Relationship Between Vocabulary Knowledge,Working Memory And Second Language Reading Comprehension

Recent investigations of reading comprehension have often adopted the component-skills approach to reading,which views reading comprehension as a multivariate skill involving a complex combination and integration of a variety of cognitive,linguistic,and meta-linguistic processes.A better understanding of reading comprehension relies not only on the investigation of how much individual and collective contribution each process makes to reading comprehension,but also on how different processes interact with one another.The present study investigates the relationship between two key reading component variables and academic reading comprehension.Specifically,the study assesses the role of second language vocabulary knowledge,working memory and their interaction in the comprehension of general academic texts in English by a group of adult Chinese learners.There are several reasons to conduct the present study.Firstly,there have been few such comprehensive studies both home and abroad that investigate the individual as well as collective contribution of vocabulary knowledge and working memory to reading comprehension.Secondly,the precise nature of the relationship between vocabulary knowledge and reading comprehension is far from clear.In addition to the discrepancy pertaining to the role of vocabulary depth in second language reading comprehension,there is no research on the effect of the fluency dimension of vocabulary knowledge which is a multidimensional construct in nature.Thirdly,research on the relationship between working memory and second language reading comprehension is still scant.Even among the limited number of studies,most either treat reading comprehension as a global construct without taking into account of the multilevel representational architecture of reading comprehension or only investigate the effect of working memory as a whole on reading comprehension without delineating its separate roles of the processing and storage functions in reading comprehension.Multidimensional studies,therefore,are required to further explore the complex relationship between working memory and reading comprehension.Specifically,the present study investigates the effects of three dimensions of vocabulary knowledge,that is vocabulary breadth(the number of words known),vocabulary depth(the quality of word knowledge)and vocabulary fluency(the speed of lexical access),and working memory on two levels of reading comprehension,namely literal understanding and inferential comprehension.Vocabulary depth involves two aspects:semantic depth(the paradigmatic and syntagmatic relations of words)and morphological depth(morphological knowledge).Sixty seven Grade 2 university students were administered measures of vocabulary size,semantic depth,morphological depth,working memory and reading comprehension.Results showed that all three dimensions of vocabulary knowledge were significantly correlated with reading comprehension.Among the three dimensions of vocabulary knowledge,vocabulary breadth and semantic depth made direct contributions while morphological depth and vocabulary fluency made indirect contributions via either vocabulary breadth or semantic depth,to reading comprehension.Vocabulary breadth was found to be the strongest predictor among the four vocabulary knowledge measures.Working memory capacity and its processing component were found to be significantly correlated with both reading comprehension as a global construct and the level of inferential comprehension,but not with literal understanding.The results also indicated a negative interaction between vocabulary knowledge and working memory in their effects on reading comprehension.Those readers with a lower level of vocabulary knowledge(vocabulary breadth and morphological depth)depended more on working memory capacity in reading comprehension whereas those readers with a higher level of vocabulary knowledge relied more on their vocabulary knowledge.The present study has both theoretical and pedagogical implications.Theoretically,the present study reveals the multidimensional nature of L2 vocabulary knowledge in second language reading comprehension,clarifies the distinctive roles of working memory capacity and its components in different levels of reading comprehension,and also enhances understanding of the interaction between linguistic and cognitive components of second language reading comprehension.Pedagogically,the findings of the present study suggest that reading teaching practitioners should be aware of the three dimensions of vocabulary breadth,vocabulary depth and vocabulary fluency,and their distinctive roles in reading comprehension.