Differences in cognitive processing? The role of verbal processes and mental effort in bilingual and monolingual children's planning performance.

Past research documents a bilingual advantage in the domain of executive functions (EFs). However, controversial debates have questioned the robustness of those behavioral differences. The current study aimed to better understand the underlying cognitive prerequisites in bilingual students as compared with monolingual students and focused on two processes: the role of verbal processes, on the one hand, and mental effort during task execution, on the other. The use of self-regulatory speech has been found to be related to performance in tasks requiring EFs. For bilinguals who have grown up with two language systems from an early age, those relations are not fully understood. Furthermore, results from neuroimaging studies have shown that bilinguals might exhibit less mental effort in EF tasks. We investigated both processes in German-speaking monolingual elementary school students (n = 33; Mage = 8.78 years) and German-Russian bilingual elementary school students (n = 34; Mage = 8.88 years) solving a planning task. Results showed that monolinguals were impaired by a verbal secondary task in comparison with a motor control condition, whereas bilinguals performed in both tasks at an equal level, indicating a differential role of self-regulatory speech in both language groups. Analyses of changes in pupil diameter revealed less mental effort during task execution for bilingual children as compared with monolingual children. The current study adds to the existing literature by supplying further evidence for cognitive differences between monolingual and bilingual children.

Executive functions in mono- and bilingual children: Factor structure and relations with fluid intelligence.

The effects of bilingualism on executive functions (EFs) and intelligence are still controversially discussed. Most studies have focused on performance differences without considering the underlying structure of cognitive abilities. Thus, we examined whether the structure of EFs and the relations of EFs with intelligence differ between mono- and bilingual children. A total of 240 elementary school children (mean age = 8 years 6 months; 133 monolinguals and 95 bilinguals) performed two tasks measuring working memory, inhibition, cognitive flexibility, and fluid intelligence, respectively. Confirmatory factor analyses showed that one common EF factor provided the best fit to the data in both language groups, indicating that bilingualism is not associated with differences in the EF structure at this age. Moreover, there were no latent performance differences in either EFs or intelligence between mono- and bilingual children. However, we found a stronger relation between a common EF factor and fluid intelligence in bilingual children as compared with monolingual children, implying a closer coupling of EFs and intelligence abilities in bilingual children. This contributes to explaining the previous heterogeneous findings on the task level because more closely coupled cognitive functioning can be slightly beneficial for some tasks and irrelevant or even slightly obstructive for others.

"Hot" executive functions are comparable across monolingual and bilingual elementary school children: Results from a study with the Iowa Gambling Task.

Past research found performance differences between monolingual and bilingual children in the domain of executive functions (EF). Furthermore, recent studies have reported advantages in processing efficiency or mental effort in bilingual adults and children. These studies mostly focused on the investigation of "cold" EF tasks. Studies including measures of "hot" EF, i.e., tasks operating in an emotionally significant setting, are limited and hence results are inconclusive. In the present study, we extend previous research by investigating performance in a task of the "hot" EF domain by both behavioral data and mental effort via pupillary changes during task performance. Seventy-three monolingual and bilingual school children (mean age = 107.23 months, SD = 10.26) solved the Iowa Gambling Task in two different conditions. In the standard task, characterized by constant gains and occasional losses, children did not learn to improve their decision-making behavior. In a reversed task version, characterized by constant losses and occasional gains, both monolinguals and bilinguals learned to improve their decision-making behavior over the course of the task. In both versions of the task, children switched choices more often after losses than after gains. Bilinguals switched their choices less often than monolinguals in the reversed task, indicating a slightly more mature decision-making strategy. Mental effort did not differ between monolinguals and bilinguals. Conclusions of these findings for the bilingual advantage assumption will be discussed.