The last three decades have seen a significant advancement in describing and understanding task-based language performance and development. So far, however, relatively little research has examined the cognitive processes in which learners engage during task-based work. In this talk, I will argue that, to facilitate theory-construction as well as pedagogical practices, it is crucial that researchers dedicate more attention to task-generated cognitive processes. Taking the case of writing tasks, I will highlight methodological innovations in the field, and demonstrate how adopting more novel data collection technologies (e.g., keystroke-logging, eye-tracking) and combining these with traditional techniques (e.g., verbal protocols) can generate new and more valid information about task-generated cognitive processes. I will also discuss challenges in triangulating and interpreting results obtained from various data sources. In doing so, I will draw on my own and colleagues' recent work on L2 writing processes and behaviours.