Early and Emergent Bilinguals: The Role of Cognitive Control in the Processing of Linguistic Conflict

Abstract

Language processing requires frequent resolution of conflict (e.g. temporary ambiguities, conflicting parsing principles, see Jegerski, 2012). This conflict triggers cognitive control, which has been shown to be a major player in disambiguation among monolinguals (Botvinick, Braver, Barch, Carter & Cohen, 2001; January, Trueswell & Thompson-Schill, 2009). Cognitive control is also a variable of considerable interest in research on early bilingualism and on emergent (second language) bilingualism, as it is responsible for non-active language suppression (Kroll, Dussias, Bogulski, & Valdes Kroff, 2012). For example, many studies reveal cognitive control advantages for early bilinguals in conflict resolution tasks like the flanker task (see Kroll & Bialystok, 2013). Meanwhile, prefrontal brain regions associated with cognitive control are highly active during non-native, non-highly proficient language processing, but that activity diminishes for proficient or native processing (Abutalebi, 2008). However, further research is needed to understand how cognitive control resources are allocated when both disambiguation and non-active language suppression are necessary.

To that end, this dissertation investigated linguistic conflict resolution by early bilinguals and by emergent bilinguals. The participants were 29 Catalan-Spanish early bilinguals (Experiment 1) and 40 L2 Spanish learners at varying proficiency levels (Experiment 2). Following recent research on monolinguals (Hsu & Novick, 2016), the experimental design leveraged the Gratton effect (sustained cognitive control following conflict detection) in order to compare processing speeds after conflictive vs. non-conflictive flanker trials (i.e., in a cognitively neutral vs. engaged state). Mixed-effects models in Experiment 1 showed that subject-object ambiguities presented the same difficulties for early bilinguals that Jegerski (2012) observed of Spanish monolinguals. However, the introduction of cognitive control engagement in the design revealed that ambiguity resolution is faster in the engaged state, in line with Hsu and Novick (2016). In Experiment 2, emergent bilinguals revealed a non-native sentence-final processing effect, indicative of either a delayed garden path or shallow second language processing (cf., Clahsen & Felser, 2006). Nonetheless, this effect was also neutralized when the linguistic conflict was preceded by a conflictive flanker. These two experiments buttress Hsu and Novick’s (2016) finding that dynamic cognitive control engagement facilitates recovery from linguistic conflict.