required to be processed, the resources or space would be compromised under the competition among the needs to deal with tasks at hand. In the long run, it increases the burden on central executive and slows down the efficiency to complete the immediate task. Due to this, it makes WMC related to cognitive tasks and the efficiency of accomplishing them.
WM is highly related to RC basically because WM helps maintain immediate information in mind. More importantly, WM enables readers to construct meanings from multifaceted resources under conditions of full engagement (Tierney, 1990). In terms of engagement, one important construct of WM is the automatic operation of inhibition, which controls the content or mental representation of WM by preventing irrelevant stimuli from overloading WM capacity (Borella & De Beni, 2008; Engle, 2001; Kramer, Humphrey, Larish, & Logan, 1994; Rosen & Engle, 1998). From this perspective, it is clearly that both RC and operation of WMC tap the same construct, which explains the high correlation between the two shown in numerous studies. Also, Daneman and Carpenter (1980) found that the result from RSTs, individuals’ WMC (working memory capacity), is able to predict participants’ prose comprehension skills in their college participants. They continued to find more details of the ways which WMC seemed to underpin components of WMC, such as the ability to make inference and to extrapolate beyond the given literal information.
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Furthermore, Just and Carpenter (1992) noted that the dual functions of storage and process in WM make humans capable of conducting various linguistic (speech, sound, and visuo-spatial) and conceptual tasks (semantic and episodic information) smoothly and automatically. During the automatic cognitive process, comprehending a text for instance, relevant information from LTM is retrieved and would be combined with the dynamic newly-received information in WM so as to establish a meaningful mental representation as a whole (Alptekin & Ercetin, 2009; Daneman & Carpenter, 1983; Daneman & Merikle, 1996; Walter, 2004). And this automatic cognitive process makes WM relevant to RC performances.
When it comes to L1 or L2 in terms of WM and RC, studies show that L2 RC is more relevant to L2 WM than to L1 WM (Daneman & Hannon, 2007). It is suggested that cognitive resources underlying L1, L2 and even L3 are closely related to each other. L1 WMC is found to be strongly or moderately correlated to L2 WM capacity. The
correlation was both over .70, which suggests a strong relation force (Osaka & Osaka, 1992; Osaka, Osaka & Groner, 1993). Other studies found a moderate correlation between L1 and L2 WM capacity ranging from .39 to .68. That led to the burgeoning studies concerning the relationship between WM and L1/L2 RC for that WM is said to be a good predictor of RC and scant studies investigate the cross-language interplay of WMC and comprehension (Danemen & Carpenter, 1980; Harrington & Sawyer, 1992).
As indicated in several studies, L2 WM capacity is strongly correlated to L2 RC rather than L1 WM capacity to L2 RC (Chun &Payne, 2004; Walter, 2004; Miyake & Friedman, 1998). Hence this paper is aimed at studying English as L2 RC under the influence of L2 WMC.
Measurement for WMC—Reading Span Test (RST)
Individuals’ WMC is usually measured with a dual-task which requires participants to complete both processing and storage tasks. Span tasks for measuring WMC usually
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“include a dual-task paradigm which combines a memory span measure with a concurrent processing task” (Alptekin & Ercetin, 2010, p.206). Dual-tasks are designed to measure the two functions of WMC—to temporarily store and process information at the same time. It comes in a variety of types, such as operating span, counting span, and reading span. The WM theory emphasizes the functional importance of “an immediate-memory system that could briefly stores a limited amount of information in the service of ongoing mental activities” (Conway et al., 2005, p.769). The design of dual-tasks could assess individuals’ ability to store and process information at the same time. In comparison with other span tasks which do not include readings in procedure, a RST, according to research would have better validity and reliability when it comes to the relationship between WMC and RC (Conway, et al., 2005; Friedman & Miyake, 2004).
What is a dual-task precisely? In completing a RST, participants need to complete two tasks simultaneously. According to Conway et al. (2005), the WM system would fail to demonstrate its function fully if it is encountered with one single task of simply storing information or rehearsing factual information. Instead of one single task, dual-tasks or complex tasks have been developed to measure WMC and the efficiency of central
executive inside WMC. Complex tasks demonstrate to-be-remembered stimuli, such as
letters or numbers, and those stimuli are spread between interfering components, such as reading sentences (Daneman& Carpenter, 1980) or problems to solve (Turner & Engle, 1989). Complex tasks are to measure WMC and are more related to high order cognitive tasks, such as making reading inference (McCabe et al., 2010; Unsworthy & Brewer, 2009). Regarding the trade-off between processing and storage as interdependent components operating inside WM, the tasks are assumed to show that “increase in the amount of processing demands leads to a decrease in the number of storage items and vice versa” (Alptekin & Ercetin, 2010, p.206).The literature has emphasized the importance of WM when it comes to its influence
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on RC; however, there is little consensus on the measurements and assessments of WM (Friedman & Miyake, 2004; Juffs, 2004; Waters & Caplan, 1996). Difference WMC tasks have different procedures or tasks (Waters & Caplan, 1996). For instance, a recall-RST requires readers to judge the grammaticality of sentences and write down cues afterwards (Harrington & Sawyer, 1992; Walter, 2004). A cognition-RST requires readers also to judge the grammaticality of sentences but to identify ending words of sentences from a list of provided options.
A recognition-RST measures the participants’ abilities to recognize the ending words from the provided options or “externally presented retrieval cues” (Unsworth & Engle, 2007, p.112). Unsworth and Engle (2007) suggest that performances in recognition-RST are mainly driven by two independent mechanisms: fast-pacing and automatic process of recognition based on familiarity. Likewise, Alptekin and Ercetin (2009) pointed out that the performance of recognition-RSTs could be “partially contingent on a strategically controlled search process of long-term working memory or on the automatic retrieval of information from long-term working memory” (p.635). During the process of completing a recognition-RST, participants can quickly target ending words from externally presented cues, which is called the automatic process of recognizing words. It operates based on participants’ recognition of familiarity or words which they have read from the RST. In the dual-task of grammaticality judgment in recognition-RST participants need to respond to externally presented retrieval cues. The provided list of sentences or the
multiple-choice questions provide participants with the chance to retrieve relevant information from their long-term working memory by recognizing cues automatically.
However, when completing a recall-RST, participants remember the ending words from memory, which resembles free-recall tasks. To complete a recall-RST, the
participants recall their memory of ending words from their internally generated cues.
Short-term working memory is activated in the controlled search process inside long-term
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working memory. Instead of automatically recognizing words, participants internally generate retrieval cues by using relevant cues to the presented ending words with knowledge from their long-term working memory. Altepkin and Ercetin (2009) suggest that there is a qualitative difference between recall-RSTs and recognition-RSTs in terms of their different cognitive constructs. A recall-RST requires the participants’ abilities to inhibit irrelevant information and to focus on relevant information in order to retrieve items using internally generated cues. Thus, free-recall tasks or recall-RSTs would be more demanding than recognition-RSTs and the cognitive demands posed by these two different RST types on individuals should be different. It is expected to see the influence of WM on RC vary when WMC is measured with these two RST types.
Regardless of RST types, researchers proposed that WM span tasks of all kinds all account for similar or the same variance in comprehension (Turner and Engle, 1989).
However, Chun and Payne (2004) found no significant correlation between WMC and RC when using recognition-RSTs in their research. According to Chun and Payne (2004), the cognitive tasks in recognition-RST in which readers recognize correct options of ending words from RST do not correspond to the construct behind RC. To investigate the relationship between WM and RC, studies should consider the factors of different WMC tasks and dimensions of RC (Chun & Payne, 2004). That is, different amounts and types of working memory cognitive resources involved in different cognitive tasks is usually not taken into consideration in studies (Alptekin & Ercetin, 2009). Given the scant consensus concerning which RST is better to measure WM, the investigator was interested to find out whether the influence of WM on RC would vary when WM is measured with a recall-RST and a recognition-RST. To sum up, this paper was aimed to find out the relationship between L2WM of English learners in high school and their abilities to make literal and inferential comprehensions.
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