The effect of bilingualism on perceptual processing in adults

The experience of language can, as any other experience, change the way that the human brain is organized and connected. Fluency in more than one language should, in turn, change the brain in the same way. Recent research has focused on the differences in processing between bilinguals and monolinguals, and has even ventured into using different neuroimaging techniques to study why these differences exist. What previous research has failed to identify is the mechanism that is responsible for the difference in processing. In an attempt to gather information about these effects, this study explores the possibility that bilingual individuals utilize lower signal strength (and by comparison less biological energy) to complete the same tasks that monolingual individuals do. Using an electroencephalograph (EEG), signal strength is retrieved during two perceptual tasks, the Landolt C and the critical flicker fusion threshold, as well as one executive task (the Stroop task). Most likely due to small sample size, bilingual participants did not perform better than monolingual participants on any of the tasks they were given, but they did show a lower EEG signal strength during the Landolt C task than monolingual participants. Monolingual participants showed a lower EEG signal strength during the Stroop task, which stands to support the idea that a linguistic processing task adds complexity to the bilingual brain. Likewise, analysis revealed a significantly lower signal strength during the critical flicker fusion task for monolingual participants than for bilingual participants. Monolingual participants also had a significantly different variability during the critical flicker fusion threshold task, suggesting that becoming bilingual creates an entirely separate population of individuals. Future research should perform analysis with the addition of a prefrontal cortex electrode to determine if less collaboration during processing is present for bilinguals, and if signal complexity in the prefrontal cortex is lower than other electrodes.