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In:Theoretical Issues in Second Language Research: Challenges and new directions
Edited by Junya Fukuta, John Matthews and Shigenori Wakabayashi
[Studies in Bilingualism 69] 2026
► pp. 125–150

Chapter 6
Psychological approaches to the ‘Dual-System Model’ in SLA

A critical overview

 | Kansai University
 | Gakushuin University
This content is being prepared for publication; it may be subject to changes.
Abstract
This paper critically examines the application of dual-system models in Second Language Acquisition (SLA) by drawing parallels with the dual-process framework from cognitive psychology. While the implicit/explicit knowledge distinction has played a key role in SLA theory and practice, recent critiques of dual-system models in psychology — such as logical inconsistencies, oversimplification, and the switch problem — emphasize the need for a deeper reevaluation of SLA’s theoretical underpinnings. By distinguishing between instrumental and substantial views, this study argues that if the goal is to investigate the cognitive mechanisms underlying conscious and unconscious knowledge, the focus should shift from a functional categorization of knowledge (implicit/explicit) to the underlying mechanisms themselves. This approach highlights the limitations of existing models, such as Skill-Acquisition Theory (SAT) in SLA, and advocates for integrating personal and subpersonal levels of explanation to address long-standing questions in SLA. The paper concludes that a more flexible and context-sensitive integration of dual perspectives is essential for advancing theoretical development and practical applications in SLA research.
Article outline
  • 1.Introduction
  • 2.Dual-system models in SLA
  • 3.Criticism in the field of psychology
  • 4.Augusto’s (2024) instrumental/substantial view
  • 5.Examining dual-system models in SLA: Issues and implications
    • 5.1Applying the alignment problem to SLA
    • 5.2Applying the instrumental/substantial framework to SLA
    • 5.3The interface issue
    • 5.4Skill Acquisition Theory: Limitations of the instrumental approach
    • 5.5The switch issue
    • 5.6Formative vs. reflective models
  • 6.Conclusion
  • Author queries
  • References
References (53)
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