Research on Individual Differences in Executive Functions: Implications for the Bilingual Advantage Hypothesis

The Effects of Bilingualism on the Executive Control Abilities of the Prader-Willi Syndrome Population

Unlike with the typically developing population, non-typically developing individuals, especially those with intellectual disabilities, have usually been recommended to learn and use only one language, despite perhaps coming from bilingual families or living in multilingual environments. This common practice, however, is not backed by empirical evidence; previous research, although limited, has systematically shown that bilingualism does not have negative effects. This study investigates how bilingualism shapes the executive control abilities of individuals with genetic disorders. Specifically, we compare the interference suppression abilities of Spanish-Catalan bilinguals and Spanish monolinguals with Prader-Willi syndrome. Fifteen participants with Prader-Willi syndrome were recruited in Spain. The bilingual group consisted of seven Spanish-Catalan bilinguals from Catalonia-an officially bilingual territory of Spain-, while the monolingual group was formed by eight Spanish speaking individuals from Madrid-an officially monolingual territory. Participants were administered two widely used psychological tasks: the Flanker Task (a non-language-based task) and the Stroop Task (a language-based task). Three experimental conditions were included in each task: neutral, congruent, and incongruent. Both accuracy and reaction time data were collected and analyzed. The results obtained are consistent between both tasks in showing (i) no detrimental effects of bilingualism; (ii) a high answer accuracy rate; (iii) a practice effect (the more familiar participants became with the tasks the faster their answers became); (iv) sensitivity to an interference effect (higher reaction times for incongruent trials than neutral trials) but not to a clear facilitation effect (lower reaction times for congruent trials than neutral trials). These results, far from being anecdotal, are in line with results from previous research investigating the effects of bilingualism among typically developing individuals as well as non-typically developing individuals with and without genetic disorders. This study not only evidences that Prader-Willi individuals can become bilingual if they are exposed to more than one language, but also that they can do so without showing negative effects at the cognitive level. In fact, taking into account the trend in the descriptive data, if an effect of bilingualism were in place, it would be a positive one. Bilingualism has repetitively been proven to neither be a burden nor to have negative effects for the typically or the non-typically developing population. Thus, as previous researchers have pointed out, there seems to be a clear incongruity between what the research is showing and the actual advice that these individuals and their families are receiving, and this should be amended without further delay.

To Know all is to Forgive all: The Effect of Foreign Experiences on Forgiveness

By going abroad, individuals get the opportunity to explore a new country and to immerse themselves in a new culture. Despite being personally and professionally rewarding, little is known about interpersonal attitudes and behavior change that accompany living abroad experiences. The current research examines whether foreign experiences influence forgiveness. Drawing on the Structure-Appraisal Model of Multicultural Experiences and literature examining the positive effect of foreign experiences on self-control related to the suppression of impulsive retaliation, we propose that international experiences lead to a greater tendency to forgive. As predicted, we found that foreign experiences correlated positively with forgiving motivations toward transgressors across different measures of forgiveness and diverse samples (Studies 1-2). Study three compared forgiveness of individuals who had lived abroad with forgiveness of individuals who had plans to live abroad but had not done so yet. We found consistent support for the hypothesis that living abroad has an impact on forgiveness. By employing an experimental design, Study four established the causal effect of international experiences on forgiveness. Taken together, these findings suggest that when individuals experience foreign cultures, they learn to understand interpersonal conflicts from different perspectives and show greater leniency and forgiveness toward transgressions.

Executive Function Deficits and Borderline Personality Disorder Symptomatology in a Nonclinical Adult Sample: A Latent Variable Analysis

While borderline personality disorder (BPD) symptomatology has been studied extensively in clinical populations, the mechanisms underlying its manifestation in nonclinical populations remain largely understudied. One aspect of BPD symptomatology in nonclinical populations that has not been well studied is cognitive mechanisms, especially in relation to executive functions. To explore the cognitive mechanisms underlying BPD symptomatology in nonclinical populations, we analysed a large-scale dataset of 233 young adults that were administered with nine executive function tasks and BPD symptomatology assessments. Our structural equation modelling did not find any significant relations between latent factors of executive functions and the severity of BPD symptomatology. Contrary to our hypothesis, our result suggests that deficits in executive functions were not a risk factor for BPD symptomatology in the nonclinical young adult sample.

Clear Theories Are Needed to Interpret Differences: Perspectives on the Bilingual Advantage Debate

The heated debate regarding bilingual cognitive advantages remains ongoing. While there are many studies supporting positive cognitive effects of bilingualism, recent meta-analyses have concluded that there is no consistent evidence for a bilingual advantage. In this article we focus on several theoretical concerns. First, we discuss changes in theoretical frameworks, which have led to the development of insufficiently clear theories and hypotheses that are difficult to falsify. Next, we discuss the development of looking at bilingual experiences and the need to better understand language control. Last, we argue that the move from behavioural studies to a focus on brain plasticity is not going to solve the debate on cognitive effects, especially not when brain changes are interpreted in the absence of behavioural differences. Clearer theories on both behavioural and neural effects of bilingualism are needed. However, to achieve this, a solid understanding of both bilingualism and executive functions is needed first.

Executive functions in Persian-speaking preschool children with speech sound disorders and comparison with their typically developing peers

This study aimed to compare working memory, inhibitory control, and cognitive flexibility, the core components of executive functions, among two prevalent subtypes of preschool children with speech sound disorder, i.e., phonological delay (n = 16) and consistent phonological disorder (n = 15), and a group of typically developing children (n = 18). The correlation between executive function components and the accuracy of speech sound production were also investigated. Nonword repetition task and syllable repetition task were used to evaluate the phonological loop of working memory. Backward digit span was administered to examine the central executive of working memory. Cognitive flexibility was assessed using the second selection of the flexible item selection task and inhibitory control using Stroop-like and Go/No-Go tasks. The percentage consonants correct was applied to calculate the accuracy of speech sound production. Results of a one-way multivariate analysis of covariance revealed statistically significant differences between groups in the combined dependent variables after controlling for age (F(14, 80) = 17.289, p < .001, Pillai's trace = 1.503, partial ηƞ² = .752). Typically developing children outperformed in all measurements of executive functions than both speech sound disorder subgroups. Moreover, children with phonological delay performed better in nonword repetition and corrected responses of Stroop-like than consistent phonological disorder group. All executive function measurements also correlated with speech sound production. The results of the present study highlight the importance of including domain-general cognitive skills in current assessment protocols for children with phonological delay and consistent phonological disorders.

Home Language Environment and Executive Functions in Mexican American and Chinese American Preschoolers in Head Start

Research Findings

Using two groups of dual language learners (DLLs), the current study examined links between two developmental constructs closely linked to school readiness: the home language environment (HLE) and executive function (EF). In a sample of 90 children (age range = 38-70 months, 59% girls) from either Mexican American (MA, N = 46) or Chinese American (CA, N = 44) low-income families enrolled in Head Start preschool programs, parents reported on their HLE (home language balance, home English/heritage language activities) and children's EF (inhibitory control and attention shifting) was measured by cognitive tasks. Findings showed preschool-aged DLLs in low-income immigrant families received more heritage language exposure relative to English language exposure at home. Several demographic variables (parental education, per capita income, DLL group, child age of English acquisition, child generation, child English receptive vocabulary) were related to various aspects of HLE. Controlling for covariates, the amount of heritage language activities at home was uniquely and positively related to children's attention shifting.

Practice or Policy

The findings underscore the importance of incorporating language background considerations when designing intervention programs that target HLE and EF in low-income DLLs.

The developmental trajectories of executive function from adolescence to old age

Executive functions demonstrate variable developmental and aging profiles, with protracted development into early adulthood and declines in older age. However, relatively few studies have specifically included middle-aged adults in investigations of age-related differences in executive functions. This study explored the age-related differences in executive function from late childhood through to old age, allowing a more informed understanding of executive functions across the lifespan. Three hundred and fifty participants aged 10 to 86 years-old completed a battery of tasks assessing the specific roles of inhibitory control, working memory, cognitive flexibility, and planning. Results highlighted continued improvement in working memory capacity across adolescence and into young adulthood, followed by declines in both working memory and inhibitory control, beginning from as early as 30-40 years old and continuing into older age. Analyses of planning abilities showed continued improvement across adolescence and into young adulthood, followed by a decline in abilities across adulthood, with a small (positive) change in older age. Interestingly, a dissociation was found for cognitive flexibility; switch costs decreased, yet mixing costs increased across the lifespan. The results provide a description of the developmental differences in inhibitory control, working memory, cognitive flexibility and planning, above any effects of IQ or SES, and highlight the importance of including middle-aged adults in studies seeking to establish a more comprehensive picture of age-related differences in executive function.

Wisconsin Card Sorting Test reveals a monitoring advantage but not a switching advantage in multilingual children

The Wisconsin Card Sorting Test (WCST) is used to test higher-level executive functions or switching, depending on the measures chosen in a study and its goal. Many measures can be extracted from the WCST, but how to assign them to specific cognitive skills remains unclear. Thus, the current study first aimed at identifying which measures test the same cognitive abilities. Second, we compared the performance of mono- and multilingual children in the identified abilities because there is some evidence that bilingualism can improve executive functions. We tested 66 monolingual and 56 multilingual (i.e., bi- and trilingual) primary school children (M_age = 109 months) in an online version of the classic WCST. A principal component analysis revealed four factors: problem-solving, monitoring, efficient errors, and perseverations. Because the assignment of measures to factors is only partially coherent across the literature, we identified this as one of the sources of task impurity. In the second part, we calculated regression analyses to test for group differences while controlling for intelligence as a predictor for executive functions and for confounding variables such as age, German lexicon size, and socioeconomic status. Intelligence predicted problem-solving and perseverations. In the monitoring component (measured by the reaction times preceding a rule switch), multilinguals outperformed monolinguals, thereby supporting the view that bi- or multilingualism can improve processing speed related to monitoring.

Patterns of bilingual language use and response inhibition: A test of the adaptive control hypothesis

Given prior studies that provided inconsistent results, there is an ongoing debate on the issue of whether bilingualism benefits cognitive control. We tested the Adaptive Control Hypothesis, according to which only the intense use of different languages in the same situation without mixing them in single utterances (called dual-language context) confers a bilingual advantage in response inhibition. In a large-scale correlational study, we attempted to circumvent several pitfalls of previous research on the bilingual advantage by testing a relatively large sample of participants and employing a more reliable and valid measurement of constructs (i.e., latent variable approach accompanied by Bayesian estimation). Our results do not support the Adaptive Control Hypothesis' prediction: the intensity of the dual-language context experience was unrelated to the efficiency of response inhibition in bilinguals. The results suggest that the Adaptive Control Hypothesis is not likely to account for the inconsistent results regarding the bilingual advantage hypothesis, at least in the case of the response-inhibition mechanism. At the same time, the study points to the problem of measuring the response-inhibition construct at the behavioral level. No evidence for a robust response-inhibition construct adds to the growing skepticism on this issue in the literature.

Emotion regulation strategies predict weight loss during an inpatient obesity treatment for adolescents

OBJECTIVE

Weight loss during an inpatient obesity treatment is an important predictor of subsequent weight maintenance. However, psychological factors influencing weight loss are not well established. Psychological models suggest some importance of executive functioning and emotion regulation strategies. Therefore, this study investigated whether these factors predict weight loss during an inpatient obesity treatment and whether this effect holds after controlling for general personal and treatment characteristics.

METHOD

A total of 158 adolescents with diagnosed obesity underwent inpatient obesity treatment at a German rehabilitation clinic. Psychological factors (executive functioning and emotion regulation) were measured at admission and used to predict BMI reduction after treatment completion.

RESULTS

More frequent use of reappraisal as an emotion regulation strategy, but not suppression or executive functioning, predicted weight loss at the end of the obesity treatment, even after controlling for age, gender, treatment duration, and BMI at admission.

CONCLUSION

Functional emotion regulation strategies, like reappraisal, might offer an additional target for obesity treatment programmes, complementary to the more traditional components of psychoeducation, physical activity, and caloric restriction.

Do Bilingual Children Have an Executive Function Advantage? Results From Inhibition, Shifting, and Updating Tasks

Purpose

The purpose of this study was to examine differences in performance between monolingual and Spanish-English bilingual second graders (aged 7-9 years old) on executive function tasks assessing inhibition, shifting, and updating to contribute more evidence to the ongoing debate about a potential bilingual executive function advantage.

Method

One hundred sixty-seven monolingual English-speaking children and 80 Spanish-English bilingual children were administered 7 tasks on a touchscreen computer in the context of a pirate game. Bayesian statistics were used to determine if there were differences between the monolingual and bilingual groups. Additional analyses involving covariates of maternal level of education and nonverbal intelligence, and matching on these same variables, were also completed.

Results

Scaled-information Bayes factor scores more strongly favored the null hypothesis that there were no differences between the bilingual and monolingual groups on any of the executive function tasks. For 2 of the tasks, we found an advantage in favor of the monolingual group.

Conclusions

If there is a bilingual advantage in school-aged children, it is not robust across circumstances. We discuss potential factors that might counteract an actual advantage, including task reliability and environmental influences.

Executive Functions and Language: Their Differential Influence on Mono- vs. Multilingual Spelling in Primary School

We aimed at unveiling the role of executive functions (EFs) and language-related skills in spelling for mono- versus multilingual primary school children. We focused on EF and language-related skills, in particular lexicon size and phonological awareness (PA), because these factors were found to predict spelling in studies predominantly conducted with monolinguals, and because multilingualism can modulate these factors. There is evidence for (a) a bilingual advantage in EF due to constant high cognitive demands through language control, (b) a smaller mental lexicon in German and (c) possibly better PA. Multilinguals in Germany show on average poorer German language proficiency, what can influence performance on language-based tasks negatively. Thus, we included two spelling tasks to tease apart spelling based on lexical knowledge (i.e., word spelling) from spelling based on non-lexical strategies (i.e., non-word spelling). Our sample consisted of heterogeneous third graders from Germany: 69 monolinguals (age: M = 108 months) and 57 multilinguals (age: M = 111 months). On less language-dependent tasks (e.g., non-word spelling, PA, intelligence, short-term memory (STM) and three EF tasks testing switching, inhibition, and working memory) performance of both groups did not differ significantly. However, multilinguals performed significantly more poorly on tasks measuring German lexicon size and word spelling than monolinguals. Regression analyses revealed that for multilinguals, inhibition was related to spelling, whereas switching was the only EF component to influence word spelling in monolinguals and non-word spelling performance in both groups. By adding lexicon size and other language-related factors to the regression models, the influence of switching was reduced to insignificant effects, but inhibition remained significant for multilinguals. Language-related skills best predicted spelling and both language groups shared those variables: PA for word spelling, and STM for non-word spelling. Additionally, multilinguals' word spelling performance was also predicted by their German lexicon size, and non-word spelling performance by PA. This study offers an in-depth look at spelling acquisition at a certain point of literacy development. Mono- and multilinguals have the predominant factors for spelling in common, but probably due to superior language knowledge, monolinguals were already able to make use of EF during spelling. For multilinguals, German lexicon size was more important for spelling than EF. For multilinguals' spelling these functions might come into play only at a later stage.

Language experience modulates bilingual language control: The effect of proficiency, age of acquisition, and exposure on language switching

The ability to selectively access two languages characterises the bilingual everyday experience. Previous studies showed the role of second language (L2) proficiency, as a proxy for dominance, on language control. However, the role of other aspects of the bilingual experience - such as age of acquisition and daily exposure - are relatively unexplored. In this study, we used a cued language switching task to examine language switching and mixing in two groups of highly proficient bilinguals with different linguistic backgrounds, to understand how the ability to control languages is shaped by linguistic experience. Our analysis shows that the ability to switch between languages is not only modulated by L2 proficiency, but also by daily L2 exposure. Daily L2 exposure also affects language mixing. Finally, L2 age of acquisition predicts naming latencies in the L2. Together, these findings show that language dominance is characterised by multiple aspects of the bilingual experience, which modulate language control.

Intensity of Multilingual Language Use Predicts Cognitive Performance in Some Multilingual Older Adults

Cognitive advantages for bilinguals have inconsistently been observed in different populations, with different operationalisations of bilingualism, cognitive performance, and the process by which language control transfers to cognitive control. This calls for studies investigating which aspects of multilingualism drive a cognitive advantage, in which populations and under which conditions. This study reports on two cognitive tasks coupled with an extensive background questionnaire on health, wellbeing, personality, language knowledge and language use, administered to 387 older adults in the northern Netherlands, a small but highly multilingual area. Using linear mixed effects regression modeling, we find that when different languages are used frequently in different contexts, enhanced attentional control is observed. Subsequently, a PLS regression model targeting also other influential factors yielded a two-component solution whereby only more sensitive measures of language proficiency and language usage in different social contexts were predictive of cognitive performance above and beyond the contribution of age, gender, income and education. We discuss these findings in light of previous studies that try to uncover more about the nature of bilingualism and the cognitive processes that may drive an advantage. With an unusually large sample size our study advocates for a move away from dichotomous, knowledge-based operationalisations of multilingualism and offers new insights for future studies at the individual level.

Recognizing the Effects of Language Mode on the Cognitive Advantages of Bilingualism

For bilinguals, it is argued that a cognitive advantage can be linked to the constant management and need for conflict resolution that occurs when the two languages are co-activated (Bialystok, 2015). Language mode (Grosjean, 1998, 2001) is a significant variable that defines and shapes the language experiences of bilinguals and consequently, the cognitive advantages of bilingualism. Previous work, however, has not sufficiently tested the effects of language mode on the bilingual experience. In this brief conceptual analysis, we discuss the significance of language mode in bilingual work on speech perception, production, and reading. We offer possible explanations for conflicting findings and ways in which future work should control for its modulating effects.