To offer an expansive background about L2 learning, teaching and assessment from a CI perspective and guide the readers to connect theory, research and practice progressively, Chapters 1 through 3 (Part 1) laid the theoretical foundation. As the first chapter in Part 2, this chapter sheds light on cognition-based L2A theories. Basically, it examines how learners utilize their cognitive abilities and capacity when they attend to and process input. Here, the focus is on the nature and role of cognition in processing input because input is composed of numerous linguistic, sociocultural, pragmatic and stylistic properties (Chapter 2). Specifically, the subject matter included in this chapter includes cognitive aspects of comprehension, acquisition and development of L2 input as well as the nature of input (implicit versus explicit) and processes of attention (focal and peripheral), noticing, awareness, control, memory, retention, processability capacity, knowledge (declarative, procedural, explicit and implicit), association and storage.

Cognition and L2 Learning Processes

In terms of the role of cognition in comprehending and learning L2 input, some cognitivists have viewed certain forms of input to be more difficult than others due to the higher levels of cognitive processing demands they impose on working memory capacity (Sweller, 1994). As far as cognitive demands are concerned, cognitive theory suggests that three types of cognitive processes take place when learners encounter new information: essential processing, incidental processing and representational holding. In terms of input, essential processing refers to cognitive processes a learner depends on for comprehension purposes. Incidental processing comprises supplementary information of secondary importance; information that plays a facilitating role in the comprehension of input. Representational holding, on the other hand, involves the temporary holding of some information to lessen possible overload on working memory capacity while other information is being processed (Mayer & Moreno, 2003).