In recent years, an increasing number of SLA researchers have been motivated by the WM–L1 association (as reviewed in Chapter 4) and become increasingly interested in exploring the relationships between WM and SLA (e.g. see Juffs & Harrington, 2011; Sagarra, 2013; Wen, 2012a, 2015; Williams, 2012). Due to the fundamental differences between L1 acquisition (L1A) and SLA, researchers have hypothesized that WM may play a greater if not an equal role in SLA than in L1A. In this chapter, I aim to provide an updated review of these theoretical perspectives on WM and SLA, and synthesize the empirical studies on the effects of WM on various areas of L2 learning and processing.

In the first section, I summarize the major theoretical perspectives adopted by cognitive-oriented SLA researchers on the role of WM in L2 learning and processing. I mainly discuss the role that WM plays in Skehan's classical 'information processing' perspective and in Nick Ellis's recent 'connectionist' account of SLA. The section following this theoretical discussion tabulates and synthesizes the current strands of empirical research on the effects of WM on various areas of L2 learning and processing. In the third section, I further reveal that these WM–SLA studies have not only produced positive findings on the relationship between the components/functions of WM and the L2 domains and skills, but also revealed the inherent limitations and pitfalls in the current research designs and methodologies. The last section then summarizes the various WM–L2 associations that have emerged from the current empirical research.

Theoretical Perspectives on WM and SLA

WM in Skehan's 'information processing' perspective on SLA

Embracing the classical information processing approaches, some SLA researchers (e.g. Harrington, McLaughlin, Miyake and Skehan) postulate that L1A is unequivocally dominated by implicit and mostly automatic processing (a typical example being the seemingly effortless language acquisition by children in their mother tongue), while SLA usually takes place much later in life (e.g. among adults) and is generally characterized by explicit and more controlled processing (Harrington, 1992; McLaughlin, 1995).