Monolinguals and bilinguals disengage attention differently following conflict and errors: Evidence from ERPs

Bilingualism modifies cognition through adaptation, not transfer

The standard explanation for bilingual effects on cognition is that an aspect of language processing transfers to nonverbal cognitive performance, leading to improvements in executive functioning. However, much evidence is incompatible with that view, and transfer across those domains seems unlikely. The present argument is that bilingual experience modifies cognition through an adaptation to the underlying attention system, making attention more efficient. 'Transfer' focuses on the overlap of specific processes, so task similarity predicts outcomes. By contrast, 'adaptation' focuses on recruitment of the modified resource, so the degree of attention required predicts outcome. In this view, bilinguals require less attentional effort than monolinguals for similar levels of performance, and outperform monolinguals on tasks with high attention demands regardless of task similarity.

The ups and downs of bilingualism: A review of the literature on executive control using event-related potentials

Whether bilingualism enhances executive control (EC) is controversial. This article reviews 24 studies on the bilingual EC effect using event-related potentials (ERPs). It evaluates the evidence based on considerations of neural efficiency, different EC theories, and accounts regarding the locus of the bilingual effect. The review finds some evidence for a positive bilingual impact. This is more consistent for the P3 and response-locked ERPs. Moreover, when considering each component independently, evidence primarily supports a monitoring and secondarily an inhibition locus. Additionally, an N2/ERN (error-related negativity) dissociation (no bilingual N2 effect but positive ERN impact, evident as smaller ERN), coupled with the P3 results, suggest that monitoring may not be the (only) locus of a bilingual effect but (an)other post-monitoring mechanism(s). Attention disengagement also receives some support. Finally, results across studies are largely consistent with the Bilingualism Anterior to Posterior and Subcortical Shift model (BAPSS): Bilingual effects, when found, often manifest as shorter latencies, larger components or wider amplitude effects during earlier (N2, P3) but smaller components or narrower effects during later processing (stimulus-locked negativities and response-locked components). However, this evidence is not unequivocal. Many bilingual-monolingual comparisons reveal null or some suggest negative or opposite to prediction bilingual effects. Second, the scant evidence about which bilingual experiences impact EC is, generally, unclear, while some evidence indicates negative effects. Third, BAPSS is often not confirmed when multiple components are examined within subjects. Finally, this literature is challenged by confounds and small samples. Further research is required to conclude a positive bilingual effect on EC in ERPs.

The Multifaceted Nature of Bilingualism and Attention

Attention has recently been proposed as the mechanism underlying the cognitive effects associated with bilingualism. However, similar to bilingualism, the term attention is complex, dynamic, and can vary from one activity to another. Throughout our daily lives, we use different types of attention that differ in complexity: sustained attention, selective attention, alternating attention, divided attention, and disengagement of attention. The present paper is a focused review summarizing the results from studies that explore the link between bilingualism and attention. For each level of attention, a brief overview of relevant theoretical models will be discussed along with a spotlight on paradigms and tasks used to measure these forms of attention. The findings illustrate that different types and levels of attention are modified by the variety of bilingual experiences. Future studies wishing to examine the effects of bilingualism on attention are encouraged to embrace the complexity and diversity of both constructs rather than making global claims about bilingualism and attention.

Does language context impact the neural correlates of executive control in monolingual and multilingual young adults?

Some previous studies have shown that creating a language context in which words from both languages are interspersed into a flanker task improves executive control performance for bilinguals, but these studies have produced inconsistent results. The studies have used different versions of the task and not included monolinguals, limiting generalization. Here, English-Chinese multilinguals and English monolinguals performed a flanker task while EEG was recorded. There were three language context blocks - English, Chinese, or both - and participants were instructed to ignore the interspersed words. Multilinguals displayed faster flanker RTs and earlier P2 and N2 waveforms than monolinguals. There was also a significant correlation between the P2/N2 latency and reaction times, connecting these waveforms to behavior. Finally, P2 amplitude differed between groups in the mixed context, and language context impacted P3 amplitude for monolinguals but not multilinguals. These results are interpreted in terms of language context effects on monolingual executive function processing and possible difference in bilingual experience between current participants and those in previous studies.

Electrophysiological signatures of attentional control in bilingual processing: Evidence from proactive interference

Monolingual and bilingual participants performed a Proactive Interference task in verbal and nonverbal conditions while EEG was recorded. Behavioral results showed faster responses for bilinguals on interference trials in the nonverbal condition, and electrophysiological results indicated greater attentional control for bilinguals. ROI analyses showed this pattern for bilinguals mainly in the verbal condition, whereas whole brain analyses found this association in both conditions. Frequency power analysis found activity related to interference trials was associated with recruitment of different neural resources for verbal and nonverbal conditions. Nonverbal results indicated beta activity for interference trials in bilinguals and the verbal condition showed this pattern in theta and gamma frequency bands as well, revealing more extensive brain activation in the verbal domain for bilinguals. For monolinguals, frequency power in beta, gamma, and theta were related to facilitation trials. These results suggest different strategies for allocating attention by monolingual and bilingual young adults.

Bilingualism and domain-general cognitive functions from a neural perspective: A systematic review

A large body of research has indicated that bilingualism - through continual practice in language control - may impact cognitive functions, as well as relevant aspects of brain function and structure. The present review aimed to bring together findings on the relationship between bilingualism and domain-general cognitive functions from a neural perspective. The final sample included 210 studies, covering findings regarding neural responses to bilingual language control and/or domain-general cognitive tasks, as well as findings regarding effects of bilingualism on non-task-related brain function and brain structure. The evidence indicates that a) bilingual language control likely entails neural mechanisms responsible for domain-general cognitive functions; b) bilingual experiences impact neural responses to domain-general cognitive functions; and c) bilingual experiences impact non-task-related brain function (both resting-state and metabolic function) as well as aspects of brain structure (both macrostructure and microstructure), each of which may in turn impact mental processes, including domain-general cognitive functions. Such functional and structural neuroplasticity associated with bilingualism may contribute to both cognitive and neural reserves, producing benefits across the lifespan.

Different temporal dynamics after conflicts and errors in children and adults

After perceiving cognitive conflicts or errors, children as well as adults adjust their performance in terms of reaction time slowing on subsequent actions, resulting in the so called post-conflict slowing and post-error slowing, respectively. The development of these phenomena has been studied separately and with different methods yielding inconsistent findings. We aimed to assess the temporal dynamics of these two slowing phenomena within a single behavioral task. To do so, 9-13-year-old children and young adults performed a Simon task in which every fifth trial was incongruent and thus induced cognitive conflict and, frequently, also errors. We compared the reaction times on four trials following a conflict or an error. Both age groups slowed down after conflicts and did so even more strongly after errors. Disproportionally high reaction times on the first post-error trial were followed by a steady flattening of the slowing. Generally, children slowed down more than adults. In addition to highlighting the phenomenal and developmental robustness of post-conflict and post-error slowing these findings strongly suggest increasingly efficient performance adjustment through fine-tuning of cognitive control in the course of development.

Cognitive Control Facilitates Attentional Disengagement during Second Language Comprehension

Bilinguals learn to resolve conflict between their two languages and that skill has been hypothesized to create long-term adaptive changes in cognitive functioning. Yet, little is known about how bilinguals recruit cognitive control to enable efficient use of one of their languages, especially in the less skilled and more effortful second language (L2). Here we examined how real-time cognitive control engagement influences L2 sentence comprehension (i.e., conflict adaptation). We tested a group of English monolinguals and a group of L2 English speakers using a recently-developed cross-task adaptation paradigm. Stroop sequences were pseudo-randomly interleaved with a visual-world paradigm in which participants were asked to carry out spoken instructions that were either syntactically ambiguous or unambiguous. Consistent with previous research, eye-movement results showed that Stroop-related conflict improved the ability to engage correct-goal interpretations, and disengage incorrect-goal interpretations, during ambiguous instructions. Such cognitive-to-language modulations were similar in both groups, but only in the engagement piece. In the disengagement portion, the modulation emerged earlier in bilinguals than in monolinguals, suggesting group differences in attentional disengagement following cognitive control recruitment. Additionally, incorrect-goal eye-movements were modulated by individual differences in working memory, although differently for each group, suggesting an involvement of both language-specific and domain-general resources.