Working Memory and Implicit/Explicit Instruction

While still contentious, there is a lot of evidence that explicit language instruction may be more beneficial than implicit, indirect instruction. This has been supported by general education studies, meta-analyses, and cognitive psychological studies. One factor mediating the success of both explicit and implicit learning may be working memory (WM). Research has shown that WM plays a crucial role in learning. That is, it is the central mechanism for comprehension, attention, and moving information to long-term memory. In fact, it is considered to be one of the most important cognitive individual differences when it comes to language learning. However, WM is part of a much more complex system that includes processing visual and aural information as well as paying attention to various stimuli in our environment. Little research exists that looks at other cognitive capacities, including attention, and how it is related to implicit and explicit learning. It is important to ask if mode of instruction is influenced by any of these cognitive abilities. Indrarathne and Kormos* (2017) looked at WM’s role in learning in both implicit and explicit learning conditions. They found that not only does WM play a major role in the learning of a target grammar structure, but that it may play a large role in learning of productive skills through explicit instruction.

Key Concepts of the Article

  • Explicit learning: “the conscious process of gaining knowledge” (p. 3)
  • Implicit learning: “the process by which knowledge…is acquired independently of conscious attempts to do so” (Reber, 1989, p. 219)
  • Working memory: “the part of short-term memory that is concerned with immediate conscious perceptual and linguistic processing.”
  • The phonological loop and phonological short-term memory (PSTM) – “responsible for processing information related to speech” (p. 3)
  • The Central Executive (CE): “acts as the general attentional controller” and has “three main operations of task switching, inhibition control, and updating” (p. 3)
    • Task Switching:  “the flexibility with which individuals make transitions between tasks” (p. 2)
    • Inhibition: “the mind’s ability to tune out stimuli that are irrelevant to the task/process at hand” (Wikipedia)
    • Updating: “responsible for the efficient manipulation and retrieval of information” (p. 2)
    • Attention Shifting: – “an individual’s capacity to choose what they pay attention to and what they ignore” (Wikipedia)


Previous research shows that higher WM capacity is associated with better reading skills in a second or foreign language. In addition, those with higher WM capacities seem to better at learning grammatical structures. This may be because their WM allows them to better decode written texts and pay more attention to grammatical features.

However, there are some contradictory findings in previous research:

  • Most research indicates WM plays a key role in explicit learning
  • Tagerelli et al (2015) show that WM does not influence implicit learning in explicit conditions
  • Soto and Silvanto (2014) show that WM may play a role in implicit learning
  • Other research on grammar in particular shows WM influences both, one, or none.

One issue here is that these contradictory findings are based on artificial languages, not based on a real language of which learners have prior knowledge and experience. Another issue is that they mostly focus on storage and ignore the other related cognitive functions of the CE.

The Study

The study consisted of 1001 Sri Lankan university students (B1 / low B2) evenly divided into five groups participated in this laboratory-based research. The goal of the experiment was to determine 1) how WM affects learning gains and 2) how does WM relate to attention paid to target items. In the study, causative had (e.g. “My dad had his car fixed”) was the target structure, as it was considered one which the learners had no been exposed to (identified during a pre-test) and the meaning could be derived from context. The groups read three texts at or below level based on the following conditions

Instruction Type Name Explanation Size
Control This group did not receive any experimental treatment and only completed pre- and post- tests, not cognitive tests nor any text reading 20
Explicit enhanced + instructions + explanation This group read textually enhanced (bold target text), instructions to pay attention to bold phrases, and a brief metalinguistic explanation 20
Explicit enhanced + instructions This group received enhanced text and instructions to pay attention 20
Implicit Enhanced This group received enhanced text 20
Implicit Unenhanced This group received the text with no special enhancements  20

A number of tests were used for the experimental groups. A pre-test that consisted of sentence reconstruction (SR) and listening-based grammar judgement (GJ( tests was administered first. During the next three sessions, while participants read, eye-tracking software was used to measure attention paid to target forms. A post-test similar to the pre-test was given after the third session. Three days later, several WM tests were given: a forward Digit-Span test to measure phonological loop storage capacity; Keep Track tasks for measuring updating; Plus-Minus tasks for attention shifting; and an internet-based Stroop task for inhibition.

  1. Due to technological limitations and data collection issues, only 45 participants were included in the eye-tracking data.


  1. There is a strong relationship between WM and learning a previously unknown grammatical structure
  2. Task switching may help in explicit learning conditions
  3. WM played an important role regardless of production (SR) or receptive (GJ)
  4. WM played a role in all experimental conditions – explicit and implicit
  5. Learners with high WM and attentional resources have an advantage regardless of instruction type or whether being tested for productive or receptive skills
  6. Eye-tracking showed that participants paid more attention when explicitly told to do so
  7. Eye-tracking showed that implicit learning conditions did not produce a lot of attention to target grammar

Overall, they found that:

language learners with better WM abilities improve their receptive knowledge more successfully than those with lower levels of storage capacity and updating, and inhibition functions. These findings have direct relevance for language teaching pedagogy as they indicate that this latter group of L2 learners might require extensive exposure to target syntactic (p. 16-17)


I first learned about this research on Twitter. It was publicized by Cambridge University Press Linguistics. The content of the research itself was fascinating from a knowledge-point of view; however, I wondered to what extent this information had any practical bearing on classroom teaching. I asked this question on Twitter and Judit Kormos, one of the authors, replied.. Here were her responses:

Practically speaking, we cannot know every student’s working memory capacity, and, as teachers, we wouldn’t want to label students based on this information, nor would we want this information to be the yardstick by which we judge or treat our students. I asked Dr. Kormos about testing students and differentiating instruction. Her answer spells out clearly some practical advice:

In some contexts…this type of differentiation might not be possible. Therefore, teachers should also consider instructional methods that promote learning for everyone, regardless of their cognitive abilities.  Our study shows that explicit instruction on novel grammatical constructions is more successful than implicit instruction. (emphasis added)


Indrarathne, B., & Kormos, J. (2017). The role of working memory in processing L2 input: Insights from eye-tracking. Bilingualism: Language and Cognition, 1-20.

Reber, A. S. (1989). Implicit learning and tacit knowledge. Journal of Experimental Psychology: General, 118, 219–235.

Soto, D., & Silvanto, J. (2014). Reappraising the relationship between working memory and conscious awareness. Trends in Cognitive Sciences, 18, 520–525.

Tagarelli, K.M., Borges Mota, M., & Rebuschat, P. (2015). Working memory, learning conditions and the acquisition of L2 syntax. In Z. Wen, M. Borges & A. McNeill (Eds.). Working memory in second language acquisition and processing (pp. 224–247). Bristol, England: Multilingual Matters.

*Kormos: A great amount of thanks goes to Dr. Kormos who graciously checked my summary and gave useful feedback! Thank you.

Featured Photo by axonite (Pixabay)

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Anthony Schmidt
English language Instructor at University of Tennessee, Knoxville
Anthony Schmidt is editor of ELT Research Bites. He also has his own blog at Offline, he is a full-time English language instructor in a university IEP program. He is interested in all aspects of applied linguistics, in particular English for Academic Purposes.

2 thoughts on “Working Memory and Implicit/Explicit Instruction”

  1. hi
    although it seems the focus of study was not looking at effects of explicit/implicit instruction i wonder what the authors thoughts are about the extent they feel that the sentence reconstuction and the listening based grammar judgement tests measured any effects of the implicit instruction conditions?

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