Working memory (WM) is the limited-capacity cognitive system responsible for temporarily holding and manipulating information during complex tasks such as reasoning, comprehension, and language production. In SLA, individual differences in WM capacity are among the strongest predictors of L2 learning outcomes, particularly for explicit learning and in the early stages of acquisition.
The dominant model in SLA research is Baddeley and Hitch's (1974) framework, updated by Baddeley (2000):
| Component | Function | Relevance to SLA |
|---|---|---|
| Phonological loop | Stores and rehearses verbal/acoustic information | Critical for vocabulary acquisition: holds new word forms during encoding. Predicts L2 vocabulary learning in children and adults |
| Visuospatial sketchpad | Stores visual and spatial information | Less directly relevant to language, though may support reading of logographic scripts |
| Central executive | Attentional control, coordination, inhibition | Manages competing demands during L2 processing, e.g., parsing syntax while tracking meaning. Predicts performance on complex L2 tasks |
| Episodic buffer (added 2000) | Integrates information from multiple sources into coherent episodes | May support integration of phonological form, meaning, and context during L2 learning |
Vocabulary: The phonological loop's capacity to temporarily store unfamiliar sound sequences is a strong predictor of L2 vocabulary acquisition (Baddeley, Gathercole & Papagno, 1998). Learners with greater phonological short-term memory learn new words faster.
Grammar: The central executive's role in managing attention and inhibiting interference predicts success with complex L2 grammar, particularly under explicit learning conditions.
Listening comprehension: Real-time L2 listening requires simultaneous parsing, meaning construction, and retention, all dependent on WM capacity. Lower-proficiency learners, for whom processing is less automatised, face greater WM demands.
Noticing: Schmidt's Noticing Hypothesis requires that learners consciously attend to form, a process that consumes WM resources. Learners with greater WM capacity may notice more, more often.
As L2 knowledge becomes proceduralised and automatised, its processing demands on WM decrease. This frees up WM capacity for higher-level operations (discourse planning, monitoring, pragmatic adjustment). The progression from effortful, WM-intensive processing to fluent, automatic performance is a central trajectory of L2 development.
Common WM measures in SLA research: