The interaction between timing of explicit grammar explanation and individual differences in second language acquisition

Despite numerous positive findings of explicit instruction, this topic continues to engage scholars worldwide. One issue that may be crucial for the effectiveness of explicit instruction is the interaction between cognitive individual differences (language aptitude and working memory) and types of instruction. In this experiment, 128 learners of Spanish were randomly assigned to four experimental treatments and completed comprehension-based practice for interpreting object-verb and ser/estar sentences in Spanish. Results revealed that the various combinations of rules and practice posed differential task demands on the learners and consequently drew on language aptitude and working memory to a different extent. We argue that not only are rules and practice both necessary, but that their suitable integration ameliorates task demands, reducing the burden on the learner, and accordingly mitigates the role of participants’ individual differences, thus making a substantial difference for the learning of second language grammar.