Journal of Neurolinguistics 24 (2011) 556–570

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jneurol ing

Early strategies of elementary school children’s single wordreading

Sven Lindberg a,c,*,1, Jan Lonnemann a,b, Janosch Linkersdörfer a,b,Eva Biermeyer e, Claudia Mähler d, Marcus Hasselhorn a,b,c,Martin Lehmann a,c,1

aGerman Institute for International Educational Research (DIPF), Frankfurt, Germanyb Institute for Psychology, Goethe University, Frankfurt, GermanycCenter for Individual Development and Adaptive Education of Children at Risk (IDeA), Frankfurt, Germanyd Institute for Psychology, University of Hildesheim, Germanye Institute for Psychology of Special Education, College of Education of Heidelberg, Germany

a r t i c l e i n f o

Article history:Received 1 July 2010Received in revised form 2 February 2011Accepted 14 February 2011

Keywords:ReadingStrategiesVariabilityOverlapping Waves Model

* Corresponding author. Schloßstr. 29, 60486 FraE-mail address: s.lindberg@idea-frankfurt.eu (S

1 Shared first author.

0911-6044/$ – see front matter � 2011 Elsevier Ltdoi:10.1016/j.jneuroling.2011.02.003

a b s t r a c t

According to the Overlapping Waves Model, children’s strategy usein performing academic skills is variable and adaptive and changesgradually with age and experience. In the context of children’snumerical and arithmetical development, several findings confirmthe assumptions of the model. In this study, elementary schoolchildren in 2nd (n ¼ 30) and 4th (n ¼ 28) grade, with comparable IQand reading achievement scores were confronted with differentsingle word tasks (common and uncommon words, word-similarand -dissimilar pseudowords) to trigger different reading strate-gies. Strategy behavior was identified by video analysis and chil-dren’s self-report. The analyses of the data confirm the validity ofthe Overlapping Waves Model in the context of single wordreading. Children in both grades showed variable and multipleusage of strategies and reacted adaptively when reading words ofthe different categories. Moreover, older children used moreelaborated strategies and were more efficient in their strategychoice.

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nkfurt, Germany. Tel.: þ49 69 24708 224; fax: þ49 69 24708 216.. Lindberg).

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1. Introduction

Children’s development of thinking often has been described by using the metaphor of differentdevelopmental stages that succeed each other in a predetermined way (for an overview, see Siegler &Alibali, 2004). As a consequence, children’s thinkingwould develop sequentially andwith the necessityof passing distinct early stages before reaching qualitatively higher stages. However, whenwe observechildren’s behavior in everyday life it is evident that they are able and eager to use a variety of differentapproaches to solve a single problem. More specifically, most of the time different alternative solutionsare competing with each other. The same observations can be made in school related skills, such asarithmetic, spelling, and reading. Here, children are confronted with alternative options when solvinga specific task. In the present study, we focus on the analysis of single word reading strategies inGerman 2nd and 4th grade elementary school children in the context of the Overlapping Waves Model(Siegler, 1995) by using a single word-reading task that was arranged to trigger different readingstrategies. Siegler’s Overlapping Waves Model provides an explicit description of phenomena under-lying the diversity in children’s thinking development. The model states that at any time a child coulduse more than one strategy type to solve the demands of any given task and that children’s thinking ischaracterized by the key features of cognition: wide variability, adaptive choice, and gradual change instrategy choice over time. Strategies emerge, persist, change, interact or coexist at one time and overtime – the probability of their usage and occurrence can be sketched as ascending, consistent anddecreasing graphs in a diagram, which wavelike overlap one another. The empirical basis of the modeland its assumptions were built on findings in algorithmic domains. Recently, a few studies haveattempted to expand the empirical justification of the model to non-algorithmic domains such asspelling and reading. Yet, research results in these domains are not very numerous and thereforelimited to specific material and participants (e.g. unvaried word-lists and very young children).

1.1. Assumptions of the Overlapping Waves Model

1.1.1. VariabilityWhenwe observe children’s behavior during a task trial-by-trial, multiple strategies can be detected

both over the various trials but evenwithin any single trial. Variability in strategy usage can vary fromone child to the next and even within any child in the course of time (Siegler, 1991). Such multiplestrategy use was found in several domains of applied learning and problem solving and across differentage groups ranging from infants to adults (Adolph, Eppler, & Gibson, 1993; Farrington-Flint, Vanuxem-Cotterill, & Stiller, 2009; Siegler&Shrager,1984). Especially during the acquisition of newskillswithin anunknown domain, several competing and/or alternative and complement strategies are present inaperson’s attempt tomaster a specific task. Variability in children’s strategyuse is characteristic for skillsin academic development: arithmetic (Canobi, 2004; Canobi, Reeve, & Pattison, 2003; Lemaire& Siegler,1995; Siegler&Shrager,1984), reading (Farrington-Flint, Coyne, Stiller, &Heath, 2008; Farrington-Flint&Wood, 2007; Jorm& Share,1983) and spelling (Farrington-Flint et al., 2008; Kwong & Varnhagen, 2005;Rittle-johnson & Siegler, 1999). In all these domains children rarely apply only one approach to solvea task: in fact, they use several different approaches to attaining a certain goal. Thereby, childrenconsistently create novel learning experiences they can benefit from.

1.1.2. Adaptive choiceNearly all learning related tasks are most efficiently mastered by an automated advanced strategy or

procedure (such as multiplication tables). In this way facts can be directly retrieved from memory(6 � 8 ¼ 48) and no alternative approaches have to be conducted. However, to master the essentialdemands of a domain, it is crucial to acquire and exhibit an adequate repertoire of strategies that doesnot only rely on a solely automated retrieval of facts and therefore allows a person to adapt to therequirements of a new task (if 5 � 8 ¼ 40 than 6 � 8 ¼ 5 � 8 þ 8). Those strategies are called backupstrategies and they are less effective and more time-consuming than the strategy of direct retrieval.Even though children are already able to use retrieval to solve a task, they often do not use it but rely onbackup strategies. That behavior is closely related to the perceived characteristics of a specific task: ineasy and familiar tasks, children often exhibit effective and fast retrieval, while in difficult problems,

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they tend to select the slower and more extensive backup strategies (Siegler, 1986) in order to producethe correct solution. Thus, children choose from the pool of strategies available to them adaptively tosolve a problem in a way that is convenient for themselves and that allows them to be accurate even ifthis implies that they will need more time (Lemaire & Siegler, 1995; Siegler, 1996). Additionally, chil-dren resort to their strategy repertoire, but they becomemore andmore effective in selecting the fasterandmore accurate strategies in the course of time. Here, sensitivity for task characteristics and strategycharacteristics may play a crucial role for an increasingly competent strategy choice (Flavell, 1978;Hasselhorn, 1992).

1.1.3. Gradual changeThroughout the acquisition of different skills within a domain, children constantly progress toward

faster and more accurate performance. Siegler (1996, 2002) postulates four aspects which can producechange: (1) introduction of new, more advanced, strategies, (2) increasing use of the more advancedstrategies from among those that are already known, (3) increasingly effective execution of strategies,and (4) more adaptive choices among strategies. Due to that gradual development, the skill level willcontinue to improve over time (e.g. quick retrieval of partial and final results).

1.2. Strategies in reading & arithmetic

The Overlapping Waves Model originates from research in domains which enable the use ofalgorithmic strategies. Such strategies yield directly a correct answer if they are applied accurately. Inarithmetic operations, for example, only one right answer is possible. No matter what strategy wasused, 4 þ 4 has to be 8. In other domains such as reading and writing, a correct answer cannot be sodistinctly defined. Knowing a word and its semantic meaning does not automatically lead to a 100%correct answer. Although a person is aware of the orthographic rules and phonological features of theirlanguage, a correct spelling or articulation of a specific word is not guaranteed (Rittle-johnson &Siegler, 1999). Nevertheless, recent studies have shown that the assumptions of the OverlappingWaves Model can be transferred to reading and spelling in the English language (Farrington-Flint et al.,2008; Farrington-Flint et al., 2008; Farrington-Flint et al., 2009; Farrington-Flint &Wood, 2007; Siegler,1988). It is important to emphasize that in these studies, not only indicators were found for variability,adaptive choice, and gradual change in children’s strategy use, but also a direct retrieval of facts forreading and writing skills.

The retrieval of facts is one of the most important competencies for fluent and automated readingand quick and accurate calculation. During the acquisition of arithmetic and reading skills, childrenapply a range of backup strategies before they rely on retrieving the results from memory. Whenapplied, retrieval is related to a better and faster performance in arithmetic (Boulton-Lewis & Tait,1994; Goldman, Mertz, & Pellegrino, 1989) and also in reading performance (Farrington-Flint et al.,2008; Farrington-Flint et al., 2009; Share, 1999, 1995).

In conclusion, the above-mentioned findings underline that it is general possible to transfer theOverlapping Waves Model from algorithmic domains such as arithmetic to the non-algorithmicdomain of reading. Farrington-Flint et al. (2008) presented a first attempt to transfer the OverlappingWaves Model to the reading domain. In their study, five to seven year old children were asked to readreal word items with different length and frequency on three separate occasions. Variability was foundin children’s self-reported reading strategies and over time, the children relied less on phonologicalstrategies and moved towards direct retrieval. We should mention that this study emphasized the roleof retrieval and focused less on the differentiation of backup strategies. Moreover, the used materialwas only slightly manipulated to demonstrate the children’s learning effects across the three separatereading occasions. The analysis of different reading strategies with regard to specific word material istherefore considerably limited. In addition, only early readers participated in this study allowing for noconclusions regarding older and more experienced elementary school readers. Despite its novelcontribution, the study left a few questions to be answered. As claimed by the authors themselves,studies that also focus on children at the end of elementary school and further variations in wordmaterial and strategy classification will be required.

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Besides the demonstrated importance of fact retrieval it is essential to closely examine children’sbackup strategies in reading and their ability to adapt to different tasks and how their proceedingsgradually changewith increasing age. Backup strategies are fundamental to children’s learning. Startingwith basal approaches, trial and error and assistance from others, children acquire, use and combinemore andmore different strategies. Slow, error-prone and laborious strategies decrease and faster,moreaccurate and appropriate strategies increase. Retrieval involvement, even only in parts, emerges duringthe process of strategy choice and usage and generally, skills become more automated. Nevertheless,both backup and retrieval can produce correct and incorrect results. Therefore, an adequate analysis ofchildren’s backup, retrieval and combined strategies and their successful and unsuccessful accom-plishment is indispensable when conducting a study in a domain that is scarcely explored yet.

The assumptions of the overlapping waves model can be also recognized in current reading develop-ment theories. In contrast to traditional stage models (Frith, 1985; Marsh, Friedman, Welch, & Desberg,1981) recent models of reading development allow and emphasize the occurrence of flexible and vari-able processes during reading acquisition. The mediated phase model (Ehri, 1995, 1998) for instancedefines different phases of alphabetical processing (pre-, partial-, full- and consolidated alphabetic) andunderlines that these phases do not have to follow a strict predefined order. It is rather assumed that theattributes of thedifferent phases canoccur, change and interact in the progress of reading acquisition. Thatmeans that depending on the experiences and preconditions of a child, differentwords can be decoded oractually be read by using different procedures. Regarding to this, words can be read for example by theidentificationof lettercues, by letter-soundcorrespondence,byusinganalogiesorfinallybydirect retrieval(Ehri, 2005). In accordance with the overlapping waves model children will retrieve words they alreadyhave stored inmemoryanduse alternative (orbackup)approacheswhen theyare confrontedwithdifficultor unknownwords.Moreover, the self-teachingmodel (Share,1995,1999) that describes the developmentof children’s word-reading development is also compatiblewith above-mentioned processes. Themodel,however, refers firstly to the impact of orthographic and phonological processes in reading comparable tothedual-routemodel ofColtheart, Curtis,Atkins, andHaller (1993). The spellingof letternamesand theuseof sounds to obtain thepronunciationof awordbuild the foundation to store orthographic representationsinmemory. Hence, the characteristics of aword are decisive for children’s choice of reading strategy (Jorm&Share,1983; Share,1995,1999). Accordingly, the self-teachingmodel givesword-specific explanations ofchildren’s strategy usage: (1) familiar words are more likely to be retrieved from memory due to theidentification of orthographic aspects by applying only minimal phonological processing, (2) whereasunknown and nonwords will lead to more phonological processing because of a lack of already storedorthographical information in lexical memory. This specific characteristic raises the question for thepresent study how children interact with different word material in matters of their strategic behavior.

1.3. Aim of the study

The aim of this study is to test the three assumptions of the Overlapping Waves Model in Germansingle-word reading by using a set of common and uncommonwords and word-similar and -dissimilarpseudowords during a microgenetic analysis (Siegler, 2006) with 2nd and 4th graders. The goal ofa microgenetic analysis is direct observation of the process of change that occurs in learning andcognitive development. Inmicrogenetic studies, individuals are typically engaged in the same problem-solving task over repeated occasions in order tomeasure intra-individual variability. In our studyweusethe term “microgenetic” for a single task trial-by-trail procedure to assess within-child variability. Thisapproach enables us to analyze children’s strategy behavior related to specific word material acrossdifferent age groups and leads to the following general research questions: (1) Do children in grades 2and 4 apply diverse and different strategies (retrieval and backup strategies) within and betweendifferent word groups? (2) Do children use their repertoire of strategies in an adaptive way acrossspecific word material? (3) Is there an age-related change in children’s reading-strategy behavior?

1.3.1. Reading strategiesAsa complexprocess reading implies awide rangeof activities that are involved in the recognitionand

processing of words. Strategies in reading development are described in several ways and differenttheoretical frameworks (Coltheart et al., 1993; Frith, 1985; Marsh et al., 1981). During the acquisition of

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reading skills, children apply different strategies, for example: phonological strategies– letters and sounds(graphemesandphonemes) are interconnectedandmanipulated to access aword’smeaning (Farrington-Flint et al., 2008; Farrington-Flint &Wood, 2007; Stuart & Coltheart,1988); orthographic strategies – usinganalogies from familiar words to ascertain the pronunciation of an unfamiliar word (Farrington-Flint &Wood, 2007; Goswami, 1993a); retrieval strategy – direct recall of a word from the lexical memory dueto visual recognition with or without phonological decoding (Share & Stanovich, 1995); combined strat-egies – retrieval of word parts frommemory in addition to reading letter by letter or using analogies forother word parts (Ehri, 1998; Ehri & Robbins, 1992). Research demonstrated that children use variablestrategies adaptivelyandgradually up to thepointof automated reading (Ehri,1995,1998, 2005),which inturn may be described as a continuous retrieval process. Interestingly, the findings of these studiesshowed that children’s strategybehaviorfits to theassumptionsof theOverlappingWavesModel in termsof the parallel occurrence and alternate frequency of different reading strategies. Children use differentstrategies during their complete reading development and rely on the coexistence of their strategyrepertoire. Even adultswhose automated reading skills are perfectly developed still usebackup strategiessuch as sounding out word parts when they are confronted with unknownword material.

1.3.2. Variations in reading demandsFor an adequate analysis of elementary school children’s single word reading in the context of the

OverlappingWavesModel, the selection of the presentedwordmaterial is very important. In this studywe trigger children’s strategy behavior by usingwordmaterial with specific demands: commonwords –very easy and familiar words that are likely to be retrieved from memory by most of the children;uncommon words - existing words but very unfamiliar for elementary school children; word-similarpseudowords – nonexistent self-created words that resemble real words in sound and structure; word-dissimilar pseudowords - nonexistent self-createdwords with no resemblance to real words in sound orstructure. Moreover, the word materiel is subdivided into two and four-syllable words in each group toexamine the influence of word length. For an adequate analysis of age-related differences as an indi-cator for development in children’s strategic behavior we compared 2nd and 4th graders. The selectionof the word material and its variations are based on the following considerations: (1) The extent offamiliarity with aword determines the probability of fast and accurate recognition of the word in othercontexts (Miller, 2000). (2) Unfamiliar words contain partly familiar units from already known wordsand analogies in terms of semantic content are possible (Klicpera & Gasteiger-Klicpera, 1994). (3)Word-similar and dissimilar pseudowords have no semantic meaning but vary in regard to possibleuseful characteristics for backup reading strategies (Klicpera, Gasteiger-Klicpera, & Schabmann, 1993).(4)When presentedwith highly frequent words, younger children’s reading performance appears to becomparable to that of older and more skilled readers. However, younger children are considerablyslower and make more errors with longer and less familiar words and with pseudowords (Backman,Mamen, & Ferguson, 1984; Baddeley, Ellis, Miles, & Lewis, 1982).

The main goal of the present study was to examine whether the three key features proposed by theoverlappingwavesmodeldwidespreadvariability, adaptivechoice, andage-relatedchanged canbe foundin reading. More specifically, we were interested in how children interact with different word material inregard to their strategic behavior. The microgenetic analysis of strategies allowed us to identify whichstrategies the 2nd and 4th graders would exhibit and how effectively and adaptively they would use them.Weassume thatbothgroupsof childrenwoulduse retrieval andavarietyof backup strategies dependingonthe different word groups, that retrieval andmore elaborated strategies would be more effective, and thatchildren choose adaptively among their repertoire of strategies. Finally, we hypothesize that a betterperformanceof4thgraders results frombetter,moreelaboratedstrategies, that theywouldshowgreateruseof more effective strategies, and would make skilled adaptive choices among the strategies.

2. Method

2.1. Participants

Thirty 2nd grade (10 male and 20 female) and twenty-eight 4th grade (9 male and 19 female)students were recruited from German elementary schools. The mean age of the 2nd graders was 8;4

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years and of the 4th graders 10;2 years. The students’ reading achievement was measured by theeconomic German reading aptitude test WLLP (Würzburger Leise Leseprobe; Küspert & Schneider,1998) and was within the normal range (percentile rank M ¼ 68.60, SD ¼ 22.79 for 2nd grade andpercentile rankM¼ 71.07, SD¼ 21.85 for 4th grade). General intelligence of the students was measuredby the SPM (Raven Standard Progressive Matrices; Raven, Court, & Raven,1979) and revealed also to bewithin the normal range (IQ M ¼ 110.62, SD ¼ 16.97 for 2nd grade and M ¼ 100.25, SD ¼ 10.98 for 4th

grade). A full parental consent was obtained for each child’s participation in the study.

2.2. Materials

Each child was presented a total of 32word cards subdivided into fourword categories: (1) commonwords (taken from early school reading books) e.g. Katze (cat), (2) uncommon words (taken fromsecondary school books glossary) e.g. Mangold (chard), (3) word-similar pseudowords e.g. Mulpen, (4)word-dissimilar pseudowords e.g. Nostur. The words within each word category differed in terms ofword length, resulting in 4 two- and 4 four-syllable words each. All words were carefully controlled byspecific phonological and morphological characteristics: Word onsets – consonant-cluster at a begin-ning of a word appear to be harder to read than single consonants (Treiman & Zukowski, 1996).Therefore, all words start with a single consonant or with a phoneme. Word complexity - consonant-cluster with more than two consonants demand a more complex processing and articulation of wordsand pseudowords (Gathercole, Willis, Emslie, & Baddeley,1991). As a result we selected only words andpseudowords with at least one consonant-cluster with two consonants and we avoided complexconsonant clusters with more than two consonants. Generally, mutated vowels were not included inthe material to assure readability and comparability of words and pseudowords. All words are listed inthe appendix.

2.3. Procedure

Participating children were tested individually in a separate room in their schools according tomigrogenetic trial-by-trial procedure during which a task related question is asked after each item(Miller, 2000; Siegler, 2006). At the beginning of a session, children were presented with theinstructions and with an example word of all word categories to practise the test procedure. Theinstruction based on the original instructions used in several studies by Siegler (e.g. Rittle-johnson &Siegler, 1999; Siegler, 1988). After the children read a word they were asked “How did you read thisword.?”. When a child repeatedly remained quiet or said ”I don’t know”, he or shewas asked “Did youjust know how to read it? Or did you recognize a part of the word? Have you used any rule? Or did youdo something else?” All sessions were videotaped to record children’s self-report and their overtstrategy behavior.

2.4. Strategy coding

Two independent coders classified each children’s videotaped overt and self-reported strategies forall videotapes in a subsequent analysis. Strategies were coded according to the following rules: (1)corresponding observed behavior and self-report regarding retrieval - coded as retrieval, (2) corre-sponding observed behavior and self-report regarding backup strategies – coded as backup, (3)observed backup strategies and reported retrieval – coded as backup, (4) no observable strategicbehavior and reported backup – coded as backup. The classification rules came into effect as follows:rule 1 was applied on 24% and 30%, rule 2 on 53% and 32%, rule 3 on 15% and 19%, and rule 4 on 8% and19% of trials for 2nd graders and 4th graders, respectively. That is, in only les then 1/5 of the cases,children were not aware or not able to verbalize what they had done to read the words (rule 3).However, correspondence of observable and reported behavior was rather high (rules 1 and 2) andcomparable to the findings by Rittle-Johnson and Siegler regarding strategies on spelling. Moreover,both coders also rated reading accuracy. The assessment of the strategies and accuracy was highlyreliable: the independent coders agreed in 89% of the ratings. Finally, the few disagreements wereresolved through the comparison of the ratings and a concluding discussion.

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3. Results

Unless otherwise noted, all reported statistical comparisons are significant at the p < .05 level.

3.1. Strategy identification and classification

Eight categories of strategies could be identified on the basis of the video- and self-report codingdata (in parentheses you will find the percentages of usage within 2nd and 4th grade children,respectively): (1) direct retrieval (26%, 34%), (2) identification of word parts (6%, 4%), (3) identificationof morphological units (0%, 0%), (4) use of analogies for word parts (14%, 13%), (5) use of analogies fortheword (12%,15%), (6) syllable reading (13%, 3%), (7) letter by letter reading (29%, 30%), (8) unspecifiedstrategy (1%, 1%).For a more economic analysis of strategy behavior a simplification of the categoriesseemed to be appropriate. As a result, we generated four higher level categories that summarize theaforementioned strategies: retrieval - strategy 1; elaborated backup – strategies 2–5 which includepartial retrieval; moderate elaborated backup – strategies 6 and 7 which are based on synthetical andsequential reading without retrieval; non-specific backup – strategy 8.

3.2. Variability of strategy use

Regarding our first research question “Do children in 2nd and 4th grade apply diverse and differentstrategies within and between different word groups?” we took a closer look at the strategyfrequencies in the different age groups. In 2nd grade none of the children used only one strategy.Instead, here, 3% (one child) used two strategies, 40% used three strategies, and 57% used four strategiesover the 32 trials. None of the 4th grade children used only one or even two strategies. Here, 71% usedthree strategies, and 29% used 4 strategies over the 32 trials. As expected, the choice of the (pseudo-)word material prompted the children to vary in their strategic behavior. Table 1 shows the means ofpercentages of strategy use for children in 2nd and 4th grade as a function of the different word groups.Evidently, children in both grades used different and multiple strategies and the applied strategybehavior differ among the variedword groups. Overall, 4th graders usedmore retrieval in the real-wordgroups and more elaborated backup in the made-up word groups. In contrast, the 2nd graders used

Table 1Means (and standard deviations) of percentages strategy usage as a function of word group, grade, and strategy.

Strategy

Retrieval Elaboratedbackup

Moderate elaboratedbackup

Non-specificbackup

Word-group grade 2Common words s. (WG1) 94 (13) – 3 (9) 3 (10)Common words l. (WG2) 72 (26) 16 (21) 5 (14) 7 (13)Uncommon words s. (WG3) 7 (13) 51 (25) 40 (31) 2 (8)Uncommon words l. (WG4) 7 (11) 47 (29) 42 (25) 4 (10)Word-similar pseudowords s. (WG5) 4 (19) 62 (32) 33 (31) 1 (5)Word-similar pseudowords l. (WG6) 1 (5) 38 (35) 60 (33) 1 (5)Word-dissimilar pseudowords s. (WG7) 3 (14) 43 (30) 50 (28) 4 (9)Word-dissimilar pseudowords l. (WG8) – 32 (31) 68 (31) –

Word-group grade 4Common words s. (WG1) 100 – – –

Common words l. (WG2) 90 (17) 8 (15) 2 (7) –

Uncommon words s. (WG3) 15 (20) 48 (30) 35 (23) 2 (7)Uncommon words l. (WG4) 18 (18) 57 (29) 21 (28) 4 (10)Word-similar pseudowords s. (WG5) 3 (11) 70 (25) 26 (25) 1 (5)Word-similar pseudowords l. (WG6) 2 (7) 53 (33) 45 (35) –

Word-dissimilar pseudowords s. (WG7) 4 (12) 57 (25) 38 (28) 1 (5)Word-dissimilar pseudowords l. (WG8) 1 (5) 39 (30) 58 (29) 2 (7)

Note: short words (s.), long words (l.)

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more moderately elaborated backup in both the real-word groups and in the made-up word groups.The usage of non-specific backup was very infrequent in both age groups.

3.2.1. Strategy useFor a statistical analysis of the frequency of applied strategies we conducted a 2 (grade) � 8 (word

group)� 4 (strategy type) repeated measures analysis of variance (ANOVA). Because this ANOVA treatsipsative measures on the first three factors, the degrees of freedom are adjusted by Box’s epsilon tocontrol Type I error rates (Greer & Dunlap, 1997). No main effects for word groups and no main effectregarding the grade level can be reported because children always showed strategy behavior in eachword group and in both grades. The analysis revealed a significant main effect of strategy type, F(1.32,79.68) ¼ 79.37, p < .001. This main effect was qualified by significant two-way interactions betweenstrategy type and grade, F(1.32, 73.68) ¼ 4.12, p < .05, eta2 ¼ 0.06 and word group and strategy type,F(8.23, 460.64) ¼ 122.52, p < .001, eta2 ¼ 0.69. In addition, the three–way interaction among wordgroup, strategy type and grade, F(8.23, 460.64) ¼ 1.88, p < .05, eta2 ¼ 0.32, was also significant. Fig. 1pictures the strategy usage of 2nd and 4th graders across the eight word groups. Bonferroni post-hoccomparisons were conducted to detect strategy-specific differences between 2nd and 4th graders.When reading commonwords (WG1 andWG2) 4th graders used significantly more retrieval than 2ndgraders. In both age groups, however, this strategy turned out to be the predominant reading strategyon common words. In addition, 4th graders used significantly more retrieval for the remaining realwords (WG3 and WG4) than 2nd graders. For common words l. (WG4) we found that 2nd graders usedsignificantly more moderate elaborated backup than the 4th graders. No further strategy-relateddifferences were found for the comparison of strategy frequency between 2nd and 4th grade students.

In order to examine children’s strategy use in more detail, we focused on the differences in theapplied strategies within 2nd and 4th graders. Children in 2nd grade used retrieval when readingcommonwords (WG1 andWG2) significantly as the most prevalent strategy (see Fig. 1). When readinguncommon words (WG3 and WG4) they relied basically on elaborated and moderate elaboratedbackup, whereas these strategy types differed not significantly from each other. The same pattern ofresults was found for the remaining word groups with two exceptions: 2nd graders read word-similarpseudowords s. (WG5) by using significantly more often elaborated backup and word-dissimilarpseudowords l. (WG8) by using significantly more often moderate elaborated backup. Children in 4th

grade also exhibit retrieval significantly more often than all other strategy types when readingcommon words (WG1and WG2). As can be seen in Fig. 1, 4th graders consistently applied elaboratedbackup when reading the words of the remaining word groups. We should mention that only foruncommon words l. (WG4) and for word-similar pseudowords s. the elaborated backup strategy wassignificantly more frequently used than moderate elaborated backup. This means that in the othercases the usage of moderate elaborated and elaborated backup was comparable.

3.3. Adaptive strategy use and age-differences

The second and third research questions “Do children use their repertoire of strategies in an adaptiveway across specific word material?” and “Is there a gradual change in children’s reading strategybehavior over time?” demanded further analyses of the strategy behavior. Table 2 displays themeans ofpercentages of words that were read correctly by 2nd and 4th graders across the different word groups(WG). We found that children, both in 2nd and 4th grade, made relatively few mistakes: percentages ofcorrect answers in 2nd grade:WG1, Commonwords short (s.)¼ 99;WG2, Commonwords long (l.)¼ 89;WG3, Uncommon words s. ¼ 63; WG4, Uncommon words l. ¼ 63; WG5, Word-similar pseudowordss. ¼ 67; WG6, Word-similar pseudowords l. ¼ 77; WG7, Word-dissimilar pseudowords s. ¼ 85; WG8,Word-dissimilar pseudowords l.¼63. Percentagesof correct answers in4th grade:WG1, Commonwordsshort (s.)¼ 100,WG2, Commonwords long (l.)¼ 95,WG3, Uncommonwords s.¼ 85,WG4, Uncommonwords l.¼ 71,WG5,Word-similar pseudowords s.¼ 88, WG6,Word-similar pseudowords l.¼ 80,WG7,Word-dissimilar pseudowords s. ¼ 88, WG8, Word-dissimilar pseudowords l. ¼ 74.

It is noticeable that children in both grades could easily apply retrieval when reading commonwords s. (WG1). Children in 2nd grade used less retrieval during common word l. reading than the 4th

graders. With the exception of short word-similar pseudowords (WG5), 2nd graders relied mostly on

a

b

Fig. 1. a. Percentages of usage of retrieval, elaborated backup (elab. backup), moderate elaborated backup (mod. elab. backup), andunspecific backup (unspec. backup) as a function of word group (Common words short ¼ WG1, Common words long ¼ WG2,Uncommon words short ¼ WG3, Uncommon words long ¼ WG4, Word-similar pseudowords short ¼ WG5, Word-similar pseu-dowords long ¼ WG6, Word-dissimilar pseudowords short ¼ WG7, and Word-dissimilar pseudowords long ¼ WG8) for 2nd grade, b.Percentages of usage of retrieval, elaborated backup (elab. backup), moderate elaborated backup (mod. elab. backup), and unspecificbackup (unspec. backup) as a function of word group (Commonwords short ¼WG1, Commonwords long ¼WG2, Uncommonwordsshort ¼ WG3, Uncommon words long ¼ WG4, Word-similar pseudowords short ¼ WG5, Word-similar pseudowords long ¼ WG6,Word-dissimilar pseudowords short ¼ WG7, and Word-dissimilar pseudowords long ¼ WG8) for 4th grade.

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Table 2Means (and standard deviations) of percentages words read correctly as a function of word group, grade, and strategy.

Strategy

Retrieval Elaboratedbackup

Moderate elaboratedbackup

Non-specificbackup

Word-group grade 2Common words s. (WG1) 93 (25) – 3 (18) 3 (16)Common words l. (WG2) 69 (46) 12 (32) 3 (18) 5 (22)Uncommon words s. (WG3) 7 (26) 22 (42) 33 (47) 2 (9)Uncommon words l. (WG4) 6 (24) 27 (44) 28 (45) 3(16)Word-similar pseudowords s. (WG5) 3 (16) 40 (49) 23 (42) 1 (9)Word-similar pseudowords l. (WG6) – 28 (45) 48 (50) 1 (9)Word-dissimilar pseudowords s. (WG7) 3 (16) 33 (47) 45 (50) 4 (20)Word-dissimilar pseudowords l. (WG8) – 18 (39) 45 (50) –

Word-group grade 4Common words s. (WG1) 100 – – –

Common words l. (WG2) 88 (33) 5 (23) 2 (13) –

Uncommon words s. (WG3) 15 (36) 28 (45) 28 (45) 4 (21)Uncommon words l. (WG4) 18 (38) 37 (48) 13 (34) 4 (19)Word-similar pseudowords s. (WG5) 3 (16) 58 (50) 26 (44) 1 (9)Word-similar pseudowords l. (WG6) 2 (13) 46 (50) 32 (47) –

Word-dissimilar pseudowords s. (WG7) 4 (21) 53 (50) 29 (46) 1 (9)Word-dissimilar pseudowords l. (WG8) 1 (9) 28 (45) 44 (50) 2 (13)

Note: short words (s.), long words (l.)

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moderate elaborated strategies when reading the words of the remaining more complex word groups(WG3, WG4, WG6, WG7 and WG8). In contrast, 4th graders showed a comparable usage of retrievalwhen reading commonwords l. (WG2) and they essentially relied on elaborated backup when readingwords from the remaining word groups (WG3 to WG7; with the exception of more moderate elabo-rated backup use in the case of Word-dissimilar pseudowords l. WG8). Generally, non-specific backupwas very infrequently used by both groups of participants.

3.3.1. Strategy effectivenessFor the statistical analysis of the strategies’ effectiveness we contrasted retrieval and the combined

backup strategies. The reason to merge the three backup-strategy categories was that by contrastingthose two groups we can differentiate between automatized and cognitively controlled procedures(Rittle-johnson & Siegler, 1999). We again conducted a 2 (grade) � 8 (word group) � 2 (retrieval vs.backup strategy) repeated measures analysis of variance (ANOVA). We found significant main effectsfor word group, F(4.74, 32.88) ¼ 11.14, p < .001, eta2 ¼ 0.17, strategy type, F(1.00, 56.00) ¼ 73.57,p < .001, eta2 ¼ 0.57, and grade, F(1,56) ¼ 6.23, P < .05, eta2 ¼ 0.10. Moreover, the two-way interactionsbetween word group and grade, F(4.75, 265.92) ¼ 5.86, p < .001, eta2 ¼ 0.09 and word group andstrategy type, F(4.75, 265.92) ¼ 161.82, p < .001, eta2 ¼ 0.73, were found to be significant. In addition,the three-way interaction among word group, strategy type, and grade, F(4.75, 265.92) ¼ 2.57, p < .05,eta2 ¼ 0.04, was also found to be significant. Bonferroni post-hoc comparisons were conducted to testdifferences in strategy effectiveness between 2nd and 4th graders in more detail. Children in 2nd gradeused backup strategies more effectively when reading common words (WG1 and WG2) than 4th

graders. This result might be an artifact, because backup was not used by the older children in theseword groups. Children in 4th grade, however, used retrieval significantly more effectively whenreading uncommonwords (WG3 andWG4). In addition, effective retrieval usewas comparable for bothage groups during reading of short word-similar pseudowords (WG5). Within the same word group(WG5) however, 4th graders backup usage turned out to be significantly more effective than that of 2nd

graders. For all remaining word groups no significant age-differences were found.Further comparisons were conducted to reveal differences between effective strategy use within

2nd and 4th grade, respectively. Children in 2nd grade used retrieval significantly more effectively thanbackup when reading common words (WG1 and WG2). However, all other word groups were readmore effectively when they implemented the backup strategies. Children in 4th grade also used

S. Lindberg et al. / Journal of Neurolinguistics 24 (2011) 556–570566

retrieval significantly more effectively when reading common words, but also when they readuncommonwords (WG3 andWG4), retrieval tended to be more effective than backup (WG3) or was atleast equally effective as backup (WG4). In the remaining word groups the use of backup was signif-icantly more effective than retrieval.

4. Discussion

In this study we examined the three assumptions of Siegler’s Overlapping Waves Model d wide-spread variability, adaptive choice, and age-related change d by presenting German 2nd and 4th gradeelementaryschool childrena single-wordreading task. The fewprevious studiesonvariability in readingstrategies focusedmainly on the target status of competent reading, namely retrieval, and attached lessimportance to theother strategies, namelybackupstrategies (e.g., Farrington-Flint et al., 2008).Hence, inthe present study one of our main goals was to highlight the usage of the whole repertoire of readingstrategies. To evoke the usage of several distinct strategies, we used different types of common anduncommon words and word-similar and word-dissimilar pseudowords. In addition, we contrastedreading-strategy usage of early readers and more advanced readers to track the developmental path inreading achievement. In this concern, we discuss the results according to our research questions.Regarding our first research question, children in 2nd and 4th grade actually exhibited a broad repertoireof diverse reading strategies and also applied multiple strategies within and between the presentedword groups across the 32 trials. Accordingly, the application of varied word material indeed seems toinduce a more comprehensive strategy usage at both grade levels. Regarding our second researchquestion, wewere able to demonstrate that children in 2nd and 4th gradewere perfectly able to use theirrepertoire of strategies in an adaptiveway. For instance, childrenof both agegroups read commonwordsby direct retrieval whereas they read uncommon words more often by using backup strategies. More-over, our analysis revealed that children adapted to the demands of the respective word material byusing more elaborated strategies when reading less complex words and by using less elaboratedstrategies when reading more complex words. In addition, the effectiveness of retrieval and backupvaried also with the characteristics of the word material. Regarding our third research question, ourfindings clearly showed age-related differences in strategy usage. Children in 4th grade outperformed2nd graders by using more elaborated strategies in almost all word groups. Only common words weremainly read using direct retrieval by both age groups. Moreover, 4th grade children even used retrievaleffectively when reading uncommonwords, whereas children in the 2nd grade only regarded backup asan effective reading approach for this word group. In conclusion, the findings of our study showed thattheobserved strategyof elementary school childrenconfirms theassumptionsof theOverlappingWavesModel in terms of the parallel occurrence and alternate frequency of different reading strategies, theadaptive use of strategies and the general improvement in strategy choice by older children.

Complementary to the findings of Farrington-Flint et al. (2008), our study further highlights thetransferability of the Overlapping Waves Model to reading. With respect to traditional stage models(Frith, 1985; Marsh et al., 1981), the results of these studies demonstrate that the assumption ofa stepwise development is not applicable to reading development. Even if a continuous progress ofstrategy usage is observable in reading development, this progress occurs in a more complex andvariable way than described by distinct succeeding steps (e.g., Goswami, 1993b; Ehri, 2005). Retrievinga word directly from memory still seems to be the most effective and fastest and therefore mostcompetent strategy for reading when one has already automated the processing of a word. However,children continue to use alternative strategies when confronted with very complex or unknown wordmaterials (Siegler & Jenkins, 1989). In our study we demonstrated that children exhibit strategies ofdifferent quality at the beginning and at the end of elementary school. Hence, strategy use in readingdevelopment seems to be simultaneous rather than unidirectional. When reading a specific word,retrieval as well as further elaborated or non-elaborated strategies can be applied at one time and overtime in multiple ways.

One of the most important characteristics in reading-strategy development, however, is that chil-dren make highly adaptive choices among the usage of retrieval or backup strategies. This is also in linewith the findings of Farrington-Flint et al. (2008) who reported that retrieval was mostly exhibitedwhen five to seven year old children were presented high frequency items and short items, assuming

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that these children had already stored these words in their lexical memory (Share, 1999). Thisprocedure can be seen as a very adaptive approach because faster retrieval strategies can be used onproblems where correct answers are expected and slower backup strategies can be applied on prob-lems where accurate performance is not guaranteed by direct memory retrieval (Lemaire & Siegler,1995; Siegler, 1988). One of the best ways of analyzing the phenomenon of adaptive strategy choiceis to vary the difficulty of the problems that are to be solved or, as in our study, to vary the wordmaterials to be read. In order to identify adaptive strategy choice, we presented four variations of realwords (short and long common words and short and long uncommon words) and four variations ofself-created words (short and long word-similar pseudowords and short and long word-dissimilarpseudowords) thus offering reading tasks with gradually increasing difficulty. Comparable to theresults in the study by Farrington-Flint et al. (2008), our children in 2nd and 4th grade relied almostsolely on retrieval when reading common words. The reading of uncommon words already demon-strated a general shift from retrieval to alternative backup strategies. The older children, however, stillapplied some retrieval and also more elaborated backup than the younger children, who mainly reliedon moderate and elaborated backup. Moreover, the aforementioned tendency was valid also for theremaining word groups. With increasing word difficulty or complexity, children in both grades wereforced to choose among their repertoire of backup strategies. Thereby, children in 4th grade reliedmoreoften on elaborated backup, whereas 2nd graders mostly implementedmoderate backup. Nevertheless,other strategies were still prevalent across all word groups and in both age groups. In sum, we wereable to demonstrate that in single-word reading the frequency of the use of backup strategies isa function of the level of difficulty of the words to be read.

The described results are encouraging to speculate on the underlying factors of backup strategies. Incorrespondence to the findings of other studies we demonstrated that uncommon words and word-similar pseudowords can produce more elaborated backup in children’s reading. Given that theorthographic characteristics of those words are comparable to already knownwords, strategies such asrecall of word-subunits and letter sounds from memory (Share, 1999) and the usage of analogies fromother words (Ehri, 1999) might have been stimulated. Word-dissimilar pseudowords are expected toinduce strategy alternatives to retrieval, because it is not possible to recall those words or word-subunits directly frommemory. Whereas word-similar pseudowords share some characteristics of realwords, word-dissimilar pseudowords provide less information on real word-basis. Therefore, it is morelikely that less elaborate backupwill be used. According to this, findings revealed that younger and lessadvanced readers rely more on sequential/synthetic reading by using the phonological information ofthe displayed graphemes rather than retrieving word-subunits, what could be considered as a moreelaborated backup strategy (Harm, MacCandliss, & Seidenberg, 2003). Generally, it is assumed thatthese phonological recoding strategies are essential for children to build up their word knowledge basein lexical memory (Ehri, 1995; Share, 1999). A more developed vocabulary or word knowledge base isimportant for direct retrieval but also for drawing analogies between word-subunits and whole words(Ehri, 1995, 1998; Ehri & Robbins, 1992). Thus, advanced readers and older elementary school childrenshould be able to use their more developed vocabulary not only for direct retrieval but also forproducing more elaborated strategies (that includes partial retrieval for word-subunits or recall ofalternative words that can be used for analogies). Due to the usage of different word material readingstrategy behavior can be classified according to the four phases of the mediated phase model (Ehri,1995) and also to the orthographic and phonological processes of the self-teachingmodel (Share,1995).

In contrast to our findings, Farrington-Flint et al. (2009) reported a limited amount of variability in5–7 year old children’s strategy use in reading and spelling tasks (mostly retrieval and phonologicalbackup). Backup such as drawing analogies or usage of morphological rules were not applied in greatextent, so that the authors suggested that these strategies were relatively uncommon to young chil-dren. The findings of our study, however, demonstrate that the use of different wordmaterial results ina greater variability of strategies in elementary school children and could yield to distinguishabledifferences between 2nd and 4th graders. Therefore, our approach can be considered as an extension ofthe recent studies of Farrington-Flint et al. (2008; 2009) on reading strategies, with our studycompleting the picture by analyzing children’s backup strategy usage in more detail.

Recent research in the developmental neurosciences underlines that the brain is flexible and dynamicduring the acquisition and improvement of reading (for review, see Schlaggar & Mccandliss, 2007).

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Interestingly, it seems that there is not one distinct representation for the development of skilled readingbut rather a simultaneously and alternating increase anddecrease in reading related brain regions (Brownet al., 2005). An increase in neuronal activity, for example, could be found in lateral frontal and parietalcortical regions over age, what seems to be interrelated with a more controlled, efficient reading anda greater awareness of language structure (e.g., Corbetta & Shulman, 2002; Dosenbach et al., 2006).Decreases canbe found inactivity inposterior regionsof thebrain inparticular in the left temporal-parietalcortex. A change in activity in this region seems to be related to phonological processing that serves asa foundation for the development of the lexical memory that is interrelated with orthographical pro-cessing representedbyactivity in the left ventraloccipital-temporal cortex.Over time,direct retrieval frommemory becomes more efficient and phonological processing declines when reading common and highfrequent words (Church, Coalson, Lugar, Petersen, & Schlaggar, 2008; Pugh et al., 2001). In regard to ourfindings it is to mention, that skilled readers showed stronger activation in the left temporal-parietalregionwhen reading low frequencywords and pronounceable pseudowords compared to their readingofhigh frequent common words (Schlaggar & Church, 2009). This means that, even if phonological pro-cessing is no longer regularly involved in skilled reading the brain remains flexible and can fall back onprocessing activities when challenged with less experienced tasks. Future research could utilize theframework of the OverlappingWaves Model in combinationwith neuroscience methods to examine thevariable, adaptive and the gradual change of strategies during reading development in more detail.Correlates between brain activity and the use of different strategies cluster, such as elaborated and lesselaborated strategies, may be beneficial for a better understanding of reading development in general. Inthis regard, recentfindings in the arithmetic domainare verypromising inhighlighting the applicabilityofneuroscientific methods to the assessment of different strategy behaviors. For instance, functionalmagnetic resonance imaging (fMRI) studies showed that simple arithmetic tasks,whose results can easilyretrieved from memory, evoke stronger activation in left-hemispheric language regions, including thesupramarginal and angular gyri (Campbell &Xue, 2001).More difficult tasks, however,which demand theusage of procedural strategies, were related to stronger bilateral activation in frontal and parietal cortices(Dehaene, Piazza, Pinel, & Cohen, 2003; Grabner et al., 2007, 2009; Stanescu-Cosson et al., 2000).Furthermore, results of event-related potential (ERP) studies showed also different activation patterns forretrieval and procedural strategies in calculation tasks (Jost, Beinhoff, Hennighausen, & Rosler, 2004;Nunez-Pena, Cortinas, & Escera, 2006). In addition, De Smedt, Grabner, and Studer (2009) analyzedevent-related synchronization (ERS) and desynchronization (ERD) in the theta and alpha bands duringcalculation, which represent a high occurrence of retrieval or procedural strategy use, respectively. Theresults showed thatarithmetic fact retrieval is reflected in left-hemisphericERS in the thetaband,whereasprocedural strategies are characterized by bilateral parieto-occipital ERD in the alpha band. Therefore,both fMRI and EEGmeasures seem to be apt to identify specific strategy usage. Results of the specificity ofstrategy-related effects in arithmetic seem to be very encouraging andmay inspire comparable studies inthe domain of reading.

Future studies could be realized in a longitudinal setting to assure the assumption of gradualchange, which is in our study only reflected by a cross-sectional comparison of 2nd and 4th graders.Beyond the focus on typically developed readers, a consideration of skilled and reading impairedchildren would be appropriate to achieve more information about possible applications of the Over-lapping Waves Model. The use of microgenetic analyses could give deeper insights in the readingapproach of skilled and impaired readers. Possible shortcomings in reading strategies, such as theinefficient use of strategies or the failure of direct retrieval, could be uncovered.

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