Anatomical and functional changes in the brain after simultaneous interpreting training: A longitudinal study

Abstract

In the recent literature on bilingualism, a lively debate has arisen about the long-term effects of bilingualism on cognition and the brain. These studies yield inconsistent results, in part because they rely on comparisons between bilingual and monolingual control groups that may also differ on other variables. In the present neuroimaging study, we adopted a longitudinal design, assessing the long-term anatomical and cognitive effects of an extreme form of bilingualism, namely simultaneous interpreting. We compared a group of students starting interpreting training with a closely matched group of translators, before and after nine months of training. We assessed behavioral performance and neural activity during cognitive control tasks, as well as the structural connectivity between brain regions that are involved in cognitive control. Despite the lack of behavioral differences between the two groups over time, functional and structural neural differences did arise. At the functional level, interpreters showed an increase of activation in the right angular gyrus and the left superior temporal gyrus in two non-verbal cognitive control tasks (the Simon task and a color-shape switch task), relative to the translators. At the structural level, we identified a significant increment of the structural connectivity in two different subnetworks specifically for the interpreters. The first network, the frontal-basal ganglia subnetwork, has been related to domain-general and language-specific cognitive control. The second subnetwork, in which the cerebellum and the supplementary motor area (SMA) play a key role, has recently also been proposed as an important language control network. These results suggest that interpreters undergo plastic changes in specific control-related brain networks to handle the extreme language control that takes place during interpreter training.

Taxing the bilingual mind: Effects of simultaneous interpreting experience on verbal and executive mechanisms

“…An additional issue concerns the sensitivity of the dependent variables considered so far in the literature. For example, as noted earlier, measures of accuracy and/or reaction time have yielded no evidence of enhanced inhibitory skills in either ISs (Dong & Xie, 2014; Köpke & Nespoulous, 2006; Van de Putte et al, 2018) or PSIs (Babcock & Vallesi, 2017; Köpke & Nespoulous, 2006; Yudes et al, 2011). However, electrophysiological results suggest that training in at least one interpreting modality (consecutive interpreting) may distinctively modulate event-related potentials underlying monitoring and inhibitory functions (Dong & Zhong, 2017).…”

“…Still, some particular domains might require longer periods of SI practice to exhibit significant enhancements. For example, verbal fluency advantages have been observed in PSIs (Santilli et al, 2018) but not in ISs (Van de Putte et al, 2018) relative to balanced UMs. Similarly, whereas WM skills are systematically boosted both in PSIs and ISs, advantages in STM would seem to be more consistent in the former population.…”

“…Moreover, relevant cognitive systems seem to be rapidly responsive to such stringent conditions. Significant neural and behavioral enhancements can be observed in subjects who completed as little as two semesters of SI training, with the most striking evidence coming from pre/post designs (e.g., Antonova Ünlü & Sağın Şimşek, 2018; Hervais-Adelman et al, 2015, 2017; Van de Putte et al, 2018). Therefore, when subjected to high demands, cognitive systems in bilinguals do not remain unaffected until expert standards are reached; rather, they exhibit swift adaptations visible in the short term, even in adult subjects.…”

“…Admittedly, some studies have failed to report whether their IS or PSI samples were matched for L2 proficiency/experience with UMs (e.g., Bajo et al, 2000; Darò, 1989; Fabbro et al, 1991; Hiltunen et al, 2016; Szarkowska et al, 2018; Tzou et al, 2012). Although interpreter advantages in those cases may well be reflecting the impact of higher language competence, most reports have effectively ruled out this confound (e.g., Aparicio et al, 2017; Babcock & Vallesi, 2017; Elmer & Kühnis, 2016; Hervais-Adelman et al, 2015, 2017; Morales et al, 2015; Santilli et al, 2018; Signorelli et al, 2012; Van de Putte et al, 2018; Yudes et al, 2011, 2013), suggesting that such effects could actually be specifically driven by experience in this particular activity.…”

“…Still, these results should be taken with caution as they were obtained with small sample sizes ( n ≤ 10) and without a systematic assessment of potential confounds, such as L2 proficiency. Actually, not all studies have found differences between ISs and proficient bilinguals in linguistic tasks, as shown by measures of word reading speed (Chincotta & Underwood, 1998) and verbal fluency (Van de Putte et al, 2018).…”