Age of second language acquisition affects nonverbal conflict processing in children: an fMRI study

Abstract

BackgroundIn their daily communication, bilinguals switch between two languages, a process that involves the selection of a target language and minimization of interference from a nontarget language. Previous studies have uncovered the neural structure in bilinguals and the activation patterns associated with performing verbal conflict tasks. One question that remains, however is whether this extra verbal switching affects brain function during nonverbal conflict tasks.MethodsIn this study, we have used fMRI to investigate the impact of bilingualism in children performing two nonverbal tasks involving stimulus–stimulus and stimulus–response conflicts. Three groups of 8–11-year-old children – bilinguals from birth (2L1), second language learners (L2L), and a control group of monolinguals (1L1) – were scanned while performing a color Simon and a numerical Stroop task. Reaction times and accuracy were logged.ResultsCompared to monolingual controls, bilingual children showed higher behavioral congruency effect of these tasks, which is matched by the recruitment of brain regions that are generally used in general cognitive control, language processing or to solve language conflict situations in bilinguals (caudate nucleus, posterior cingulate gyrus, STG, precuneus). Further, the activation of these areas was found to be higher in 2L1 compared to L2L.ConclusionThe coupling of longer reaction times to the recruitment of extra language-related brain areas supports the hypothesis that when dealing with language conflicts the specialization of bilinguals hampers the way they can process with nonverbal conflicts, at least at early stages in life.

Neural correlates of cognitive processing in monolinguals and bilinguals

“…In general, children tend to over‐recruit those same regions that are later engaged more efficiently by bilingual adults. For example, Mohades et al . tested bilingual and monolingual children using the Simon and Stroop tasks and found that bilingual children recruited the bilateral cingulate cortex to a greater extent than monolinguals on conflict trials.…”

Executive control in bilinguals: A concise review on fMRI studies

“…One recent fMRI study adopting the Simon paradigm was reported by Mohades, Struys, Van Schuerbeek, Baeken, Van De Craen and Luypaert (2014), who compared activation in an event-related design across three groups of children: simultaneous bilinguals, successive early bilinguals, and monolinguals. Mohades et al found significantly higher activity in incongruent trials relative to congruent trials (in response to the increased demand in ignoring the position of stimulus) in both bilingual groups compared to monolinguals in the following brain areas: left superior temporal gyrus, bilateral posterior cingulate gyrus, right middle frontal gyrus, and right caudate nucleus.…”

Data trimming procedure can eliminate bilingual cognitive advantage

“…Some of the studies reviewed were not included into further analysis because there was not adequate information about either the maximum time allowed or how the data was treated (the 3rd study in Bialystok, Martin, et al, 2005, all studies in Gathercole et al, 2014, Yang et al, 2011, and Mohades et al, 2014. Carlson and Meltzoff (2008) was not included either because they did not report RTs.…”