with the current discourse topic. This L1 effect was not in evidence in eye-tracking data, however. Instead, the L2 learners patterned together, showing an online processing disadvantage when two potential antecedents for the pronoun were grammatically available in the discourse. This processing disadvantage was in evidence irrespective of the properties of the learners' L1 or their final interpretation of the pronoun. Therefore, the results of this study indicate both an effect of the L1 on the L2 in offline resolution and a general L2 processing effect in online subject pronoun resolution.

Despite the frequency with which verbal reports are used in SLA to gather data on learners' cognitive processes (e.g., Bowles, 2003, 2004; Mackey, Gass, & McDonough, 2000; Rosa & Leow, 2004a, 2004b), only two studies (Bowles & Leow, 2005; Leow & Morgan-Short, 2004) have investigated verbal reports' reactivity (i.e., whether they alter cognitive processes) during second language (L2) reading. This is the first study to investigate the reactivity of verbal reports on a L2 problem-solving task. First-semester learners of Spanish were assigned to one of six experimental conditions, which differed in terms of the type of verbalization (i.e., metalinguistic, nonmetalinguistic, or silent) and the type of feedback (i.e., implicit vs. explicit). Results show that metalinguistic verbalization significantly increased time on task and also hindered participants' ability to produce exemplars of the target structure seen during the experimental task. However, neither type of verbalization significantly affected participants' ability to produce novel exemplars of the target structure, and there was no interaction between verbalization and feedback.