Cognitive flexibility advantage developing from local switching to global monitoring: effects of task differences and interpreter expertise

Interpreting requires regular and frequent language switching and is thus likely beneficial to cognitive flexibility. However, advantage research found mixed results, probably due to two confounding factors: interpreter expertise and task differences. This study targeted the critical period of intermediate interpreter expertise and compared participants’ switching performance in the rule–based Wisconsin Card Sorting Test (WCST) and the cue-based colour–shape switching tasks (uni-/bivalent versions). Results showed that interpreting students at the pre-intermediate level outperformed bilingual controls in switch cost, and in WCST errors and global RT. With the same participants tested 1 year later and with interpreting students at the post-intermediate level, interpreters outperformed in mixing cost in the bivalent task and in WCST global RT. The findings of the colour–shape switching tasks (further confirmed by cue-based analysis) revealed a developmental transition of interpreters’ advantage from local switching to global monitoring, and a differential sensitivity of the tasks, with implications for studies on bilingual advantage.