The role of depth of processing in ISLA: A research synthesis and meta-analysis

Abstract

Increased interest in depth of processing (DoP) within instructed second language acquisition (ISLA) research highlights its influence on L2 learning outcomes, especially in vocabulary retention, grammatical accuracy, and overall proficiency. Despite its theoretical significance, inconsistencies in DoP’s conceptualization and operationalization have resulted in mixed findings regarding its impact on language development. This study presents a research synthesis and quantitative meta-analysis of ISLA studies on DoP, examining the operational definitions of DoP and the variations in its operationalizations across studies. The analysis examines how DoP affects L2 learning outcomes and how differences in its definition and operationalization shape these outcomes. The study also identifies key limitations in DoP research, including inconsistencies across conceptual frameworks and operationalizations, and a lack of a unified approach. Finally, it discusses the methodological and pedagogical implications of DoP and proposes future research directions to refine its operationalization and explore its sustained effects on L2 development.