The role of executive functions in bilingual ... - Wiley Online Library

Scandinavian Journal of Psychology, 2015, 56, 297–305

DOI: 10.1111/sjop.12198

Health and Disability The role of executive functions in bilingual children with reading difficulties NILOUFAR JALALI-MOGHADAM and REZA KORMI-NOURI € Center for Health and Medical Psychology (CHAMP), Orebro University, Sweden

Jalali-Moghadam, N. & Kormi-Nouri, R. (2015). The role of executive functions in bilingual children with reading difficulties. Scandinavian Journal of Psychology, 56, 297–305. To explore the joint effect of reading difficulties (RD) and bilingualism on executive functions, 190 children of four groups of 9–12 year-olds (41 bilinguals with RD, 45 monolinguals with RD, 45 bilinguals without RD, and 59 monolinguals without RD) were examined on the Concentration game, Tower of Hanoi, and Stroop as measures of executive functioning tapping into inhibitory/attentional control, working memory and planning ability. The most prominent finding was that in terms of RD, the speed of performances decreased dramatically. This general decrease was more pronounced for bilingual children with RD than for their monolingual counterparts. In conclusion, the findings suggest that while bilinguals gain more from executive functions in normal reading, they lose in terms of RD. Such an outcome confirms that executive functions are essential components of both reading and bilingualism, which depending on whether reading conditions are normal or difficult will produce cognitive advantages or disadvantages. Further, it is argued that dissimilarity between the Farsi and Swedish languages may complicate handling of such a situation. Key words: Executive functions, bilingual children, reading difficulties. € € Niloufar Jalali-Moghadam, CHAMP (Center for Health & Medical Psychology), Orebro University, 701 82 Orebro, Sweden. Tel: 0046-19-303629; fax: 0046-19-303484; e-mail: [email protected]

INTRODUCTION Reports of the effects of bilingualism on diverse cognitive areas have been neither thoroughly positive nor entirely negative. The countervailing patterns of outcomes readily bring the idea of dissociation to mind. Conspicuously, two major hypothetical lines exist that largely contrast with each other regarding the cognitive benefits and costs of bilingualism. Extensive research evidence supports the superiority of bilinguals on non-verbal tasks that tap into executive functions (EF) such as inhibitory control/conflict resolution (e.g., Bialystok, Craik, Klein & Viswanathan, 2004; Colzato, Bajo, van den Wildenberg et al., 2008; Salvatierra & Rosselli, 2011). Luo, Fergus, Moreno and Bialystok (2013, p. 28) proposed that there seems to be “a general enhancement of EF associated with bilingualism”. This bilingual advantage has been shown using several tasks such as the Stroop (e.g., Hernandez, Costa, Fuentes, Vivas & Sebastian-Galles, 2010), Simon (e.g., Martin-Rhee & Bialystok, 2008), card-sorting (e.g., Bialystok & Martin, 2004) and attention network tasks (e.g., Costa, Hernandez & Sebastian-Galles, 2008). Furthermore, bilinguals have been shown to underperform relative to monolinguals (e.g., Bialystok, Luk, Peets & Yang, 2010; Ivanova & Costa, 2008) on estimates of language processing, lexical retrievals and receptive vocabulary store such as the picture naming task (e.g., Gollan, Montoya, Fennema-Notestine & Morris, 2005), the Boston Naming Test (e.g., Roberts, Garcia, Desrochers & Hernandez, 2002) or tip-of-the-tongue measures (e.g., Gollan & Acenas, 2004). Several factors likely affect these different outcome performances including the level of correspondence between languages. For example, bilinguals might benefit from similarity between languages. Bialystok, Majumder and Martin (2003) implied that the similarity between Spanish and English was © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd

advantageous to Spanish-English bilinguals compared with Chinese-English bilinguals with regard to reading tasks. Kormi-Nouri, Jalali-Moghadam and Moradi (forthcoming) found a bilingual advantage for similar languages (Farsi and Kurdish), whereas a bilingual disadvantage was more pronounced for less similar languages (Farsi and Turkish). However, the global bilingual advantage (especially with regard to EF) does not persist among those with certain impairments or disorders e.g., ADHD (e.g., Boonstra, Oosterlaan, Sergeant & Buitelaar, 2005). In the Mor, Yitzhaki-Amsalem and Prior (2014) study, the lowest outcome performances for EF were observed among bilinguals with ADHD relative to monolinguals with or without ADHD and bilinguals without ADHD. These authors concluded that the combined effect of bilingualism and ADHD cannot improve EF deficits. To our knowledge, no study has specifically studied the interaction of bilingualism and reading difficulties (RD) with regard to EF. EF, used as an umbrella term, arguably includes three pivotal sub-components: inhibitory control, working memory (WM) and cognitive flexibility (Diamond, 2013). Bilinguals’ overall superiority with regard to inhibiting incoherent information has been well documented because they continually make efforts to accommodate relevant information and ignore the fronting language (Bialystok, 2001). Inhibition is reciprocally linked to WM; this ability is concerned not only with retention but also the manipulation of information (Baddeley, 2000). Engle, Tuholski, Laughlin and Conway (1999) postulated that WM accounts for the contemporaneous accompaniment of short-term memory and controlled attention, indicating that WM and inhibitory control cooperate with each other. Whether WM is enhanced among bilinguals remains unclear. Indeed, significant differences do not usually exist between the performances of bilinguals and

298 N. Jalali-Moghadam and R. Kormi-Nouri monolinguals (e.g., Bonifacci, Giombini, Bellocchi & Contento, 2011). However, Morales, Calvo and Bialystok (2012) concluded that an advantage in WM is clearly expected when the task requires a greater level of dependency on EF. Along the same lines, Luo et al. (2013) showed that bilingualism provided an advantage with regard to spatial rather than verbal WM. They attributed this finding to the bilingual disadvantage shown on verbal tasks compared with the advantage/competency shown on control tasks. In addition, bilinguals are generally superior with regard to cognitive flexibility (e.g., Bialystok, 1999; Bialystok & Martin, 2004); this advantage is observed using the card-sorting task. Moreover, Yang and Lust (2005) failed to find such an advantage; specifically, their results only confirmed the superiority of bilinguals with regard to the attentional network task and not the card-sorting task. Interestingly, EF plays an important role in scholastic and literacy achievement (e.g., Best, Miller & Naglieri, 2011; Blair & Diamond, 2008). The development of the reading skills that are the most important for school readiness highlights the need of EF because these skills have many connections with reading achievement. Supposedly, reading skills predict performance on EF tasks but not overall cognitive abilities that is, IQ (e.g., Booth, Boyle & Kelly, 2013). During reading, the suppression of irrelevant information from the text to continuously focus only on relevant information (Gernsbacher, 1993) involves EF such as WM, updating and shifting (e.g., de Jong, 1998; Swanson, Leilani, Michael & Jill, 2004; van der Sluis, de Jong & van der Leij, 2007). Thus, inefficient inhibitory control is likely associated with poor reading skills (e.g., Peng, Sha & Beilei, 2013; Swanson, Howard & Saez, 2006; Swanson, Kehler & Jerman, 2010). Wang and Gathercole (2013) claimed that this deficiency is because the central EF is the attentional control sub-system of WM (Baddeley, 1996). However, sometimes the dissociative findings concerning RD and WM have remained inconclusive (Savage, Lavers & Pillay, 2007), and numerous studies have reported no specific deficiencies in the WM of children with RD (e.g., Pickering & Gathercole, 2004; van der Sluis, van der Leij & de Jong, 2005). In addition, da Fontoura and Siegel (1995) found that Canadian-Portuguese bilingual and monolingual children with RD performed equally on a WM task. Experiences of RD are extremely common among school children (e.g., Grigg, Donahue & Dion, 2007). Similarly, bilingualism is a common phenomenon (e.g., Bialystok, 2001). The population of immigrant children with different minority (first) languages than the majority language is now commonplace throughout the world. Sweden, an immigrant-welcoming country, is not exceptional in this regard. According to the 2012 data from Statistics Sweden (SCB, 2014), the Iranian immigrant population was 65,649. Usually, immigrant children (including Iranians) have learned a first language from birth and began to learn Swedish following immigration, usually through the Swedish educational system. Not surprisingly, concerns about developing a minority language in a majority-language setting increase when they are linked to the presence of RD. Arguably, reading skills are the greatest necessity for children who learn a second language (Lynch & Hudson, 1991). The prevalence of RD is relatively high among bilinguals. Taube (1996) declared that although immigrant children in © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd

Scand J Psychol 56 (2015)

Sweden can decode words easily, they show poor performance in reading comprehension. As Baddeley (1986) stated, children with specific RD face challenges in learning new words in a novel language because any deficiency that is associated with a phonological module would hamper the handling of a new language (Baddeley, Gathercole & Papagno, 1998). Notably, such phonological impairments are not allied with general cognitive functioning (Lundberg, 1999) and have been considered as the major obstacle to second-language learning among children with specific reading disability (Lundberg, 2002). The present study had a dual focus (toward bilingualism and RD); it sought to examine a fairly neglected subgroup of the Swedish population: Iranian-Swedish bilingual children. This segment of the bilingual population in Sweden has not been examined with regard to EF. These languages (Swedish and Farsi) differ dramatically in terms of their vocabularies, alphabets, syntaxes and phonologies. Given the generally observed enhancement of EF among bilinguals on the one hand and the documented impairments to these functions with regard to RD on the other, we used a cross-sectional design to investigate whether bilingualism (as the independent variable) compensates for the expected underperformances of children with RD. The study tasks were expected to offer an advantage to bilinguals; however, children with RD were presumed to be impaired in performing these tasks. Notably, three tasks were employed to examine different cognitive levels: attentional/inhibitory control, WM, and problem solving. To consider the bilingual advantage or disadvantage in the presence or absence of RD, two groups of children were selected: normal readers and children with RD. To explore WM, a memory game called “Concentration” was employed. Although this task is not new, it nevertheless provides a relatively robust measure of visuo-spatial WM. Children not only must keep the identity of the cards in memory but also track their spatial arrangements to recall their positions afterward (Schumann-Hengseler, 1996). To test inhibitory control, the Stroop task (Stroop, 1935) was used which is one of the most widely used tasks to measure interference. Participants must suppress prepotent responses to words that are presented in non-corresponding colors (for a review, see MacLeod, 1991). An interference index denotes the differences between response time in neutral and incongruent trials (Henik, 1996), which is correlated with a lower ability to suppress interference. Finally, to test planning ability, the Tower of Hanoi (TOH; Welsh, 1991) was employed. In solving the TOH puzzle, WM (e.g., Welsh, Cicerello, Cuneo & Brennan, 1995), inhibition (e.g., Miyake, Friedman, Emerson, Witzki, Howerter & Wager, 2000), fluid intelligence (e.g., Duncan, Burgess, & Emslie, 1995), or some combination therein are involved (Zook, Davalos, Delosh & Davis, 2004). Performance on all the tasks is then mediated or directly achieved, with WM making the greatest contribution to EF. In line with Grosjean’s (1992) definition of bilingualism, the bilinguals in this study were able to function in either Swedish or Farsi in accordance with actual demands and used both languages daily. In addition, by using three reading tasks to screen for RD, all children who were at risk of experiencing RD (regardless of whether they had been diagnosed) were included as those with RD. The questions asked by the current study

Bilingual children with reading difficulties 299


were whether, bilingualism affects EF performance by causing an increase/decrease in the effect of RD; and whether the linguistic correspondence between two languages affects cognitive outcomes.

METHOD Participants A total of 190 children aged 9–12 years old (88 Iranian-Swedish bilinguals and 102 Swedish monolinguals) were included in the study. Based on reading outcome performances, four groups were employed in the study: Iranian-Swedish bilingual children with or without RD and Swedish monolingual children with or without RD. The descriptive data are presented in Table 1. RD was defined as an inconsistency between reading score and expected reading performance based on age and intelligence. All of the bilingual children had Iranian parents and spoke Farsi at home. They received educational support in reading and writing in their first language (Farsi) for at least one hour per week beginning at 6 years old in their schools. The monolingual children had Swedish parents, and spoke Swedish exclusively at home. As shown in Table 1, the groups were comparable in terms of age, gender and non-verbal IQ. Children with low non-verbal IQ scores (˂35th percentile on the Raven test) were excluded. In addition, separate analyses showed no overall across-group differences by age [F (3, 189) = 0.3, p ˃ 0.30] or gender [v2 (2) = 4.61, p ˃ 0.20]. Accordingly, age and gender were not entered into additional analyses. A commonsense view exists regarding the socioeconomic status (SES) of the immigrant population in Sweden (including Iranians), namely that significant differences do not exist between immigrant and native Swedish families (e.g., Kormi-Nouri, Moniri & Nilsson, 2003). To determine whether the four groups differed in terms of SES, a socioeconomic index was created that measured parents’ occupation and education (Hedman, 2009). A Kruskal-Wallis test was used to determine that no significant differences existed among the four groups with regard to SES (p ˃ 0.50).

Thus, the children had to memorize the content and position of a growing list of pictures. The number of moves and the total time (in seconds) taken by each participant were recorded. The Tower of Hanoi (TOH). This task was primarily designed to measure planning and problem-solving abilities (Welsh, 1991). A three-disk version of the TOH puzzle was built from a rectangular 12 9 6-cm wooden block. Three 9-cm-long pegs were inserted into the wooden base. Three wooden disks of different sizes (2, 3, 4 cm in diameter) were used. For all of the participants, the disks were positioned on the peg to the right, with the largest one at the bottom and the smallest at the top. The goal was to move the disks to the peg to the left. A number of constraints (rules) were applied when performing the task: A disk cannot be placed on another that is larger; only one disk can be moved at a time; and the disks cannot be removed from the puzzle (they must be placed on one of the pegs at all times). Players were asked to perform the task as quickly as possible and use the fewest number of moves. The minimum number of moves for the three-disk version of the task is 7. The test leaders recorded the number of moves and the total time (in seconds) taken to solve the task. Stroop task. A paper and pencil, blocked color Stroop task was used. This procedure consists of color naming and word reading with congruent and incongruent trials as the control and experimental conditions, respectively. Each condition included two test sheets, each with 20 items. In the congruent condition, the items were the words of colors printed in those colors. The child was asked to name the colors in the first condition and read the words exactly as they were in the second condition. The incongruent condition also had 20 items per sheet; however, they were written in different colors (e.g., the word “red” was written in green ink. In the incongruent condition, the children were first asked to name the colors of the stimuli regardless of the actual written words. Next, they were asked to read the words regardless of the ink color (as quickly and accurately as possible). The presentation order of the sheets and conditions was held constant across participants. The congruent condition was always administered before the incongruent condition. The test leaders recorded the response time (RT, in seconds) for each condition.

Procedure Test battery Three EF tasks were used in this study. Concentration (a memory game). This task uses a deck of picture cards (with pictures on one side), with pairs of cards that are exactly the same (Schumann-Hengseler, 1996). Although nearly all of the children were familiar with this game, they were nevertheless given a clear description of the rules. The 5 9 5 cm cards were shuffled and spread into an 8 9 4 matrix composed of 16 pairs. The picture sides were face down, and the spatial positioning of the cards was the same for all participants. Each child started by turning over two cards and looking at them. If the cards matched, then they were taken out of the matrix. If not, then the child had to place the cards face down in their original positions, and so on. The task was over when all 16 pairs had been matched by the player.

Data collection was performed in several phases. First, we obtained a random selection of 5,000 registered names and addresses of 9 to 12 year-olds from the Swedish Tax Agency (Skatteverket). These chil€ dren lived in five major Swedish cities: Stockholm, Uppsala, Orebro, Gothenburg, and V€aster as. A total of 954 participants were chosen based on their Iranian origin. The remaining participants were either Swedish (all of whom were invited to participate) or immigrants with home countries other than Iran (all of whom were excluded). A clear and detailed description of the study plan and procedure as well as a consent form to be completed by the parent(s)/guardian(s) were sent to the children’s registered addresses. On the consent form, parents were also asked whether they had found or thought that their child might be having problems with reading. The parents were asked to reply by post, which required active involvement on their part. In sum, 765 parents replied; of these parents,

Table 1. Descriptive and screening data across groups Age Groups Bilingual Control RD Monolingual Control RD

Gender

Raven

Number

M (SD)

p

Boys

Girls

M (SD)

p

45 41

10.62 (1.11) 10.71 (1.27)

0.71

16 24

29 17

42.04 (3.79) 42.40 (2.96)

0.59

59 45

10.39 (0.96) 10.73 (0.98)

0.10

27 20

32 25

42.51 (2.56) 42.36 (2.99)

0.80

© 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd

Performance in percentile

300 N. Jalali-Moghadam and R. Kormi-Nouri 70

Scand J Psychol 56 (2015) groups’ performances on the three reading tasks (as percentiles of the correct scores). Furthermore, the colored progressive matrices of the Raven test, which have been used to measure fluid intelligence (e.g., Court & Ravens, 1982), were administered to all the children to control for intelligence. No significant across-group differences were found (p ˃ 0.80). All the materials were in Swedish and administered at school during a session coordinated in advance with the principals and teachers responsible. A trained test leader separately interviewed each child. The full interview session took approximately 90 minutes (including one break). The Swedish children were not intensively exposed to any language other than Swedish at the time of the study; therefore, they had very limited language proficiency in a second language. Because many researchers have used a self-rating scale to determine language proficiency (Francis, 1999), the children were given a questionnaire to assess their background language factors arising from language use at home and school. The results are shown in Table 2. All of the bilingual children (with RD and control) were taught Farsi as their first language, although they reported being better at speaking Swedish than Farsi. According to Namei (2008), Farsi is the primary language used at home among Iranian children in Sweden (especially older children) when communicating with their parents, whereas Swedish is the most frequently used language outside home and in school by younger immigrant children. Our bilingual children showed a similar general pattern of language use. The Regional Research Ethics Committee in Uppsala, Sweden approved this study.

word reading

60

Psuedo-word reading

50

words-chain

40 30 20 10 0 Bil-RD

Mono-RD

Bil-con

Mono-con

Fig. 1. Reading performances of four groups on three reading tasks (in percentiles). Bil-RD: bilinguals with RD, Mono-RD: monolinguals with RD, Bil-con: control bilinguals (without RD), Mono-con: control monolinguals. Bars represent percentage.

467 permitted their children to participate, whereas the rest did not. As expected, an uneven participation rate was found across the groups (100 children with RD vs. 367 children without RD). Because of certain practical problems (e.g., the unexpected absence of children or difficulties in making school arrangements), numerous children did not partici€ pate. Ultimately, the study had 190 participants: 54 from Orebro, 57 from Stockholm, 25 from V€aster as, 18 from Uppsala, and 36 from Gothenburg. After obtaining parental consent, schools and teachers were contacted. Following a parental report of RD with the child, teachers were asked (and interviewed) via telephone or in person whether they had found that the student had RD. In all cases but one (which was excluded), parents’ and teachers’ reports of the child’s RD were consistent. To confirm this consistency, all children were tested using three reading tasks including word and non/pseudo-word reading and word chains. On the word-reading task, the children had to read a list of 52 meaningful Swedish words over 5 minutes as fast and accurately as possible (e.g., Johansson, 2010; Miller-Guron, 2002). On the non/pseudo-wordreading task, the children read 49 non/pseudo words from left to right and from top to bottom. They were instructed not to focus on the meanings of the words but just to read them as they sounded (e.g., Johansson, 2010). Finally, on the word-chains task, children were required to detect and separate as many meaningful words as they could from 50 chains containing several words without any spaces or delimiters (e.g., Jacobson, 2004; Johansson, 1999). Only bilingual and monolingual children who had scores lower than 25% of the reading performance expected for their age and intelligence were allocated into the RD groups. According to several researchers, poor readers are those who score below the 25th percentile (e.g., Bourassa & Treiman, 2003; Lennox & Siegel, 1996). Figure 1 shows the

RESULTS The descriptive data (means of moves and total time) for all dependent variables are shown in Table 3. A series of analyses of variance (ANOVAs) were applied separately to the data for each task, with all variables treated as between-group variables. Regarding concentration and the TOH task, a series of two-way (reading: with or without RD 9 language: bilingual or monolingual) ANOVAs were applied for both the move and time data. Due to the Stroop task, the RT data were analyzed across three levels: Color Naming, Word Reading and interference indices. A summary of the ANOVA analyses is presented in Table 4. As Tables 3 and 4 show, no significant differences were generally observed between the bilingual and monolingual groups. In terms of RD, however, speed performance decreased significantly, and this decline was more obvious among bilinguals than

Table 2. Response means on the Language History Questionnaire Bilinguals

Years of residence in Sweden (bilinguals) Self-rating scores of different language abilities Swedish Listening Speaking Reading Writing Farsi Listening Speaking Reading Writing

Monolinguals

RD

without RD

p

7.9

8.1

0.21

3.6 4.0 1.1 1.5

4.4 4.4 4.3 3.9

0.00 0.01 0.00 0.00

3.2 2.2 1.0 1.0

4.1 2.6 2.2 2.0

0.00 0.11 0.00 0.00

Note: For the self-rating scale, 1 = very poor to 5 = very good. © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd

RD

without RD

p

3.8 4.2 1.4 2.5

4.5 4.6 3.9 3.8

0.00 0.00 0.00 0.00


Scand J Psychol 56 (2015) Table 3. Descriptive data (means and standard deviations) of participants across language groups and executive functioning tasks Concentration

Groups

TOH puzzle

Moves

Time (sec.)

Moves

Time (sec.)

M (SD)

M (SD)

M (SD)

M (SD)

Bilingual Control 40.64 RD 44.51 Monolingual Control 35.63 RD 40.11

(27.24) 162.47 (60.57) 11.64 (7.49) 45.62 (29.48) (15.72) 221.81 (101.74) 15.73 (6.59) 98.35 (48.21) (5.83) 182.15 (58.19) (12.09) 193.86 (48.88)

11.37 (8.00) 56.81 (46.07) 12.16 (4.85) 75.67 (41.10)

Stroop Control

Naming Control RD Reading Control RD

monolinguals. To assess the Stroop effect further, interferenceindex scores were computed as approximate difference ratios between the incongruence and control (congruence) conditions for each group and by using naming and reading as the control conditions/baselines (e.g., Delaloye, Moy, Baudois et al., 2009). This strategy enabled us to control for participant differences with regard to inhibition processing speed (e.g., Borella, Delaloye, Lecerf, Renaud & de Ribaupierre, 2009). As Fig. 2 shows, the greatest interference scores were observed in the color naming condition among the bilingual children with RD. By contrast, bilinguals without RD had the lowest interference scores in the word reading condition, which suggests that bilingualism has a relatively large positive effect when reading inconsistent material.

Incongruence

Bilingual

Monolingual

Bilingual

Monolingual

M (SD)

M (SD)

M (SD)

M (SD)

9.59 (2.39) 12.83 (2.95)

11.95 (2.47) 11.62 (2.57)

14.61 (7.98) 26.10 (5.36)

16.00 (5.91) 22.62 (10.76)

10.61 (2.36) 17.12 (6.70)

10.75 (2.66) 15.31 (2.69)

13.14 (4.39) 28.29 (9.05)

15.80 (6.48) 29.18 (10.60)

Note: Stroop RT’s data are presented in here.

DISCUSSION The present study examined the performance of bilingual and monolingual children with RD across three EF tasks compared with controls (i.e., those without RD). The results provided support for the dissociation hypothesis, such that although bilingualism can improve speed performance under normal conditions, bilingualism combined with the presence of RD lowers response retrieval. Interestingly, these positive and negative outcomes were observed with regard to time management rather than the move indicators of EF. Findings regarding the bilingualism

Table 4. ANOVA summaries for main and interaction effects across executive functioning tasks Moves

Main effect of language Concentration TOH Stroop: Naming Stroop: Reading

Time (sec.)

MSE

F

975.56 126.91

3.55 2.62

778.51 291.85

2.83 6.03**

60286.80 59769.52 98.30 3895.81 1411.34 9671.74 14.95 9.22

12.73* 33.82*** 14.64*** 66.01*** 94.36*** 158.92*** 31.22*** 22.22***

10.46 102.02

0.03 2.10

23875.81 10749.55 142.66 251.25 40.66 34.28 0.60 0.54

5.02** 6.08** 21.25*** 4.25** 2.71 0.49 0.12 1.32

congruence incongruence congruence incongruence

Interference index: Naming Interference index: Reading Main effect of reading Concentration TOH Stroop: Naming Stroop: Reading


Interference index: Naming Interference index: Reading Interaction effects Concentration TOH Stroop: Naming Stroop: Reading


Interference index: Naming Interference index: Reading * p ˂ 0.001, ** p ˂ 0.05, *** p ˂ 0.01. © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd

MSE

280.69 691.20 16.44 36.16 34.08 152.89 1.36 1.52

F

0.05 0.39 2.44 0.61 2.27 2.51 2.48 3.67**

302 N. Jalali-Moghadam and R. Kormi-Nouri Bil-RD

Intterference index scores

1.4

Mono-RD

Bi-con


Mono-con

p =[.31]

1.2

p =[.14]

1 0.8

p =[.08]

p =[.06]

0.6 0.4 0.2 0

Naming Interference Index

Reading Interference Index

Fig. 2. Color Stroop interference index scores across groups (contrasting bilinguals with RD and monolinguals with RD as well as normal reader bilinguals with normal reader monolinguals) with Naming and Reading as control conditions. Bars represent standard error.

effect (in terms of RD) are discussed first; next, this effect will be considered under RD and normal reading conditions. The most prominent finding of the present study was that, in the case of joint bilingualism and RD, performances deteriorated such that bilinguals with RD generally presented poorer performances than monolinguals with RD. Given that bilingual children with RD are particularly affected by the privileges and adversities of EF, it is likely that the intensity and effect of EF impoverishment due to RD would be much greater than the enrichment of EF generated by bilingualism. In these cases, the adversities outweigh the privileges such that the latter will be countervailed. Given that these deficiencies are crucial (albeit helpful under normal conditions), bilingualism will not improve performance. As mentioned earlier, WM is an executive component that is likely shared, in essentially the same proportions, across virtually all EF. Given the cross-sectional nature of the data in this study, it was not possible to address its possible causes. Accordingly, we cannot draw any conclusions regarding the levels of reading or bilingualism at which WM contributed most or was possibly engaged to a greater extent. Nevertheless, such a finding would re-confirm that EF is impaired in children with RD. In turn, it would be reasonable to suppose that these functions might not work properly under difficult reading conditions, although they should under the normal conditions of bilingualism. In line with Baddeley et al. (1998), we postulate that the possible impairments to phonological properties in the WM construct (i.e., the phonological loop) hinder children with RD, or at least confront them with many of the challenges associated with second-language learning and language management. This sub-system likely plays an important role not only in reading but also in learning new words from a second language. Lundberg (2002) highlighted this notion by proposing that such a phonological disability would, in turn, negatively affect second-language learning in that language acquisition depends extensively on the involvement of high phonological skill levels. Similarly, in light of the poor performance of bilinguals with RD on the WM task, we argue that deficiency in WM commonly affects both reading and second-language learning (Swanson et al., 2004); therefore, performance is inevitably and negatively affected. © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd

da Fontoura and Siegel (1995) examined Portuguese-English bilinguals and monolinguals with RD using WM and reading tasks. Although they observed the same level of poor performance among bilingual and monolingual groups with RD, we found that our sample of bilinguals with RD completed the task more slowly than monolinguals with RD. The task administered by them consisted of supplying the missing part(s) of earlier presented sentences, which the children produced orally. By contrast, to control for the anticipated verbal advantage of monolinguals, we selected the Concentration game, which addresses the visuo-spatial domain, and therefore the non-verbal information present in WM. da Fontoura and Siegel (1995) measured the number of correctly remembered items to complete the phrases as the only measure of WM performance. By contrast, we measured performance as both the number of card moves (as a qualitative measurement) and time required (as a quantitative measurement). Similarly, the slower performances of bilinguals with RD on the TOH and Stroop tasks can be discussed in terms of the negative effect of RD on EF. The present data obtained by using three executive functioning tasks, straightforwardly demonstrated lower levels of performance among children with RD compared with controls. This finding is in line with previous studies suggesting that the involvement of EF in reading is essential (e.g., Carretti, Borella, Cornoldi & De Beni, 2009; van der Sluis et al., 2007); furthermore, RD have been consistently shown to cause impairments in WM (e.g., Swanson et al., 2010), specifically because of the inferiority of the executive center within this construct (e.g., Wang & Gathercole, 2013). In addition, similar findings were observed for the TOH: RD were so disabling that they contributed negatively to planning, especially with regard to time consumption. Aguilar-Alonso and Moreno-Gonzalez (2012) found that children with specific reading disabilities showed lower performances on the Tower subtest in the attention and executive functions domains, which it was claimed is similar to TOH and interact with spatial and orienting components. Furthermore, RD generally (and specifically across naming condition), hampered inhibitory control on the Stroop task. In this case, we infer that the uniquely efficacious control mechanism used by bilinguals (Bialystok, 2001), and even by bilingual children who are constrained by RD, is principally intact in competent practices but not less difficult ones. At some point, this assumption suggests that the mechanism is specifically sensitive to incongruity or complexity; thus, congruent/less difficult materials might be treated in a relatively insensitive manner. However, this explanation concerns an infrequent observation that should be investigated further. Regarding the general differences between bilinguals and monolinguals, we found that although bilinguals took less time than monolinguals, this difference was not significant on the WM task. This finding (comparable performances) is in line with the results of some previous studies (e.g., Bialystok, Craik & Luk, 2008; Bonifacci et al., 2011; Engel de Abreu, 2011). The TOH data followed the same pattern; despite the lack of significance, bilingualism generally predicted faster performances. Due to the Stroop task and by interference index scores as more reliable assessments of the Stroop effect, bilingualism



produced larger and smaller interference rates in the Naming and Reading tasks, respectively. This finding supports the idea that bilingualism provides an advantage on occasions where greater demands exist on inhibitory control. Reading incongruent items requires inhibition; however, Naming places fewer demands on inhibition. Along this line, Bialystok and Martin (2004) showed that bilingualism was associated with differential outcomes on tasks with disparate levels of representational demands. Although bilinguals and monolinguals were observed as performing equally as well on tasks with high semantic demands, bilinguals outperformed monolinguals on perceptual tasks. It is usually presumed that every attentional task concerns a specific cognitive domain. Cognitive processes are divided into two categories: attentional control and the analysis of representational knowledge (Bialystok, 1993). Bilinguals are more efficient at acquiring control over attention, but they do not differ greatly from monolinguals with regard to representational knowledge (Bialystok, 2001). This systematic categorization has provided a practical framework for research attempting to distinguish between more difficult tasks (belonging to the former category) and less difficult tasks (belonging to the latter category) of different types (e.g., Bialystok & Codd, 1997; Bialystok & Majumder, 1998). With regard to the interference index, the finding of a smaller index among bilinguals than monolinguals in reading the incongruent items might become disputable when such a condition demands higher levels of attentional control compared with Naming. In relation to the idea that an overall bilingual advantage exists on more difficult tasks, it is reasonable to link this finding to the enhanced ability of bilinguals to address inhibitions at greater levels of complication (i.e., reading incongruences). This study also addressed the role of correspondence between Farsi and Swedish, which (although both languages have alphabetic scripts) is low compared with that of two Western languages (e.g., English and Swedish). To our knowledge, no contrast study has specifically compared these two languages with regard to their typological aspects. However, some studies have found that numerous languages (including Farsi) are remarkably different from a Western language such as Swedish with regard to typological differences (e.g., morphologically; see Philipsson, 2007). As some researchers have shown (e.g., Bialystok et al., 2003; Brauer, 1998; Kormi-Nouri et al., forthcoming), the similarity between languages positively predicts the benefits of bilingualism and cognitive outcome performance. Language similarity has occasionally been studied with regard to the phonological and orthographical aspects of their words, which might influence between/within-language interference on the Stroop task (e.g., Fang, Tzeng & Alva, 1981). Given that Farsi and Swedish are dissimilar both phonologically and orthographically; their dissimilarities might affect the performances reported in this study. Some of the methodological limitations should be noted. The conclusions that can be drawn from our results might not be precise enough to be generalized extensively. For example, the Stroop test used here was a standard paper-and-pencil blocked version; in contrast with the item-by-item computerized version, RTs are recorded as the sum of all trials, including errors and omissions (Salo, Henik & Robertson, 2001). Therefore, the present study did not specifically include errors, which (as is © 2015 Scandinavian Psychological Associations and John Wiley & Sons Ltd

generally suggested) would provide a more precise assessment of the Stroop effect. In addition, our results were not based on bilingual data obtained from participants using their first language; therefore, they are limited to accounts in the second (i.e., majority) language. Given this limitation, our results should be treated with caution in terms of generalization and interpretation. Adopting a two-language strategy most likely would have helped us to address the complexities raised by the over- and underdiagnosis of bilingual children with RD (Hedman, 2009, 2012). By investigating both languages, it would have been possible to show that the principals of phonological and linguistic properties can be transferred from the first to the second language (e.g., da Fontoura & Siegel, 1995; Wade-Woolley & Geva, 2000). Then, a conclusion could be drawn with regard to the notion that bilingualism cannot have specific positive effects or compensate in terms of RD. Rather, it is possible that other variables play a role in producing the results, such as different levels of language proficiency or reading competencies/skills. In sum, consistent with the prevailing general view, bilingualism appears to be an overall advantage for cognitive outcomes; however, this effect is not true of all the findings, which is in line with studies discussed above. Furthermore, this result seems to hold true with regard to RD: the overall findings of this study concern the awkward negative effect of RD which prevented bilinguals from improving their reading performances.

REFERENCES & Moreno-Gonzalez, V. (2012). Neuropsychological Aguilar-Alonso, A. differences between samples of dyslexic and reader children by means of NEPSY. Anuario de Psicologıa, 42, 35–50. Baddeley, A. D. (1986). Working memory. Oxford: Clarendon Press. Baddeley, A. D. (1996). Exploring the central executive. Quarterly Journal of Experimental Psychology, 49A, 5–28. Baddeley, A. D. (2000). The episodic buffer: A new component of working memory? Trends in Cognitive Sciences, 4, 417–423. Baddeley, A., Gathercole, S. & Papagno, C. (1998). The phonological loop as a language learning device. Psychological Review, 105, 158–173. Best, J. R., Miller, P. H. & Naglieri, J. A. (2011). Relations between executive function and academic achievement from ages 5 to 17 in a large, representative national sample. Learning and Individual Differences, 21, 327–336. Bialystok, E. (1993). Metalinguistic awareness: The development of children’s representations of language. In C. Pratt & A. Garton (Eds.), Systems of representation in children: Development and use (pp. 211–233). Chichester: Wiley & Sons. Bialystok, E. (1999). Cognitive complexity and attentional control in the bilingual mind. Child Development, 70, 636–644. Bialystok, E. (2001). Bilingualism in development: Language, literacy, and cognition. New York: Cambridge University Press. Bialystok, E. & Codd, J. (1997). Cardinal limits: Evidence from language awareness and bilingualism for developing concepts of number. Cognitive Development, 12, 85–106. Bialystok, E., Craik, F. I. M., Klein, R. & Viswanathan, M. (2004). Bilingualism, aging, and cognitive control: Wvidence from the Simon task. Psychology and Aging, 19, 290–303. Bialystok, E., Craik, F. I. M. & Luk, G. (2008). Cognitive control and lexical access in younger and older bilinguals. Journal of Experimental Psychology: Learning, Memory, and Cognition, 34, 859–873. Bialystok, E., Luk, G., Peets, K. F. & Yang, S. (2010). Receptive vocabulary differences in monolingual and bilingual children. Bilingualism: Language and Cognition, 13, 525–531.

304 N. Jalali-Moghadam and R. Kormi-Nouri Bialystok, E. & Majumder, S. (1998). The relationship between bilingualism and the development of cognitive processes in problem solving. Applied Psycholinguistics, 19, 69–85. Bialystok, E., Majumder, S. & Martin, M. (2003). Developing phonological awareness: Is there a bilingual advantage? Applied Psycholinguistics, 24, 27–44. Bialystok, E. & Martin, M. M. (2004). Attention and inhibition in bilingual children: Evidence from the dimensional change card sort task. Developmental Science, 7, 325–339. Blair, C. & Diamond, A. (2008). Biological processes in prevention and intervention: The promotion of self-regulation as a means of preventing school failure. Development and Psychopathology, 20, 899–911. Boonstra, A. M., Oosterlaan, J., Sergeant, J. A. & Buitelaar, J. K. (2005). Executive functioning in adult ADHD: A metaanalytic review. Psychological Medicine, 35, 1097–1108. Booth, J. N., Boyle, J. M. E. & Kelly, S. W. (2013). The relationship between inhibition and working memory in predicting children’s reading difficulties. Journal of Research in Reading, 37, 84–101. Bonifacci, P., Giombini, L., Bellocchi, S. & Contento, S. (2011). Speed of processing, anticipation, inhibition and working memory in bilinguals. Developmental Science, 14, 256–269. Borella, B., Delaloye, C., Lecerf, T., Renaud, O. & de Ribaupierre, A. (2009). Do age differences between young and older adults in inhibitory tasks depend on the degree of activation of information? European Journal of Cognitive Psychology, 21, 445–472. Bourassa, D. & Treiman, R. (2003). Spelling in children with reading disability: Analyses from the Treiman-Bourassa early spelling test. Scientific Studies of Reading, 7, 309–333. Brauer, M. (1998). Stroop interference in bilinguals: The role of similarity between the two languages. In A. F. Healy, & L. E. Bourne Jr (Eds.), Foreign language learning: Psycholinguistic studies on training and retention (pp. 317–337). Mahwah, NJ: Lawrence Erlbaum. Carretti, B., Borella, E., Cornoldi, C. & De Beni, R. (2009). Role of working memory in explaining the performance of individuals with specific reading comprehension difficulties: A meta-analysis. Learning and Individual Differences, 19, 246–251. Colzato, L. S., Bajo, M. T., van den Wildenberg, W., Paolieri, D., Nieuwenhuis, S., La Heij, W. & Hommel, B. (2008). How does bilingualism improve executive control? A comparison of active and reactive inhibition mechanisms. Journal of Experimental Psychology: Learning, Memory, and Cognition, 34, 302–312. Costa, A., Hernandez, M. & Sebastian-Galles, N. (2008). Bilingualism aids conflict resolution: Evidence from the ANT task. Cognition, 106, 59–86. Court, J. H. & Raven, J. (1982). Summaries of reliability, validity, and normative studies for Raven’s Progressive Matrices and Vocabulary Scales. In A manual for Raven’s progressive matrices and Mill Hill vocabulary scales (Research Supp. No. 2). London: H. K. Lewis. da Fontoura, H. A. & Siegel, L. S. (1995). Reading, syntactic, and working memory skills of bilingual Portuguese-English Canadian children. Reading and Writing: An Interdisciplinary Journal, 7, 139–153. de Jong, P. F. (1998). Working memory deficits of reading disabled children. Journal of Experimental Child Psychology, 70, 75–96. Delaloye, C., Moy, G., Baudois, S., De Bilbao, F., Dubois Remund, C., Hofer, F., Ragno Paquier, C., Weber, K., Urben, S. & Giannakopoulos, P. (2009). The contribution of aging to the understanding of the dimensionality of executive functions. Archives of Gerontology and Geriatrics, 49, 51–59. Diamond, A. (2013). Executive functions. Annual Review of Psychology, 64, 135–168. Duncan, J., Burgess, P. W. & Emslie, H. (1995). Fluid intelligence after frontal lobe lesions. Neuropsychologia, 33, 261–268. Engel de Abreu, P. M. J. (2011). Working memory in multilingual children: Is there a bilingual effect? Memory, 19, 529–537. Engle, R. W., Tuholski, S. W., Laughlin, J. E. & Conway, A. R. A. (1999). Working memory, short term memory, and general fluid intelligence: A latent variable approach. Journal of Experimental Psychology: General, 128, 309–331.


Scand J Psychol 56 (2015) Fang, S. P., Tzeng, O. J. L. & Alva, L. (1981). Intralanguage vs. interlanguage Stroop effects in two types of writing systems. Memory and Cognition, 9, 609–617. Francis, W. S. (1999). Cognitive integration of language and memory in bilinguals: Semantic representation. Psychological Bulletin, 125, 193–222. Gernsbacher, M. A. (1993). Less skilled readers have less efficient suppression mechanisms. Psychological Science, 5, 294–298. Gollan, T. H. & Acenas, L. A. (2004). What is a TOT? Cognate and translation effects on tip-of-the-tongue states in Spanish-English and Tagalog-English bilinguals. Journal of Experimental Psychology: Learning, Memory, and Cognition, 30, 246–269. Gollan, T. H., Montoya, R. I., Fennema-Notestine, C. & Morris, S. K. (2005). Bilingualism affects picture naming not picture classification. Memory and Cognition, 33, 1220–1234. Grigg, W, Donahue, P & Dion, G. (2007). The nation’s report card: 12th-grade reading and mathematics 2005 (NCES Report No. 2007– 468). Washington, DC: U.S. Department of Education, National Center for Education Statistics. Grosjean, F. (1992). Another view of bilingualism. In R. Harris (Ed.), Cognitive processing in bilinguals (pp. 51–62). Amsterdam: Elsevier. Hedman, C. (2009). Dyslexi p a tv a spr ak. En multipel fallstudie av spansksvensktalande ungdomar med l€as- och skrivsv arigheter. Akademisk avhandling, Centrum f€ or tv aspr akighetsforskning, Stockholms universitet. Hedman, C. (2012). Dyslexia profiling in Spanish-Swedish speaking adolescents. International Journal of Speech-Language Pathology, 14, 509–519. Henik, A. (1996). Paying attention to the Stroop effect? Journal of the International Neuropsychological Society, 2, 467–470. Hernandez, M., Costa, A., Fuentes, L. J., Vivas, A. B. & SebastianGalles, N. (2010). The impact of bilingualism on the executive control and orienting networks of attention. Bilingualism: Language and Cognition, 13, 315–325. Ivanova, I. & Costa, A. (2008). Does bilingualism hamper lexical access in highly-proficient bilinguals? Acta Psychologica, 127, 277–288. Jacobson, C. (2004). Letter-word chains, manual. Stockholm: Psykologif€ orlaget. Johansson, M.-G. (1999). MG-kedjor. Fyra korta l€ astest f€ or snabb och € enkel bed€ omning av l€ asf€ ardighet. Ostersund: MG L€as- och skrivkonsult AB. Johansson, M.-G. (2010). Datortr€aning i l€asflyt och stavning. Doktorsavhandling. Ume a universitet, Institutionen f€ or Psykologi. Kormi-Nouri, R., Jalali-Moghadam, N. & Moradi, A.-R. (forthcoming). The dissociative effects of bilingualism on the performance of reading tasks in primary school children. Scandinavian Journal of Psychology. Kormi-Nouri, R., Moniri, S. & Nilsson, L.-G. (2003). Episodic and semantic memory in bilingual and monolingual children. Scandinavian Journal of Psychology, 44, 47–54. Lennox, C. & Siegel, L. S. (1996). The development of phonological rules and visual strategies in average and poor spellers. Journal of Experimental Child Psychology, 62, 60–83. Lundberg, I. (1999). Towards a sharper definition of dyslexia. In I. Lundberg, F. E. Tønnesson, & I. Austad (Eds.), Dyslexia: Advances in theory and practice (pp. 9–29). Dordrecht: Kluwer Academic Publishers. Lundberg, I. (2002). Second language learning and reading with the additional load of dyslexia. Annals of Dyslexia, 52, 165–187. Luo, L., Fergus, I. M. & C., Moreno, S. & Bialystok, E. (2013). Bilingualism interacts with domain in a working memory task: Evidence from aging. Psychology and Aging, 28, 28–34. Lynch, B. K. & Hudson, T. (1991). Reading EST. In M. Celce-Murcia (Ed.), Teaching English as a second or foreign language (2nd edn, pp. 216–232). New York: Newbury House. MacLeod, C. M. (1991). Half a century of research on the Stroop effect: An integrative review. Psychological Bulletin, 109, 163–203. Martin-Rhee, M. M. & Bialystok, E. (2008). The development of two types of inhibitory control in monolingual and bilingual children. Bilingualism: Language and Cognition, 11, 81–93.

Scand J Psychol 56 (2015) Miller-Guron, L. (2002). Cross-linguistic influence on phonological processing in word reading. Doctoral dissertation at University of G€oteborg. Miyake, A., Friedman, N. P., Emerson, M. J., Witzki, A. H., Howerter, A. & Wager, T. D. (2000). The unity and diversity of executive functions and their contributions to complex “frontal lobe” tasks: A latent variable analysis. Cognitive Psychology, 41, 49–100. Morales, J., Calvo, A. & Bialystok, E. (2012). Working memory development in monolingual and bilingual children. Journal of Experimental Child Psychology, 114, 187–202. Mor, B., Yitzhaki-Amsalem, S. & Prior, A. (2014). The joint effect of bilingualism and ADHD on executive functions. Journal of Attention Disorders. doi:10.1177/1087054714527790. Namei, S. (2008). Language choice among Iranians in Sweden. Journal of Multilingual and Multicultural Development, 29, 419–437. Peng, P., Sha, T. & Beilei, L. (2013). The deficit profile of working memory, inhibition, and updating in Chinese children with reading difficulties. Learning and Individual Differences, 25, 111–117. Philipsson, A. (2007). Interrogative clauses and verb morphology in L2 Swedish. Theoretical interpretations of grammatical development and effects of different elicitation techniques. Unpublished dissertation. Stockholm University: Centre for Research on Bilingualism. Pickering, S. J. & Gathercole, S. E. (2004). Distinctive working memory profiles in children with special educational needs. Educational Psychology, 24, 393–408. Roberts, P. M., Garcia, L. J., Desrochers, A. & Hernandez, D. (2002). English performance of proficient bilingual adults on the Boston Naming Test. Aphasiology, 16, 635–645. Salo, R., Henik, A. & Robertson, L. C. (2001). Interpreting Stroop interference: An analysis of differences between task versions. Neuropsychology, 15, 462–471. Salvatierra, J. L. & Rosselli, M. (2011). The effect of bilingualism and age on inhibitory control. International Journal of Bilingualism, 15, 26–37. Savage, R., Lavers, N. & Pillay, V. (2007). Working memory and reading difficulties: What we know and what we don’t know about the relationship. Educational Psychology Review, 19, 185–221. SCB (2014). Statistical Yearbook of Sweden. Stockholm: Statistiska centralbyr an. Schumann-Hengseler, R. (1996). Children’s and adult’s visuospatial memory: The game Concentration. Journal of Genetic Psychology, 157, 77–92. Stroop, J. R. (1935). Studies of interference in serial verbal reactions. Journal of Experimental Psychology, 12, 242–248.


Bilingual children with reading difficulties 305 Swanson, H. L., Howard, C. B. & Saez, L. (2006). Do different components of working memory underlie different subgroups of reading disabilities? Journal of Learning Disabilities, 39, 252–269. Swanson, H. L., Kehler, P. & Jerman, O. (2010). Working memory, strategy knowledge, and strategy instruction in children with reading disabilities. Journal of Learning Disabilities, 43, 24–47. Swanson, H. L., Leilani, S., Michael, G. & Jill, L. (2004). Literacy and cognitive functioning in bilingual and nonbilingual children at or not at risk for reading disabilities. Journal of Educational Psychology, 96, 3–8. Taube, K. (1996). Indvandrarbarns l€ asf€ ardighet. Stockholm: Skolf€ orvaltningen. van der Sluis, S., de Jong, P. F. & van der Leij, A. (2007). Executive functioning in children, and its relations with reasoning, reading, and arithmetic. Intelligence, 35, 427–449. van der Sluis, S., van der Leij, A. & de Jong, P. F. (2005). Working memory in Dutch children with reading and arithmetic related learning deficits. Journal of Learning Disabilities, 38, 207–221. Wade-Woolley, L. & Geva, E. (2000). Processing novel phonemic contrasts in the acquisition of L2 word reading. Scientific Studies of Reading, 4, 295–311. Wang, S. & Gathercole, S. E. (2013). Working memory deficits in children with reading difficulties: Memory span and dual task coordination. Journal of Experimental Child Psychology, 115, 188–197. Welsh, M. C. (1991). Rule-guided behavior and self-monitoring on the Tower of Hanoi disk-transfer task. Cognitive Development, 6, 59–76. Welsh, M., Cicerello, A., Cuneo, K. & Brennan, M. (1995). Error and temporal patterns in Tower of Hanoi performance: Cognitive mechanisms and individual differences. The Journal of General Psychology, 1, 69–81. Yang, S. & Lust, B. (2005). Testing effects of bilingualism on executive attention: Comparison of cognitive performance on two non-verbal tests. BUCLD 29: Proceedings online supplement of the 29th Boston University Conference on Language Development. Somerville, MA: Cascadilla Press. Zook, N. A., Davalos, D. B., Delosh, E. L. & Davis, H. P. (2004). Working memory, inhibition, and fluid intelligence as predictors of performance on Tower of Hanoi and London tasks. Brain & Cognition, 56, 286–292. Received 8 April 2014, accepted 1 December 2014