Julia Hofweber (University of Reading)
bilingualism and cognition; executive control functions; code-switching; bilingualism and mental flexibility
This poster explores the question how code-switching (CS) modulates executive functions. Bilinguals’ inhibitory advantages are attributed to frequent practice at suppressing co-activated non-target varieties in monolingual contexts. CS however allows co-activated varieties to reach articulatory stages raising the question to which extent inhibition is recruited. The flipside of not inhibiting languages is practice at task-switching as the co-activated varieties need to be managed (Green & Wei, 2014). Three types of CS varying in degree of L1-L2 co-activation and resulting inhibitory control and task-switching involvement have been described (Muysken, 2000): alternation (L1-L2 phrase juxtaposition involving little co-activation), insertion (L2 constituents embedded in L1 structure with co-activation of lexical schemata), dense CS (co-activation of grammatical, lexical and semantic schemata). The emergence of these patterns depends on speakers’ language history and dominance profiles. The linguistic characteristics of the three types of CS lead to the prediction that late bilingual L2-users are more likely to use their dominant L1 as the matrix language fostering insertional code-switching. Heritage speakers in established bilingual communities may mix languages more densely.
This study measured executive functions amongst two groups of German-English bilinguals with different CS profiles: German L2-users of English engaging predominantly in insertional CS and German heritage speakers in South Africa with a greater preference for dense CS. The independent factor CS preference is treated as a continuous variable to capture individual variation using multiple methods: questionnaires creating scores for CS frequency, intentionality, type and attitude, elicited and authentic emails tapping into free production, acceptability judgement and sentence repetition tasks indicating cognitive embedding. The dependent variable executive control performance is tested using flanker tasks. Tasks are arranged into blocks varying in degree of task-switching thus generating not only a conflict effect measuring inhibition, but also a mixing cost measuring mental flexibility (Costa et al., 2009). As dense CS recruits and enhances inhibition least and task-switching most, increased preference for dense CS is predicted to correlate positively with conflict effect and negatively with mixing cost. Moreover, bilinguals are predicted to outperform monolinguals in conditions requiring greater mental flexibility. Indeed preliminary pilot study results reveal the most salient bilingual conflict effect advantages in blocks challenging mental flexibility most. Scores from the acceptability judgement display a negative relationship with mixing cost for all CS types, but this correlation only reaches significance for dense CS (r = – 0.56; p < 0.05). This indicates that mental flexibility is enhanced most by the type of CS involving linguistic co-activation at multiple levels.
 Costa, A., Hernandez, M., Costa-Faidella, J., Sebastian-Galles, N. On the bilingual advantage in conflict processing: Now you see it, now you don’t. Cognition, 113:135-149, 2009.
 Green, D.W., Wei, L. A control process model of CS. Language, Cognition and Neuroscience, 24(9):499-511, 2009.
 Muysken, P. Bilingual Speech: A Typology of Code-mixing. Cambridge: Cambridge University Press, 2000.