Document Type : Research Paper


University of Tehran


This synthesis reviews the methodological issues in empirical studies investigating the effect of working memory capacity (WMC) on relative clause ambiguity resolution where results have failed to be consistent cross-linguistically and even intra-linguistically. This discrepancy might have occurred due to ‘methodological inconsistencies’ in the design (Liu & Brown, 2015), administration, and scoring of WMC measures. This study aimed to investigate the aggregative and developmental status of the methodological practices of WMC measures and describe how transparently such practices have been reported. Based on a comprehensive search, 39 experiments were retrieved from 25 studies, culminating in a collection of studies with a time span of 22 years from 1999 to 2021, and coded for 46 features. Results revealed that although over the past 22 years, the field has witnessed significant improvements in the employment of WMC tests, there are still a lot of variations and inconsistencies calling for attempts to raise methodological awareness among researchers to afford more attention to quality and transparency in reporting WMC tests. The article concludes with a call for reform in standardizing WMC tests and a number of other recommendations for future primary and secondary research.


Main Subjects

The asterisked references are included in the methodological synthesis. 
Abdelghany, H., & Fodor, J. D. (1999, September). Low attachment of relative clauses in Arabic. Poster presented at AMLaP (Architectures and Mechanisms of Language Processing) (Vol. 99, pp. 23-25). Edinburgh, UK.
Arabmofrad, A., & Marefat, H. (2008). Relative clause attachment ambiguity resolution in Persian. Iranian Journal of Applied Linguistics, 11(1), 29-49.
Ariji, K., Omaki, A., & Tatsuta, N. (2003). Working memory restricts the use of semantic  information in ambiguity resolution. In P. Slezak (Ed.), Proceedings of the 4th International Conference on Cognitive Science. Sydney, Australia:  University of New South Wales, pp. 19-25.
Ary, D., Jacobs, L. C., Irvine, C. K. S., & Walker, D. (2019). Introduction to research in education (10th ed.). Cengage Learning.
*Başer, Z. (2018). Syntactic priming of relative clause attachment in monolingual Turkish speakers and Turkish learners of English. Unpublished doctoral dissertation. Middle East Technical University, Turkey.
Baumert, A., Buchholz, N., Zinkernagel, A., Clarke, P., MacLeod, C., Osinsky, R., & Schmitt, M. (2020). Causal underpinnings of working memory and Stroop interference control: testing the effects of anodal and cathodal tDCS over the left DLPFC. Cognitive, Affective, & Behavioral Neuroscience, 20(1), 34-48.
Bigby, M. (2009). The hierarchy of evidence. In H. Williams, M. Bigby, T. Diepgen, A. Herxheimer, L. Naldi & B. Rzany (Eds.) Evidence-based dermatology (pp. 34-37). John Wiley & Sons.
Boegle, R., Gerb, J., Kierig, E., Becker-Bense, S., Ertl-Wagner, B., Dieterich, M., & Kirsch, V. (2021). Intravenous delayed gadolinium-enhanced MR imaging of the endolymphatic space: a methodological comparative study. Frontiers in Neurology, 12, 360.
Bolibaugh, C., & Marsden, E. (2021). Reproducibility and research integrity in applied linguistics. MetaArXiv.
Brown, H. D. (2014). Principles of language learning and teaching (6th ed.). Longman.
Brysbaert, M., & Mitchell, D. C. (1996). Modifier attachment in sentence parsing: Evidence from Dutch. The Quarterly Journal of Experimental Psychology Section A, 49(3), 664-695.
Byrnes, H. (2013). Notes from the editor. The Modern Language Journal, 97(4), 825–827.
Carreiras, M. (1992). Estrategias de analisis sintactico en el procesamiento de frases: cierre temprano versus cierre ultimo [Strategies for syntactic analysis in sentence processing: early closure vs. late closure]. Cognitiva 4, 3–27.
Carreiras, M., & Clifton, C. (1999). Another word on parsing relative clauses: Eyetracking evidence from Spanish and English. Memory & Cognition, 27(5), 826-833.
*Cheng, Y., Rothman, J., & Cunnings, I. (2021). Parsing preferences and individual differences in nonnative sentence processing: Evidence from eye movements. Applied Psycholinguistics, 42(1), 129-151.
Conway, A. R., Kane, M. J., Bunting, M. F., Hambrick, D. Z., Wilhelm, O., & Engle, R. W. (2005). Working memory span tasks: A methodological review and user’s guide. Psychonomic Bulletin & Review, 12(5), 769-786.
Cooper, H., Hedges, L. V., & Valentine, J. C. (2019). Research synthesis as a scientific process. In H. Cooper, L. V. Hedges, & J. C. Valentine, (Eds.), The handbook of research synthesis and meta-analysis (pp. 3-18). Russell Sage Foundation.
Crowther, D., Kim, S., Lee, J., Lim, J., & Loewen, S. (2021). Methodological synthesis of cluster analysis in second language research. Language Learning, 71(1), 99-130.
Cuetos, F., & Mitchell, D. C. (1988). Cross-linguistic differences in parsing: Restrictions on the use of the Late Closure strategy in Spanish. Cognition, 30(1), 73-105.
*Dai, Y. (2015). Working memory in L2 sentence processing: The case with relative clause attachment. In Z. Wen, M. B. Mota, & A. McNeill (Eds.) Working memory in second language acquisition and processing (pp. 105-124). Multilingual Matters.
De Vincenzi, M., & Job, R. (1993). Some observations on the universality of the late-closure strategy. Journal of Psycholinguistic Research, 22(2), 189-206.
Derrick, D. J. (2016). Instrument reporting practices in second language research. TESOL Quarterly, 50(1), 132-153.
Dussias, P. E., & Sagarra, N. (2007). The effect of exposure on syntactic parsing in Spanish–English bilinguals. Bilingualism: Language and Cognition, 10(1), 101-116.
Ehrlich, K., Fernandez, E. M., Fodor, J. D., Stenshoel, E., & Vinereanu, M. (1999). Low attachment of relative clauses new data from Swedish, Norwegian, and Romanian. Poster presented at the 12th Annual CUNY Conference on Human Sentence Processing, (pp. 18-20). New York, NY.
Elliott, M. N., Haviland, A. M., Kanouse, D. E., Hambarsoomian, K., & Hays, R. D. (2009). Adjusting for subgroup differences in extreme response tendency in ratings of health care: impact on disparity estimates. Health Services Research, 44(2p1), 542-561.
Farsani, M. A., & Babaii, E. (2020). Applied linguistics research in three decades: a methodological synthesis of graduate theses in an EFL context. Quality & Quantity, 54(4), 1257-1283.
Farsani, M. A., Jamali, H. R., Beikmohammadi, M., Ghorbani, B. D., & Soleimani, L. (2021). Methodological orientations, academic citations, and scientific collaboration in applied linguistics: What do research synthesis and bibliometrics indicate? System, 100, 102547.
Fedorova, O., & Yanovich, I. (2005). Early preferences in RC-attachment in Russian: The effect of Working Memory differences. In J. Lavine, S. Franks, M. Tasseva-Kurktchieva, & H. Filip (Eds.), Proceedings of FASL 14. Ann Arbor, MI: Michigan Slavic Publications, 113–128.
Felser, C., Marinis, T., & Clahsen, H. (2003). Children’s processing of ambiguous sentences: A study of relative clause attachment. Language Acquisition, 11(3), 127–163.
Fernández, E. M. (2003). Bilingual sentence processing: Relative clause attachment in English and Spanish (Vol. 29). Amsterdam: John Benjamins Publishing.
Fernández, E. M., & Sekerina, I. A. (2015). The Interplay of visual and prosodic information in the attachment preferences of semantically shallow relative clauses. In L. Frazier & E. Gibson (Eds.), Explicit and Implicit Prosody in Sentence Processing (pp. 241-261). Springer.
Frazier, L. (1979). On comprehending sentences: Syntactic parsing strategies. Unpublished doctoral dissertation. University of Connecticut, Connecticut, USA.
Frenck-Mestre, C., & Pynte, J. (1997). Syntactic ambiguity resolution while reading in second and native languages. The Quarterly Journal of Experimental Psychology A: Human Experimental Psychology, 50A(1), 119–148.
Hemforth, B., Konieczny, L. & Scheepers C. (2000) Modifier attachment: Relative clauses and coordinations. In B. Hemforth, & L. Konieczny (Eds.), German sentence processing. Studies in theoretical psycholinguistics, Vol. 24, (pp. 161-186). Springer, Dordrecht.
*Hocking, I. (2003). Resources and parsing. Unpublished doctoral dissertation. The University of Exeter.
*Hopp, H. (2014). Working memory effects in the L2 processing of ambiguous relative clauses. Language Acquisition, 21(3), 250-278.
Hou, Z., & Aryadoust, V. (2021). A review of the methodological quality of quantitative mobile-assisted language learning research. System, 100, 102568.
*James, A. N., Fraundorf, S. H., Lee, E. K., & Watson, D. G. (2018). Individual differences in syntactic processing: Is there evidence for reader-text interactions? Journal of Memory and Language, 102, 155-181.
*Jun, S. A., & Bishop, J. (2015). Prominence in relative clause attachment: Evidence from prosodic priming. In L Frazier, E Gibson (Eds.), Explicit and Implicit Prosody in Sentence Processing (pp. 217-240). Springer.
Kamide, Y., & Mitchell, D. C. (1997). Relative clause attachment: Nondeterminism in Japanese parsing. Journal of Psycholinguistic Research, 26(2), 247-254.
*Kaya, M. (2012). Working memory and relative clause attachment preferences in Turkish: An eye-tracking study. Studia Uralo-Altaica, 49, 265-278.  
*Kim, J. (2009). Working memory effects on L2 relative clause processing. 담화· 인지언어학회  학술대회  발표논문집, 59-67. 
*Kim, J. H., & Christianson, K. (2013). Sentence complexity and working memory effects in ambiguity resolution. Journal of psycholinguistic research, 42(5), 393-411.
*Kim, J. H., & Christianson, K. (2017). Working memory effects on L1 and L2 processing of ambiguous relative clauses by Korean L2 learners of English. Second Language Research, 33(3), 365-388.
Leeser, M., & Sunderman, G. (2016). Methodological issues of working memory tasks for L2 processing research. In G. Granena, D. O. Jackson, & Y. Yilmaz (Eds.), Cognitive individual differences in second language processing and acquisition (pp. 89-104). John Benjamins.
Li, S., Ellis, R., & Zhu, Y. (2019). The associations between cognitive ability and L2 development under five different instructional conditions. Applied Psycholinguistics, 40(3), 693-722.
Li, S., & Wang, H. (2018). Traditional literature review and research synthesis. In A. Phakiti, P. De Costa, L. Plonsky, & S. Starfield (Eds.), The Palgrave handbook of applied linguistics research methodology (pp. 123-144). Palgrave Macmillan.
Linck, J. A., Osthus, P., Koeth, J. T., & Bunting, M. F. (2014). Working memory and second language comprehension and production: A meta-analysis. Psychonomic Bulletin & Review, 21, 861–883.
Liu, Q., & Brown, D. (2015). Methodological synthesis of research on the effectiveness of corrective feedback in L2 writing. Journal of Second Language Writing, 30, 66-81.
Loewen, S., & Plonsky, L. (2015). An A–Z of applied linguistics research methods. Macmillan International Higher Education.
Lustig, C., May, C. P., & Hasher, L. (2001). Working memory span and the role of proactive interference. Journal of Experimental Psychology: General, 130(2), 199-207.
MacDonald, M. C., & Christiansen, M. H. (2002). Reassessing working memory: Comments on Just and Carpenter (1992) and Waters and Caplan (1996). Psychological Review, 109, 35–54.
Makel, M., & Plucker, J. (2014). Facts are more important than novelty: Replication in the education sciences. Educational Researcher, 43(6), 304-316.
*Marefat, H., & Farzizadeh, B. (2018). Relative clause ambiguity resolution in L1 and L2: Are processing strategies transferred?. Iranian Journal of Applied Linguistics (IJAL), 21(1), 125-161.
*Marefat, H., Samadi, E., & Yaseri, M. (2015). Semantic priming effect on relative clause attachment ambiguity resolution in L2. Applied Research on English Language, 4(2), 78-95.
Marsden, E. (2020). Methodological transparency and its consequences for the quality and scope of research. In J. McKinley & H. Rose (Eds.), The Routledge handbook of research methods in applied linguistics (pp. 15-28). Routledge.
Marsden, E., Mackey A., & Plonsky, L. (2016). The IRIS Repository: Advancing research practice and methodology. In A. Mackey & E. Marsden (Eds.), Advancing methodology and practice: The IRIS Repository of Instruments for Research into Second Languages (pp. 1-21). Routledge.
Marsden, E., Morgan-Short, K., Thompson, S., & Abugaber, D. (2018). Replication in second language research: Narrative and systematic reviews, and recommendations for the field. Language Learning, 68(2), 321–391.
Marsden, E., Thompson, S., & Plonsky, L. (2017). Open science in second language acquisition research: The IRIS repository of research materials and data. In SHS Web of Conferences (Vol. 38, p. 00013). EDP Sciences.
Marsden, E., Thompson, S., & Plonsky, L. (2018). A methodological synthesis of self-paced reading in second language research. Applied Psycholinguistics, 39(5), 861-904.
McClean, S., Bray, I., Bray, I., de Viggiani, N., Bird, E., & Pilkington, P. (2019). Research methods for public health. Sage.
*Mendelsohn, A., & Pearlmutter, N. J. (1999). Individual differences in relative clause attachment ambiguities. Poster presented at the 12th Annual CUNY Conference on Human Sentence Processing, City University of New York.
Messick, S. (1989). Meaning and values in test validation: The science and ethics of assessment. Educational researcher, 18(2), 5-11.
Miyamoto, E. T. (1998). Relative clause processing in Brazilian Portuguese and Japanese. Unpublished doctoral dissertation. Massachusetts Institute of Technology, Massachusetts, USA.
Najjari, R., & Mohammadi, M. (2017). The Development of Reading and Operation Span Tasks in Persian as Measures of Working Memory Capacity for Iranian EFL Learners. Journal of Teaching Language Skills, 36(2), 129-162.
Nakanishi, T. (2015). A meta‐analysis of extensive reading research. TESOL Quarterly, 49(1), 6-37.
Norris, J. M., & Ortega, L. (2000). Effectiveness of L2 instruction: A research synthesis and quantitative meta‐analysis. Language Learning, 50(3), 417-528.
Norris, J. M., & Ortega, L. (2006). The value and practice of research synthesis for language learning and teaching. In J. M. Norris, & L. Ortega (Eds.), Synthesizing research on language learning and teaching (pp. 3-50). John Benjamins Publishing.
*Omaki, A. (2005). Working memory and relative clause attachment in first and second language processing. Unpublished master’s thesis. University of Hawaii.
Ortega, L. (2003). Syntactic complexity measures and their relationship to L2 proficiency: A research synthesis of college‐level L2 writing. Applied Linguistics, 24(4), 492-518.
Oswald, F. L., & Plonsky, L. (2010). Meta-analysis in second language research: Choices and challenges. Annual Review of Applied Linguistics, 30, 85-110.
Papadopoulou, D., & Clahsen, H. (2003). The role of lexical and contextual information in parsing ambiguous sentences in Greek. Department of Language and Linguistics, University of Essex.
*Payne, B. R., Grison, S., Gao, X., Christianson, K., Morrow, D. G., & Stine-Morrow, E. A. (2014). Aging and individual differences in binding during sentence understanding: Evidence from temporary and global syntactic attachment ambiguities. Cognition, 130(2), 157-173.
Pigott, T. D. (2012). Advances in meta-analysis. Springer.
Plonsky, L. (2014). Study quality in quantitative L2 research (1990–2010): A methodological synthesis and call for reform. The Modern Language Journal, 98(1), 450-470.
Plonsky, L. (2017). Quantitative research methods. In S. Loewen & M. Sato (Eds.), The Routledge handbook of instructed second language research (pp. 505–521). Routledge.  
Plonsky, L., & Gass, S. (2011). Quantitative Research Methods, Study Quality, and Outcomes: The Case of Interaction Research. Language Learning, 61(2), 325–366.
Plonsky, L., & Ghanbar, H. (2018). Multiple regression in L2 research: A methodological synthesis and guide to interpreting R2 values. The Modern Language Journal, 102(4), 713-731.
Plonsky, L., & Gonulal, T. (2015). Methodological synthesis in quantitative L2 research: A review of reviews and a case study of exploratory factor analysis. Language Learning, 65(S1), 9-36.
Plonsky, L., & Oswald, F. (2015). Meta-analyzing second language research. In L. Plonsky (Ed.), Advancing quantitative methods in second language research (pp. 106–128). Routledge.
Plonsky, L., Marsden, E., Crowther, D., Gass, S. M., & Spinner, P. (2020). A methodological synthesis and meta-analysis of judgment tasks in second language research. Second Language Research, 36(4), 583-621.
Rosenthal, R. (1979). The file drawer problem and tolerance for null results. Psychological Bulletin, 86(3), 638–641.
Shakki, F., Naeini, J., Mazandarani, O., & Derakhshan, A. (2020). Instructed second language English pragmatics in the Iranian context. Journal of Teaching Language Skills, 39(1), 201-252.
Samadi, E. (2014). Relative Clause Attachment Ambiguity Resolution in L2:  The Role of Semantics. Unpublished master’s thesis. The University of Tehran.
Samavarchi, L. & Rezai, M. J.  (2014). Online Processing of English Wh-Dependencies by Iranian EFL Learners. Journal of Teaching Language Skills, 32(4), 63-83.
Shariat, M. (2019). Relative clause ambiguity resolution: A case for individual differences among second language learners. Unpublished master’s thesis. The University of Tehran.
Sheykholmoluki, H. (2014). Memory span and proficiency: Do they affect attachment  preference of Persian l2 learners of English? Unpublished master’s thesis. The University of Tehran.
Shin, J. (2020). A meta-analysis of the relationship between working memory and second language reading comprehension: Does task type matter? Applied Psycholinguistics, 41, 873-900.
Sok, S., Kang, E. Y., & Han, Z. (2019). Thirty-five years of ISLA on form-focused instruction: A methodological synthesis. Language Teaching Research, 23(4), 403-427.
Soleimani, E. (2018). Relative clause ambiguity resolution by second language learners of English:  Impact of WMC and discourse cues. Unpublished master’s thesis. University of Tehran.
Swets, B., Desmet, T., Hambrick, D. Z., & Ferreira, F. (2007). The role of working memory in syntactic ambiguity resolution: a psychometric approach. Journal of Experimental Psychology: General, 136(1), 64-81.
Traxler, M. J. (2007). Working memory contributions to relative clause attachment processing: A hierarchical linear modeling analysis. Memory & Cognition, 35(5), 1107-1121.
Traxler, M. J. (2009). A hierarchical linear modeling analysis of working memory and implicit prosody in the resolution of adjunct attachment ambiguity. Journal of Psycholinguistic Research, 38(5), 491-509.
Whitney, P., & Budd, D. (1999). A separate language-interpretation resource: Premature fractionation? Behavioral and Brain Sciences, 22(1), 113-113.
Yeh, L. H. (2011). The role of cross-language activation in syntactic ambiguity. Unpublished doctoral dissertation. The University of Texas at El Paso.
Zhang, M., & Plonsky, L. (2020). Collaborative writing in face-to-face settings: A substantive and methodological review. Journal of Second Language Writing, 49, 100753.
Ziegler, N. (2016). Synchronous computer-mediated communication and interaction. Studies in Second Language Acquisition, 38(3), 553-586.