3 A METHODOLOGICAL REVIEW OF THE RESEARCH ON TASK COMPLEXITY IN SECOND LANGUAGE ORAL PRODUCTION Hao Lin and Shaofeng Li Introduction This research synthesis is a methodological review of research on task complex- ity in second language (L2) learning. Task complexity refers to the cognitive demands a learning task imposes on the learner. According to Robinson’s (2011) Cognition Hypothesis, factors affecting task complexity fall into two groups: resource-directing and resource-dispersing, with the former referring to the con- ceptual demands of tasks and the latter to the procedural aspects of tasks. In- creasing task complexity along resource-directing dimensions directs learners’ cognitive resources to complex concepts, which results in more complex and accurate linguistic production and more learning opportunities. According to Robinson, there are multiple ways to increase the resource-directing dimension of task complexity, such as adding or increasing reasoning demands, asking learners to describe events that happened in the past and at another location instead of events that are ongoing at the current location, increasing the num- ber of elements of the task, etc. These factors have been examined extensively in empirical research. However, there has been a high degree of methodologi- cal heterogeneity, which may be partly responsible for the disparate results and affect the generalizability of the results. Thus, a methodological synthesis is necessary that summarizes the methodological features, identifies issues, and proposes solutions, and this study is undertaken to achieve these goals. This syn- thesis focuses on the research methods of oral studies examining the resource- directing dimensions of task complexity. DOI: 10.4324/9781003500216-4