Are simultaneous interpreters subject to the central processing bottleneck during language production?

Simultaneous interpreting (SI), the mode of interpreting generally used at international conferences, is an exceptionally complex language-processing task, which requires interpreters to continuously receive source language (SL) utterances, store the information in memory, transcode utterances into the target language (TL), and articulate the previous segments. What makes SI particularly difficult to perform is that all the above processes are carried out in real time. Almost all models of cognitive processing during SI share the assumption that cognitive resources are limited and shared by all the components of processing that need to occur concurrently (Gerver, 1976; Gile, 1997; Liu et al., 2004; Christoffels & De Groot, 2004; Padilla, Bajo & Macizo, 2005). This assumption has gone largely unchallenged, and yet psycholinguistic research on language performance has suggested that language production is subject to a central processing bottleneck (Welford, 1952) which allows only one task to be performed at a time. This raises the as-yet-unanswered question of whether interpreters, despite their professional experience, are also subject to the central processing bottleneck during language production, or whether interpreters’ extensive experience leads to more efficient lemma and phonological word-form selection than is the case for bilinguals and monolinguals, alleviating the bottleneck. In this study, I investigate these questions using an experiment in the dual-task paradigm. The results suggest that even language experts such as simultaneous interpreters are subject to the central processing bottleneck during word production. No significant difference was found between the three matched groups of professional interpreters, bilinguals and monolinguals on the duration of the bottleneck stage during word production. In addition, the results indicate that interpreters are as good at anticipating the upcoming word as monolinguals, and better than proficient bilinguals.