DOKTORI DISSZERTÁCIÓ
TASK COMPLEXITY AND SECOND LANGUAGE NARRATIVE PRODUCTION:
EFFECTS OF INDIVIDUAL DIFFERENCES IN WORKING MEMORY, FOREIGN LANGUAGE APTITUDE AND ANXIETY
TREBITS ANNA
2011
Eötvös Loránd Tudományegyetem Pedagógiai és Pszichológiai Kar
DOKTORI DISSZERTÁCIÓ
TREBITS ANNA
TASK COMPLEXITY AND SECOND LANGUAGE NARRATIVE PRODUCTION:
EFFECTS OF INDIVIDUAL DIFFERENCES IN WORKING MEMORY, FOREIGN LANGUAGE APTITUDE AND ANXIETY
NARRATÍV FELADATOKON NYÚJTOTT TELJESÍTMÉNY
ÖSSZEFÜGGÉSEI A MUNKAMEMÓRIÁVAL, A NYELVÉRZÉKKEL ÉS A SZORONGÁSSAL NYELVTANULÓK KÖRÉBEN
ELTE PPK Neveléstudományi Doktori Iskola Iskolavezető: Dr. Bábosik István, DSc., egyetemi tanár
Nyelvpedagógia Doktori Program
Programvezető: Dr. Károly Krisztina, PhD. habil. egyetemi docens Témavezető: Dr. Dolgosné Dr. Kormos Judit, PhD. habil. egyetemi adjunktus
A bíráló bizottság:
Elnök: Dr. Medgyes Péter DSc., egyetemi tanár Opponensek: Dr. Csizér Kata PhD.
Dr. Ottó István PhD.
A bizottság tagjai:
Dr. Racsmány Mihály PhD., egyetemi docens Dr. Csépes Ildikó PhD., egyetemi adjunktus Dr. Tóth Zsuzsanna PhD., egyetemi adjunktus Titkár: Dr. Albert Ágnes PhD., egyetemi tanársegéd
Budapest, 2011. február 16.
ABSTRACT
Individual differences in cognitive abilities and affective traits have been shown to be highly relevant both in theoretical accounts of second language acquisition and in pedagogical decision-making. The study of tasks has received much attention in communicative and task-based language teaching over the past decades.
Everyday communicative routines can be seen as a series of tasks, which may provide learners with opportunities for practicing language, and language tasks can be designed and sequenced in such a way as to direct learners’ attention to linguistic forms and structures.
The aim of this dissertation was to investigate how cognitive task complexity affects L2 narrative production and how certain individual variables differentiate learners’ performance on two types of oral and written tasks. The participants were 44 secondary school students enrolled in an English-Hungarian bilingual educational programme in Hungary. The participants’ working memory capacity and input, processing and output anxiety were assessed in addition to their foreign language aptitude measured by a standardized test.
The participants performed two types of narrative tasks in both speaking and writing.
The results show that task-relevant measures of performance reflect more accurately the individual and combined effects of task type, cognitive task complexity and learner variables on linguistic output. It was also found that the effect of complex working memory capacity on students’ narrative performance was limited to lexical diversity and syntactic complexity. The effect of phonological short-term memory was imminent on subordination complexity and the accuracy of participants’ performance. The findings also indicate a complex interaction between the components of foreign language aptitude and task performance. Deductive ability and grammatical sensitivity seemed to be most strongly related to the accuracy and complexity of production. This study has shown that spoken and written modes of task performance are influenced differently by anxiety experienced at the input, processing and output stages of L2 production.
With regard to the effect of task complexity on participants’ narrative production, the findings of this research suggest that the various stages of language production need to be taken into account when categorizing tasks on the basis of the cognitive load they impose on learners. Current taxonomies and models of cognitive task complexity would need to be complemented if we attempt to contribute to the development of task- and research-based syllabus design.
ACKNOWLEDGEMENTS
First and foremost, I would like to thank my supervisor, Dr. Kormos Judit for her support and encouragement from the start of my PhD studies, and for her thorough comments on earlier drafts of this dissertation. Needless to say, all remaining shortcomings are my own. I am also grateful to my tutors at the PhD programme for their insights and support. My gratitude goes to Dr. Károly Krisztina, Dr. Holló Dorottya and Dr. Csizér Kata who gave me detailed feedback on my research proposal. I am also greatly indebted to Dóra Török and the students who participated in this research project. Finally, a special thank you goes to my family for without their help and patience throughout the writing process, this dissertation could not have been written.
Table of Contents
Abstract………....3
Acknowledgements………..4
Table of Contents………...5
List of Tables………..10
List of Figures……….13
Chapter 1: Introduction………...14
1 Background and rationale………..14
2 Motivation for the present research………...15
3 Research questions……….17
4 Overview of the dissertation………..18
Chapter 2: Theoretical Background……….20
2.1 Tasks in language learning and teaching………20
2.1.1 Fromcommunicative totask-based language teaching………... 20
2.1.2 Defining “task”……….24
2.1.2.1 Task definitions……….24
2.1.2.2 Task types and task-based syllabi………..26
2.1.3 Models of task complexity and task taxonomies………..28
2.1.4 Task complexity and the allocation of attention………...34
2.1.4.1 Attention and task performance………..35
2.1.4.2 Task complexity and L2 production………...39
2.1.5 Measures of task performance………..43
2.1.5.1 Defining complexity, accuracy and fluency………..44
2.1.5.2 General and specific measures of CAF……….47
2.1.5.3 Beyond CAF measures………..48
2.2 Individual differences and L2 learning………...51
2.2.1 Introduction………..51
2.2.2 Working Memory……….52
2.2.2.1 The structure of memory and the Working Memory Model……...53
2.2.2.2 Measures of phonological short-term memory and working memory...57
2.2.2.3 Working memory and L2 learning………..60
2.2.3 Foreign language aptitude………....62
2.2.3.1 Defining foreign language aptitude………...63
2.2.3.2 The Modern Language Aptitude Test (MLAT)……….64
2.2.3.3 Foreign language aptitude in SLA research………..66
2.2.3.4 New directions in aptitude research………..69
2.2.3.4.1 The Cognitive Ability for Novelty in Acquisition of Learning as applied to foreign language test (CANAL-FT)………..69
2.2.3.4.2 The Linguistic Coding Differences Hypothesis (LCDH)……...71
2.2.3.4.3 Working memory as foreign language aptitude………..71
2.2.3.4.4 Language pedagogy and foreign language aptitude………72
2.2.4 Foreign language anxiety……….74
2.2.4.1 The construct of anxiety………74
2.2.4.2 Types of anxiety………76
2.2.4.3 Defining Foreign Language Anxiety (FLA)………..77
2.2.4.4 Effects of FLA on L2 performance………...79
2.2.4.4.1 Cognitive processes and FLA………...79
2.2.4.4.2 The interaction of FLA and other IDs in L2 learning………….83
2.2.4.4.3 FLA and L2 skills………85
2.3 Language production...86
2.3.1 From thoughts to words………86
2.3.2 Speech production………88
2.3.2.1 Theories of L1 speech production………..88
2.3.2.2 Differences between L1 and L2 speech production………...90
2.3.3 Spoken versus written language production……….93
2.3.4 Writing performance and theories of writing………...94
2.3.5 The role of attention and memory in oral and written L2 production…101 Chapter 3: Empirical Background………...105
3.1 Researching task features: interactional perspectives………...105
3.2 Research into the effects of cognitive task complexity on L2 production………108
3.2.1 Task types………...108
3.2.2 Cognitive task complexity variables………..109
3.2.3 Researching the interplay of cognitive task complexity and ID effects on L2 narrative production………...113
3.2.4 Other variables………...115
3.2.5 Modes of performance………116
3.3 The comparability of the findings……….126
Chapter 4: Method………..128
4.1 Design………128
4.2 Participants………128
4.3 Instruments………130
4.3.1 Narrative tasks………130
4.3.2 Non-word span test……….131
4.3.3 Backward digit span………...132
4.3.4 Foreign language aptitude test (HUNLAT)………132
4.3.5 Input, processing and output anxiety scale (IPOAS)………..134
4.4 Procedures……….135
4.5 Analysis……….135
4.5.1 Measures of task performance………....135
4.5.2 Statistical analysis………..139
Chapter 5: Individual Differences in Ability and Affective Variables………...140
5.1 Introduction………...140
5.2 Results………...140
5.2.1 Working memory tests………...140
5.2.2 Foreign language aptitude (HUNLAT) test………143
5.2.3 Input, processing and output anxiety (IPOA) scale………145
5.2.4 Correlations between ID factors...146
5.3 Discussion……….148
5.4 Conclusion………151
Chapter 6: Task Performance Differences Between Task Types and Across
Modes of Performance...152
6.1 Introduction………...152
6.2 Results………...152
6.2.1 Characteristics of narrative tasks in oral and written modes of Performance………152
6.2.2 Task performance on different task types in oral and written modes……...156
6.3 Discussion……….. ..161
6.3.1 Intercorrelation of output measures on narrative tasks……….161
6.3.2 Differences between task types………163
6.3.3 Differences between modes of performance………166
6.3.4 The psycholinguistic characteristics of the task types across modalities…...168
6.4 Conclusion………...170
Chapter 7: Task Performance and Individual Differences in Working Memory, Foreign Language Aptitude and Input, Processing and Output Anxiety……….172
7.1 Introduction………..172
7.2 Results………..173
7.2.1 Correlations of phonological short-term memory and complex working memory capacity and task performance………...173
7.2.2 Correlations of aptitude and task performance……….184
7.2.3 Correlations of input, processing and output anxiety and task performance………...187
7.3 Discussion……….190
7.3.1 The relationship between working memory capacity and narrative task performance………190
7.3.1.1 Phonological short-term memory and oral task performance……..190
7.3.1.2 Phonological short-term memory and written task performance….191 7.3.1.3 Complex working memory and oral task performance………192
7.3.1.4 Complex working memory and written task performance………...194
7.3.2 The relationship between foreign language aptitude and narrative
task performance...196
7.3.2.1 Foreign language aptitude and oral task performance………..196
7.3.2.2 Foreign language aptitude and written task performance………….198
7.3.3 The relationship between input, processing and output anxiety (IPOA) and narrative task performance...199
7.3.3.1 IPOA and oral task performance………..199
7.3.3.2 IPOA and written task performance……….201
7.4 Conclusion……….204
Chapter 8: Conclusions………...207
Chapter 9: Limitations, pedagogical implications and directions for future research………214
References………...217
Appendix A – Cartoon description task………..248
Appendix B – Picture narration task………...249
Appendix C – Non-word span test………..250
Appendix D – Backward digit span test………..251
Appendix E – Sample items from the HUNLAT test……….252
Appendix F – IPOA Scale in Hungarian………...253
List of Tables
Table 1 Task types and task characteristics in different research agendas...27
Table 2 Earlier proposals of task grading criteria...30
Table 3 Contrasting the claims of the Trade-Off and Cognition Hypotheses...41
Table 4 CAF measures used in TBLT studies...46
Table 5 Tasks commonly used to assess phonological short-term and working memory capacity...58
Table 6 Summary of tasks used in the MLAT, the PLAB and the HUNLAT...66
Table 7 Studies on the interaction between anxiety and other ID factors...84
Table 8 Studies on anxiety and reading, listening, and writing...85
Table 9 The stages of writing...96
Table 10 Research into cognitive task complexity...117
Table 11 Studies on the interplay of cognitive task complexity and ID effects on L2 narrative performance...122
Table 12 Summary of the research focus of studies investigating the interplay ID and task complexity variables...124
Table 13 Summary of L2 writing studies...125
Table 14 Summary of results comparing L2 production across modalities – Groups 2 and 3...125
Table 15 Measures of accuracy, complexity and fluency used in the present study...139
Table 16 Descriptive statistics of the non-word span test...141
Table 17 Frequencies of the non-word span test...141
Table 18 Descriptive statistics of the backward digit span test...142
Table 19 Frequencies of the backward digit span test...142
Table 20 Descriptive statistics of the aptitude test (HUNLAT) scores...143
Table 21 Paired samples t-test comparing performance on the four subtests of the HUNLAT...144
Table 22 Intercorrelations of the aptitude test (HUNLAT)...144
Table 23 Descriptive statistics of the input, processing and output anxiety (IPOA) test...145
Table 24 Paired samples t-test comparing participants’ IPOA scores...146
Table 25 Intercorrelations of the IPOA average ratings...146
Table 26 Correlations between working memory capacity (backward digit span test (BW) and non-word test (NW)) and aptitude components (HUNLAT test)...147
Table 27 Correlations between working memory capacity (backward digit span test (BW) and non-word span test (NW)) and input, processing and output anxiety average ratings (IPOA test)...147
Table 28 Correlations between aptitude components (HUNLAT tests) and input, processing and output anxiety (IPOA) test average ratings...148
Table 29 Intercorrelations of linguistic measures of the oral cartoon description task...153
Table 30 Intercorrelations of linguistic measures of the oral picture narration task...154
Table 31 Intercorrelations of linguistic measures of the written cartoon description task...155
Table 32 Intercorrelations of linguistic measures of the written picture narration task...156
Table 33 Descriptive statistics of the linguistic variables...157
Table 34 Paired samples t-test comparing performance on the oral cartoon description and picture narration tasks...158
Table 35 Paired samples t-test comparing performance on the written cartoon description and picture narration tasks...158
Table 36 Paired samples t-test comparing performance on the cartoon description task across modalities...159
Table 37 Paired samples t-test comparing performance on the picture narration task across modalities...159
Table 38 Correlations of the same linguistic measures on the two task types in oral mode...160
Table 39 Correlations of the same linguistic measures on the two task types in written mode...161
Table 40 Correlations of the same linguistic measures on Task 1 and Task 3...161
Table 41 Correlations of the same linguistic measures on Task 2 and Task 4...161 Table 42 Overview of the psycholinguistic characteristics of the tasks with relation to
the major findings of this study...169 Table 43 The comparison of task performance of students with different non-word
(NW) spans on the oral cartoon description task...175 Table 44 The comparison of task performance of students with different non-word
(NW) spans on the oral picture narration task...176 Table 45 The comparison of task performance of students with different non-word
(NW) spans on the written cartoon description task...177 Table 46 The comparison of task performance of students with different non-word
(NW) spans on the written picture narration task...178 Table 47 The comparison of task performance of students with different backward
digit spans on the oral cartoon description task...180 Table 48 The comparison of task performance of students with different backward
digit spans on the oral picture narration task...181 Table 49 The comparison of task performance of students with different backward
digit spans on the written cartoon description task...182 Table 50 The comparison of task performance of students with different backward
digit spans on the written picture narration task...183 Table 51 The correlations of linguistic variables with language aptitude scores
in the oral cartoon description task...185 Table 52 The correlations of linguistic variables with language aptitude test scores
in the oral picture narration task...185 Table 53 The correlations of linguistic variables with language aptitude test scores
in the written cartoon description task...186 Table 54 The correlations of linguistic variables with language aptitude test scores
in the written picture narration task...186 Table 55 The correlations of linguistic variables with IPOA test scores in the
oral cartoon description task...188 Table 56 The correlations of linguistic variables with IPOA test scores in the
oral picture narration task...188 Table 57 The correlations of linguistic variables with IPOA test scores in the
written cartoon description task...189
Table 58 The correlations of linguistic variables with IPOA test scores in the
written picture narration task...190
List of Figures
Figure 1 Skehan’s model of task difficulty...31Figure 2 Robinson’s Triadic Componential Framework for task classification...33
Figure 3 Baddeley’s Working Memory Model (2003)...55
Figure 4 Anxiety and language processing...81
Figure 5 Kellogg’s model of writing...98
Chapter 1: Introduction
1.1 Background and rationale
Communicating in a foreign or second language (L2) involves exchanging a wide range of communicative intentions while adapting to different situations and contexts. Second language users’
production can be viewed as the result of a number of interacting factors such as the complexity of the communicative task they are performing, their cognitive abilities and language proficiency, affective characteristics such as anxiety or time constraints just to mention a few. Communicative intentions can be considered to be a series of discrete tasks such as: giving instructions or narrating a story. Research into the role of tasks and task features in second language acquisition (SLA) has received considerable attention in recent years (see Gilabert, 2007; Robinson & Gilabert 2007 for a review). Researching the effects of task-related variables on language production and language learning is essential to understand how task design and task sequencing may enhance language learning and how tasks may be used and exploited effectively in task-based syllabi. For these reasons, task characteristics have been in the focus of task-based language learning and teaching (TBLT) research. Researchers have studied tasks from different perspectives including interactional (e.g., Révész, 2007) and cognitive, information-processing (e.g., Skehan, 2003; Robinson, 2007b; Gilabert, 2005). Studying the interactive and cognitive demands of communicative tasks and their effects on language production has both theoretical interest for SLA and pedagogic relevance for materials and syllabus design as it provides important insights into the processes underlying language learning and performance in an L2 while contributing to the development of a
framework for pedagogic decisions about the classification and sequencing of tasks in language teaching (Robinson, 1995, 2005b).
The research project reported here aimed to explore the effects of manipulating task complexity on linguistic performance from an information-processing perspective following the line of research which investigates the interplay of cognitive task complexity and other task factors including interactive and individual learner variables (Robinson, 2005b; Robinson & Gilabert, 2007). To achieve a deeper understanding of how cognitive task complexity and individual learner variables interact in written and oral communication, this research project used language production data from the same group of higher-intermediate level learners for both written and oral narrative tasks. The study focused on various general and task-specific measures of linguistic performance regarding the fluency, lexical richness, grammatical complexity and accuracy of learner output.
1.2 Motivation for the present research
As the review of the literature will show in Chapter 2, there is a scarcity of studies that investigate the role of cognitive complexity factors and individual differences in communicative task performance, and no research has been done on the differential effect of these variables on the quality of both written and spoken output. Therefore, research questions 2 to 3 address the impact of cognitive task complexity on L2 oral and written narrative production, while research questions 4 to 6 concern how certain ability factors, namely working memory capacity and different components of foreign language aptitude, as well as an affective variable: input, output and processing anxiety manifest their effects in tasks which make different conceptualization and linguistic formulation demands on language learners. For this purpose I
used two types of narrative tasks that differed with regard to whether the students were required to plan the plot of their story.
This dissertation also aimed to discover differences in linguistic performance on the narrative tasks across modalities. My goal was to gain further insights into differences in spoken and written performance of L2 learners by using a wider range of variables than are traditionally included in the analysis of task performance. Most studies examining the subtle effects of the interaction of more than one task factor on L2 output (e.g., Kuiken & Vedder, 2007a, 2007b; Trebits & Kormos, 2009) conclude that beside general measures of L2 production, task-specific measures of more aspects of performance would reveal more precise information about how task design can be applied to direct learners’ attention to certain linguistic forms and how IDs may differentiate the way in which learners can benefit from the manipulation of certain task features. This research project intended to fill the gap of studies on the effects of both ability and affective individual variables influencing the cognitive processes involved in language learning and cognitive task complexity on spoken and written narrative performance. This study extended previous research in four ways. Firstly, the task types used in this study are unique in that both task types direct learners’ attention to certain grammatical and textual features (resource-directing effect) while the story narration task also involves resource-dispersing effects where learners’ attention is drawn away from the linguistic aspects of performance, in addition to the above-mentioned resource–directing effects. This makes the story narration task similar to real-life communicative tasks which usually exert both resource-directing and resource-dispersing effects. Secondly, this study aimed to connect the cognitive demands of tasks to individual differences modulating cognitive processes during language production.
Thirdly, this study compares the spoken and written output of the same population on the same task types making the comparative analysis of performance indicators possible across modalities. Last, but not least, in addition to traditionally applied general measures of task performance, this study used task-specific
measures in order to examine how language learners can benefit from the resource-directing aspects of these narrative tasks.
In a broader sense, the research reported in this dissertation wished to inform theoretical discussions of how task complexity affects L2 narrative performance in young adult learners by integrating language production theories, models of attention and the findings of task complexity research and to benefit language pedagogy in the area of task-based syllabus design.
1.3 Research questions
In line with the aims discussed above, the present study was guided by the following research questions:
(1) What are the characteristics of a B2 level sample of secondary school students taking part in a bilingual educational programme with regard to complex working memory capacity, foreign language aptitude and input, processing and output anxiety?
(2) How does manipulating cognitive task complexity affect general and task-specific measures of fluency, grammatical complexity, accuracy, lexical complexity in L2 narrative production?
(3) Do the effects of cognitive task complexity on L2 narrative performance differ in oral and written production?
(4) What are the effects of individual differences in working memory capacity, foreign language aptitude and input, processing and output anxiety on L2 narrative production?
(5) Do the individual variables of working memory capacity, foreign language aptitude and input, processing and output anxiety differentiate performance to the same extent in oral and written production?
(6) Do working memory capacity, foreign language aptitude and input, processing and output anxiety differentiate task performance to the same extent in the simple and the complex narrative tasks?
1.4 Overview of the dissertation
After the introduction of the aims of the research reported in this dissertation, Chapter 2 focuses on presenting the theoretical background by reviewing the relevant literature. The literature review begins with an overview of the most important concepts and developments in task-based language teaching including the notion of “task” and various task taxonomies. A discussion of the most influential models of task complexity forms an essential part of this section of the literature review. An extensive review of empirical studies within the field of task complexity complements this section. As this study also focuses on the role of individual differences (IDs) in task performance, the second section of this chapter introduces ID research with a particular focus on the constructs of complex working memory and phonological short-term memory, foreign language aptitude and anxiety, which are discussed in detail.
The third section of the literature review presents the most up-to-date theories of language production relative to both spoken and written modes of performance in order to provide a basis for the interpretation of the results in ensuing chapters.
Chapter 3 presents an extensive, in-depth overview of the empirical studies in the field of task-based research relevant to the present dissertation in order to situate the research reported here and to show the gap it intended to fill.
Chapter 4 of the dissertation describes the methods used to conduct the research for the study. The description of the research design and the participants is followed by the presentation of the instruments:
the narrative tasks used to elicit language data in both speaking and writing and the tests measuring the different ID variables listed above. This chapter ends with a discussion of linguistic performance measures
used to analyze students’ linguistic output, and a presentation of the statistical analyses and procedures applied in this study.
Chapters 5 to 7 present and discuss the findings of the study. Chapter 5 details the characteristics of the participants in terms of the cognitive and affective variables examined. The aim of this chapter is to map the characteristics of the research sample in order to aid the interpretation of the performance results analyzed in subsequent chapters.
Chapter 6 discusses the impact of cognitive task complexity and of spoken and written modes of performance on the quality of the language produced by the participants. This study used two types of narrative tasks imposing different cognitive demands on the participants, which they had to complete in both speaking and writing. The participants’ linguistic performance was analyzed and the results were discussed using a cognitive approach in terms of two influential models of task complexity: Skehan’s Trade-Off Hypothesis (Skehan & Foster, 2001; Skehan, 2009) and Robinson’s Cognition Hypothesis (2003a, 2005b).
Chapter 7 examines how IDs in working memory capacity, foreign language aptitude and anxiety modulate oral and written performance on the two task types. It examines the way in which ID variables mediate cognitive processes underlying L2 learners’ linguistic production by analyzing the interaction of IDs, task complexity and modes of performance. The results are presented within the framework of the Cognition Hypothesis (2003a), which makes particular claims as regards the interplay of ID variables and cognitive task complexity. The differences between the participants’ spoken and written performance are interpreted in the light of language production theories.
Chapter 8 intends to summarize the findings and draw the conclusions of this study by relating the results to the research questions asked in Chapter 1. Limitations and pedagogical implications as well as directions for future research are pointed out in Chapter 9.
Chapter 2: Theoretical background
2.1 Tasks in language learning and teaching
The aim of this chapter is to give an overview of the role of tasks in the context of L2 learning and teaching. After a brief discussion of why tasks have been in the focus of both SLA and pedagogic research, I will attempt to define the construct oftask as it is used in this study based on the abundant definitions available in the literature. Then, an analysis of task characteristics will follow with an emphasis of the concept of task complexity and influential models of task complexity as they relate to task performance.
Finally, the issue of measuring task performance with a view to tapping into the effects of task characteristics on L2 production will be outlined.
2.1.1 From communicative to task-based language teaching
Tasks have received much attention over the past two decades from researchers, teachers and test developers alike. At the root of this heightened interest which provides us today with a considerable amount of empirical data on tasks from multiple perspectives, we find the communicative approach to language teaching emerging from the 1970s (Skehan, 2003). Communicative language teaching shifted the focus of language teaching from language structures and grammar to meaning and the ability to communicate meaning much the same way as it happens in real-world communication when we make inquiries on the phone, write emails, set up a time to meet someone or order takeout from a nearby
restaurant, just to name a few examples. Backed by SLA research stressing the importance of exposure to and use of the L2 in language learning (Skehan, 2003; Willis & Willis, 2007; Samuda & Bygate, 2008), L2 teaching syllables and material designers started to develop tasks that can be used to engage learners in communicative activities, and therefore, generate an exchange and negotiation ofmeaning in the language classroom.
While the communicative approach in language teaching was generally embraced by research communities in the field of SLA and language pedagogy, and its propositions gradually found their way into the language classrooms via newly developed teaching materials and testing requirements, researchers were divided over the question of how interlanguage is driven forward when completing tasks, and which aspects of a task shall be manipulated in order to enhance L2 development in learners (Duff, 1986). It was argued that sufficient input and opportunities for output are necessary conditions for L2 learning, but a sustained structural development can only be attained if learners have an opportunity to tackle the linguistic issues that are problematic for them (Long & Robinson, 1998; Doughty, 2001). Therefore, while expressing meaning remains a central feature of the learning process, a focus on form is also necessary to integrate grammar instruction into TBLT (Long, 2000; Long & Robinson, 1998). Directing learners’ attention to form is important in order to avoid the fossilization of those incorrect forms which otherwise do not necessarily hinder communication (e.g., Albert, 2008).
From an interactional perspective, it was argued that interaction itself may foster interlanguage development through the process of what is called negotiation of meaning (Ellis, 2003; Foster, 1998). As they are performing a task, learners give and receive feedback from each other and/or the teacher in the form of comprehension checks and clarification requests. Then they must negotiate the meaning they wish to get across in an effort to avoid or repair communication breakdowns similarly to what happens in real-life communication. Following this reasoning, tasks should be designed to give learners plenty of
opportunities for the kind of interaction that would trigger the conversational moves mentioned above.
This should have a beneficial effect on both their pragmatic and grammar skills as during this process they need to pay more attention to noticing the gaps in their knowledge and to make changes to their utterances in order to achieve understanding. A relatively recent development within this line of task-based research concerns recasts, a conversational feature which typically occurs in dialogues between native and non-native speakers, or in the L2 classroom between the learners and their teacher. A recast is a kind of feedback which involves paraphrasing what someone said. The usefulness of the reactive recast is that it models the correct expression for the language learner and focuses their attention on form at a point in the conversation when it is the most relevant. Research in this tradition on the noticing and uptake of recasts have shown that it can facilitate L2 development (e.g., Révész, 2007, 2009; Mackey & Philp, 1998;
Long, 2007), although it has also received some critism on grounds that their potential may not always be realized as they may irritate language learners (Aston, 1986), and that neither recasts nor negotiations of meaning occur in L2 classrooms in the same way as they do in laboratory conditions which means they may not have the same beneficial effects (Foster, 1998; Lyster & Ranta, 1997).
Experimental studies exploring tasks from a cognitive perspective focus on the psychological processes involved in task performance, and they offer a different approach to achieving a focus on form.
This line of research focuses on mapping the effects of tasks on learners’ performance and examining how manipulating certain task features can direct learners’ attention to form. Areas which have prompted studies include the information-processing demands of tasks and the use of attentional resources available to learners when completing tasks (Skehan & Foster, 1999; Robinson, 1995; Gilabert, 2007), the conditions under which tasks are carried out, such as the availability of planning time or familiarity with the task (Foster & Skehan 1996; Ortega, 1999; Gilabert, 2005), and individual differences that influence
how task difficulty is perceived by the learners, for example working memory capacity and language aptitude (Trebits & Kormos, 2009; Niwa, 2000) or proficiency level (Kuiken & Vedder, 2007b).
A more pedagogical orientation to research into tasks deals with issues concerning the effective organization of tasks in the language syllabi and individual lesson plans (Buck, 2009), the use of tasks in different ways for various pedagogical purposes within a sequence of language instruction (Samuda &
Bygate, 2008), and teachers’ interpretation and re-shaping of the tasks as they use them (Andon, 2009).
Some
authors give practical advice to teachers regarding the structuring of task sequences in the language classroom (Willis & Willis, 2007, 2009). They suggest that pre-task activities be used to prepare the ground for tasks by priming certain linguistic features, and that follow-up tasks be designed in order to recycle the language items that came into focus during the completion of the task, which will concentrate the learners’ attention on the relevant linguistic forms and help consolidate their use. The most important pedagogical relevance of research into task features probably lies in its potential to contribute to task sequencing decisions in L2 syllabi (Robinson & Gilabert, 2007).
This particular study follows the line of research which investigates the information-processing demands of tasks, and it aims to contribute to our understanding of how the manipulation of certain task features affecting their cognitive complexity can influence L2 narrative production. Therefore, in what follows I intend to define how the construct of task is understood in TBLT, and outline the existing frameworks of task characteristics, which will bring us closer to the concept of task complexity, a key element of my research.
2.1.2 Defining “task”
2.1.2.1 Task definitions
No account of the most important developments in task-based language teaching and learning (TBLT/TBLL) would be complete without a brief summary of attempts to define the construct oftask. As this section will show, numerous definitions have been proposed, most of which highlight different aspects of the construct as they relate to various directions of research within the field of TBLT.
Long (1985, p. 19) provides the most general definition which emphasizes that tasks are rooted in
“real-world” activities:
A task is a piece of work undertaken for oneself or for others, freely or for some reward. Thus examples of tasks include painting a fence, dressing a child…In other words, by “task” is meant the hundred and one things peopledo in everyday life, at work, at play, and in between.
This definition is in line with the communicative approach promoting that the tasks used in language teaching should reflectreal-life communication. Some definitions underline the importance of thegoalor outcome a task aims to achieve (Willis, 1996). Another characteristic feature that definitions frequently highlight is that tasks are centered on conveying meaning rather than on practising linguistic forms (Nunan, 1989). Prabhu (1987), Breen (1987) and Crookes (1989) define task as a pedagogical construct and link it to work done in the language classroom. Skehan’s definition seems to be the most complete as it tries to bring together almost all the features mentioned above (1998, p. 95):
A task is an activity in which meaning is primary; learners are not given other people’s meanings to regurgitate; there is some sort of relationship to comparable real-world activities; task completion has some priority; the assessment of the task is in terms of outcome.
The different perspectives taken by the definitions listed above point out an important distinction to be made between real-world (target) tasks and pedagogic tasks. Long’s broad definition concerns real-world tasks, some of which are not even linguistic tasks, while Skehan’s clearly refers to pedagogic tasks in language classrooms. The success of communicative instruction with a focus-on-form in L2 teaching is largely due to the fact that this approach connects pedagogic tasks to the real world that is, to specific tasks that are present in real-life communication. Real-world target tasks are often incorporated into communicative and task-based syllabi on both general and ESP courses, in which case they may be broken down into a sequence of tasks or sub-tasks (Willis & Willis, 2007) (See section 2.1.2 for more on task-based syllabus design). As Willis and Willis (2007) point out, however, some tasks do not mirror the real world as far as themeaning conveyed by them is concerned (e.g., language games), and yet they hold considerable potential for contributing to interlanguage development.
The termpedagogic task also implies the involvement of the learners and teachers in the dynamics of its use as a pedagogic tool: a task will not have the same effect on learners’ performance and learning regardless of the learners and teachers themselves, it will evolve through their interpretation and choices.
This pedagogic aspect of tasks is already present in Prabhu (1987) as well in more recent research into teachers’ uses of tasks (e.g., Samuda et al., 2009).
Still within the pedagogic framework, Candlin (1987) and Swales (1990, p. 75) mention another feature of tasks, namely that they “are ‘sequenceable’ ... although there currently exist considerable doubts as to the validity of the criteria by which tasks can be ordered”. The issue of task grading and sequencing - a major problem in task-based syllabus design and therefore language teaching in general - was picked up by researchers and has ever since been a serious motivation for research concentrating on the effects of task features and their manipulation on language learning (Gilabert, 2005, 2007; Robinson, 2001b;
Skehan & Foster, 1999). In a broader sense the study reported in this dissertation also intends to benefit language pedagogy in the area of task sequencing and syllabus design.
2.1.2 Task types and task-based syllabi
The diversity of orientations within TBLT reflected in the definitions cited above is also apparent in the literature on task-based syllabus design (for example: Long & Crookes, 1993; Willis & Willis, 2007).
The most important and intriguing question behind the different approaches, however, remains the same:
How can task design and task sequencing be made more effective in promoting learning? Task-based instruction approaches this question from a psycholinguistic angle. By combining a focus on meaning with a focus onform during opportunities for L2 output, TBLT is believed to provide an optimal platform for L2 learning (Révész, 2007). However, as TBLT focuses on fostering the L2 acquisition process by engaging the learner to operate on language and use it meaningfully rather than by teaching linguistic units, in order to answer the above question it is necessary to understand how tasks affect the way learners use the L2 (Long & Crookes, 1993). A taxonomy of task features is necessary to make research data on task effects comparable and to provide guidance as to ways in which TBLT can be implemented in the L2 classroom (Skehan, 1998; Long & Crookes, 1993; Robinson, 2007b).
The search for a generally acceptable taxonomy has inspired research into task features from different theoretical and practical orientations. As Table 1 below shows, task labels originating from classroom research and practice are rather diverse and can be confusing because the same label may, in fact, refer to different realizations of a task. For example, a task labeled as “problem-solving” may involve individual or pairwork, split or shared information, in which case it may also be referred to as
“information gap” or “jigsaw” task in various sources. Therefore, the problem with task types seems to be that due to a lack of criteria which could serve as a basis for comparison, it is difficult to assess their
relative difficulty. Long and Crookes (1993) also raise the problem of finiteness in connection with task types which refers to how various tasks overlap and may be divided into several subtasks which makes it difficult to tell where one task ends and the next task begins.
The interactionist and information-processing research agendas (also shown in Table 1) have, thus, been motivated by the same goal that is, rather than focusing on task types, they seek to understand and group the various task characteristics in a comprehensive framework which allows researching their interactions and effects on L2 production. These findings could then be highly relevant for syllabus design and could, in turn, motivate task-sequencing decisions.
Table 1. Task types and task characteristics in different research agendas
Pedagogic approach Interactionist approach Information-processing approach
e.g., Pica et al, 1993; Samuda, 2001; Willis & Willis, 2007
e.g., Duff, 1986;
Rahimpour, 1997
e.g., Skehan, 1998; Robinson, 2001b
· Discussion/opinion exchange
· Prediction
· Jigsaw
· Information-gap
· Listing
· Ordering/sorting
· Matching
· Comparing/contrasting
· Decision-making
· Problem-solving
· Storytelling
· Projects/creative tasks
· Focused tasks
· One-way/two-way
· Open/closed
· Convergent/divergent
· Split/shared information
· Group/pair
· Familiar/unfamiliar task type or topic
· Planning time/No planning time
· Here-and-now/there-a nd-then
· Few elements/Many elements to relate to
2.1.3 Models of task complexity and task taxonomies
In TBLTtasks are considered the basic units of instruction replacing traditional linguistic units in syllabus design. In task-based syllabi tasks should be sequenced to increasingly approximate the demands of real-world target tasks in order to prepare L2 learners for real-life linguistic and communicative challenges (Robinson, 2005b). Researching how task features contribute to task complexity is essential in order to establish the criteria that can be used to make pedagogic decisions regarding task sequencing.
Over the past decades several attempts have been made to develop comprehensive taxonomies or frameworks of task characteristics (Pica, Kanagy, & Falodun, 1993; Duff, 1986; Prabhu, 1987; Brown et al., 1984; Candlin, 1987; Skehan, 1998; Robinson, 2001b). These taxonomies - reviewed in this section - attempt to pinpoint task features that could be manipulated to achieve different degrees of task complexity.
Earlier attempts to establish a set of grading/sequencing criteria for tasks from simple to complex were less comprehensive and more or less speculative (Skehan, 1998). One of the earliest proposals came from Brown et al. (1984) who distinguished between two dimensions of task difficulty. Along the first dimension there are three types of task ascending in difficulty: static, dynamic and abstract. The difficulty represented by this dimension concerns the type of information available to the learner while performing the task. For example a static task involves concrete and available information to be exchanged, e.g., a map for giving instructions, while in a dynamic task such as storytelling the content to be communicated is available, but there are changes in events or characters which forces the learner to give precise descriptions and use consistent language. An abstract task (e.g., an opinion exchange) is considered to be the most complex along this dimension as it involves reasoning and talking about and making connections between abstract ideas while having to “invent” message content as well, because in this type of task the
stimulus material does not contain the message that the speaker will have to communicate. Besides their degree of abstractness, tasks can increase in complexity based on the number of elements to relate to and the relationships between these elements (e.g., a story with one or two characters versus a story with several characters and flashbacks to earlier events). Brown et al. (1984) concentrate solely on the cognitive aspects of task complexity, and as we will see, later models will incorporate his suggestions into theirs.
Another proposal for a framework of task difficulty came from Candlin (1987), whose set of criteria is more comprehensive in the sense that besides cognitive difficulty factors (referred to as cognitive load, particularity and generalizability, and process continuity), he included other factors relating to the interaction (communicative stress), and the linguistic code itself (code complexity and interpretative density).
Prabhu (1987, p. 47) defines his criteria as “rough measures of cognitive complexity”. His proposal of grading criteria comes from the Bangalore Project in India, a British Council initiative that took place between 1974 and 1984. His goal was to develop a communication-oriented teaching methodology where language learning would be incidental to the execution of the task as tasks would be designed to “let the language relevant to the task to come into play” (Prabhu, 1987, p. 276). His criteria included: the amount of information (drawing on Brown’s idea of the number of elements involved), the amount of reasoning, the degree of precision (a similar idea can be found in Brown et al.’s understanding ofdynamic tasks), the degree of familiarity (the same idea can be found in Candlin (1987) under the nameprocess continuity), and the degree of abstractness (cf. Brown et al.’sabstract tasks).
Table 2 summarizes the grading criteria for assessing task difficulty put forward in the proposals reviewed thus far. It is apparent that these earlier proposals mostly focused on factors which may increase the cognitive complexity of a task. As we will see, these criteria have also found their way into the more
recent and more comprehensive task complexity models, which do not only seek to establish a list of criteria, but also address the possible relationships between the different categories of task difficulty factors.
Table 2. Earlier proposals of task grading criteria
(The task features recurring in more than one proposal are set inbold)
Linguistic code Cognitive factors Interactive
factors Brown et al.
(1984)
Concrete information vs abstract task;
Dynamic tasks, precision of expression;
Few vs many elements Candlin (1987) Complexity of linguistic
code;
Complexity of
operations to be carried out on the code
Complexity of content;
Few vs many elements;
Process continuity, familiarity of task type;
Particularity and generalizability, clarity of goal of task
Communicative stress,
familiarity of the interlocutor
Prabhu (1987) Degree of abstractness;
Few vs many elements;
Amount of reasoning;
Familiarity of task;
Degree of precision
Synthesizing these earlier task sequencing criteria and adding other task features to account for task difficulty, Skehan (1998) and Robinson (2001b) developed the most detailed and influential task taxonomies to date distinguishing between several difficulty factors including linguistic, cognitive, communicative, interactive, and learner variables. Skehan’s model of task difficulty attempts to overcome the limitations of earlier frameworks by proposing a three-way distinction for the analysis of tasks. The three dimensions proposed by Skehan (1998), i.e.: code (linguistic) complexity, cognitive complexity and communicative stress, correspond to three crucial elements influencing task performance: language, thinking and performance conditions (see Figure 1 for details). Skehan (1998, 2007) views task difficulty
as a construct that is directly connected to the amount of attention the execution of a task demands from the learners. Tasks made more difficult along any of the proposed dimensions will require more attention, consequently, the elements of task difficulty may only be used to direct learners’ attention to certain areas of performance at the expense of others. Skehan (1998, 2007, 2009) suggests that empirical findings on the effects of task manipulations along the proposed dimensions should determine decisions regarding syllabus design with a view to attaining a balanced development in three areas of performance:
complexity, accuracy and fluency (see section 2.1.5 for more on the measures of L2 production in TBLT and SLA research).
Figure 1
Skehan’s model of task difficulty
Code complexity Cognitive complexity Cognitive
familiarity
Cognitive processing
Communicative stress
Linguistic
complexity, variety
Topic familiarity Information organization
Time pressure
Vocabulary load and variety
Discourse/genre familiarity
Amount of
‘computation’
Speed of presentation
Redundancy and density
Task familiarity Clarity and sufficiency of information
Number of participants
Information type Length of texts Type of response Opportunities to control interaction
Note. Based on Skehan, 1998.
As can be seen from Figure 1 above, Skehan’s model is more elaborate and comprehensive than earlier models of task complexity while it also incorporates certain elements from them (e.g., task familiarity, code complexity, concrete vs. abstract information).
Robinson’s Triadic Componential Framework (2001b, 2003a, 2005b) is also rooted in the idea that research results concerning the effects of the manipulation of task features on L2 production and, possibly interlanguage development, should be transferred to language pedagogy. Building on theories from the fields of cognitive psychology, psycholinguistics and SLA, he attempts to create a framework that can house and synthesize prior proposals in a multidimensional system that could serve as a basis for
“theoretically motivated, empirically sustainable, and pedagogically feasible sequencing criteria”
(Robinson, 2007b, p. 27). In Robinson’s model (see Figure 2), task complexity refers to the information-processing demands the task imposes on the learners. This dimension accounts for within-participant variation that is, how the same learner may perform differently on simple versus complex tasks. Task condition covers the interactional demands of tasks while task difficulty accounts for learner factors that affect how learners perceive the tasks through the filter of their own subjective qualities that they bring to the task (e.g., working memory capacity, language proficiency, anxiety). This dimension is responsible for between-learner variation in task performance as individual differences (IDs) have a powerful impact on L2 production (see section 2.3 for a comprehensive overview).
Figure 2
Robinson’s Triadic Componential Framework for task classification Task Complexity
(Cognitive factors)
Task Condition (Interactive factors)
Task Difficulty (Learner Factors) Resource-directing variables Participation variables Ability variables +/- here-and-now
+/- few elements +/- spatial reasoning +/- causal reasoning +/- intentional reasoning +/- perspective taking
+/- open solution +/- one-way flow +/- convergent solution +/- few participants
+/- few contributions needed +/- negotiation
high/low working memory high/low reasoning
high/low task-switching high/low aptitude
high/low field independence high/low mind/intention reading Resource-dispersing variables Participant variables Affective variables
+/- planning time +/- single task +/- task structure +/- few steps
+/- independency of steps +/- prior knowledge
+/- same proficiency +/- same gender +/- familiar
+/-shared content knowledge +/- equal status and role +/-shared cultural knowledge
high/low openness to experience high/low control of emotions high/low motivation
high/low anxiety
high/low willingness-to-communicate high/low self-efficacy
Note. From "Criteria for grading and sequencing pedagogic tasks" by P. Robinson, 2007, In M. P. Garcia Mayo (Ed.)Investigating tasks in formal language learning (p. 14). Clevedon: Multilingual Matters.
Skehan (2007) questions the validity of task difficulty as the basis for task sequencing decisions due to the fact that in his view the problem of task difficulty is still unresolved. He does not specify which of the proposed three task difficulty dimensions could possibly be used to inform sequencing decisions. In contrast, Robinson (2001b, 2003a, 2005b) argues that cognitive task complexity should be used to that
end because the interactive and learner factors are dependent on individual learners and, therefore, cannot be predicted. These latter factors may, however, be used by the teacher to make local, on-line decisions during the course or can be assessed by needs analysis and learner questionnaires. Cognitive task complexity in Robinson’s framework involves resource-directing and resource-dispersing variables determining the coordination of attentional resources while performing a task. Resource-directing variables direct learners’ attention to certain linguistic features that are necessary for the successful execution of the task. For example, having to narrate a story in the past will direct students’ attention to time expressions and past verb tenses. Resource-dispersing variables, however, use students’ attentional and memory resources without directing them to any linguistic aspect in particular, for example having to write an essay about a topic that one is not familiar with will make huge demands on memory resources.
Real-world communicative tasks often involve both dimensions of cognitive task complexity: for example, simply answering a question about what you did over the weekend in L2 would involve resource-directing variables: e.g.: use of past tense, as well as resource-dispersing variables: e.g.: having to improvise with no preparation time.
Robinson (2001b, 2003a, 2005b) also addresses the problem of how the different dimensions underlying task complexity interact and may produce combined effects, an issue, prior frameworks neglected. He theorizes that IDs contributing to perceived task difficulty differentiate task performance to a greater extent as tasks increase in complexity. In other words, between-learner variety in L2 output will be greater on more complex tasks.
2.1.4 Task complexity and the allocation of attention
One of the most important issues in TBLT research concerns the influence of cognitive task complexity on the allocation of attention during task performance and its consequential effects on L2
production. In order to understand how the current models of task complexity build on research on attention in order to accomodate research findings and make predictions regarding L2 performance, this section will begin with an overview of the most prevalent models of attention in cognitive psychology.
Then influential theories of how attentional demand affects L2 task output will be presented along with specific claims made by those theories regarding the effects of pedagogic task demands.
2.1.4.1 Attention and task performance
Attention to linguistic input is considered to be essential for L2 learning as a key process underlying selection and noticing (Robinson, 2003b; Schmidt, 2001). Similarly, attentional mechanisms are also at work during L2 production. In this sense attention can be viewed as a process serving the information-processing sequence that we call task performance, from perception to the execution and monitoring of a response (Eysenck & Keane, 2000). In line with the purpose of this study, this section presents a cognitive-level description of the attentional processes involved in L2 performance. In this context task performance in a second language can be understood as “the skilled deployment of existing knowledge to achieve task goals” (Robinson, 2003b, p. 632). The theoretical models of attention presented in the below attempt to describe how attentional resources are structured and drawn on during the completion of a task.
Information-processing involves three stages: perceptual encoding, central processing and responding (Eysenck & Keane, 2000). First, incoming information is perceived and selected for further processing, then, once the selected information is processed in working memory, a response is formulated and executed. These stages of the information-processing sequence are served by two aspects of the concept of attention:selection of what we would like to further process of all the incoming information and the allocation of attentional resources during information processing and response formulation.
According to several lines of research attention is limited in capacity (Kahnemann, 1973; Wickens, 2007).
Attentional resources are also responsible for sustained attention, usually described as the effort one invests into the execution of a particular task (Robinson, 2003b; Wickens, 2007).
L2 performance and learning involve both the selective or ‘filter’ and the ‘resource’ or ‘fuel’
aspects of attention (Wickens, 2007). Selective attention in the SLA research community is considered to be necessary “as a means of action control [...] Actions are responses to task demands, and allocation of attention to input with the goal of meeting these
demands is the result of control processes operationalized in short-term/working memory.”
(Robinson, 2003b, p. 634).
Research studies comparing attention to the concepts of ‘capacity’, ‘resource’ or ‘fuel’ implies two important assumptions: 1) attention serves and enables the full sequence of information-processing activities, and 2) attention is limited and can be depleted by the demands of the task or tasks being executed (Robinson, 2003b; Eysenck & Keane, 2000; Wickens, 2007).
As section 2.1.3 on task characteristics has shown, tasks vary in the cognitive and interactive demands they impose on our attention. Complex tasks drain our attentional resources to a greater extent than simple tasks as performing two tasks simultaneously and dividing our attention between them can be more difficult than performing one single task. Therefore, the same person may perform differently on a task depending on its degree of complexity and/or whether more than one task needs to be attended to at once. That is why, in the SLA context as well, attentional task demands are considered to be a factor contributing to within-learner performance and interlanguage variation (Robinson, 2003a). There is general agreement between researchers in both cognitive psychology and SLA that tasks demands vary and draw differently on our attentional resources accordingly, but conflicting propositions have been advanced regarding the concept of attentional resource pools and how they work.
The single capacity view (Kahneman, 1973), as its name suggests, argues that there is a single volume of attention, limited in capacity, which can be drawn on during task performance. Although attentional capacity is limited, its limits can be extended if the level of effort or motivation is high because of the physiological arousal effort these may induce. To account for breakdowns and success in dual task performance, this theory argues that two tasks can be done simultaneously if the combined demands of the two tasks do not exceed the total resources of the available attentional capacity. Single capacity theories have been criticized on grounds that they cannot explain how attention is divided during dual or multiple task performance as they rely solely on the difficulty level of tasks in their arguments.
Based on an analysis of dual task interference data Wickens (2007) proposed a multiple resource model of attention, which attempts to account for the differences between the ways tasks interfere with one another by analyzing their inherent structure along the various dimensions of the information-processing sequence. For example, driving a car requires visual/spatial processing and a manual/spatial response while maintaining a conversation calls for auditory processing and a vocal/verbal response. The multiple resource model suggests that attentional capacity comprises several dichotomous resource pools along the dimensions of the information-processing sequence. Three of the proposed four dimensions are relevant for language behaviour, namely 1) stages of processing which includes perception/cognition and response, 2)modalities of processing including visual and auditory, and 3)codes of processing and responding referring to verbal, vocal or spatial. According to Wickens (2007) each of the dimensions of task structure draws on its corresponding attentional resource pool, and two tasks executed simultaneously and drawing on the same resource pool enter into competition for attention. Therefore, performance on each would probably deteriorate, although it has been noted that practice and automatization processes may significantly improve task performance by reducing the amount of attention necessary for the execution of the tasks. However, when two tasks use attention from different resource pools, they do not enter into
competition, which explains why driving and singing along with the radio may be easier to do than maintaining a conversation and listening to the news at the same time.
A key element in Wickens’ model is the identification of the dimensions differentiating between the various resource pools since this is what his explanation of divided attention during dual task performance hinges on. Research into task interference has provided evidence which shows that the identification and definition of Wickens’ dimensions would have to be made more specific to be able accommodate all the findings. For example performing spelling and arithmetic tasks orally would both be cast in the verbal/auditory perception - vocal/verbal response pools respectively, and yet performing a spelling and an arithmetic task versus performing two arithmetic tasks simultaneously yielded different performance results (Hirst & Kalmar, 1987).
Another issue raised in connection with both Kahneman’s and Wickens’ models concerns the basic assumption in both models that attentional capacity is limited. Subsequent ‘interference’ models (e.g., Navon, 1989; Sanders, 1998) do not resort to the argument of attentional capacity limitations when attempting to explain deteriorating performance in dual- or multi-tasking situations. Instead, picking up on Wickens’ suggestion of multiple resource pools, interference models propose that reduced performance is a result of interference and confusion caused by shifts of attention between tasks. Higher task demands, characterized by a greater amount of stimuli/input and many or similar response alternatives leads to a competition for attention between the same types of codes or to cross-talk between them (Sanders, 1998).
Thus the current trend in attentional theories is to move away from the idea of attention as limited in capacity towards interference during the process of resource allocation, all the while maintaining Wickens’ idea of multiple attentional resource pools.
