Discussion

We investigated the time-course of prediction during a simultaneous interpreting task in professional simultaneous interpreters and professional translators untrained in interpreting. L1 French professional simultaneous interpreters listened to English sentences containing a highly predictable word and simultaneously interpreted these sentences into French. L1 French professional translators were tested under the same conditions. The results showed that both professional simultaneous interpreters and professional

translators predict upcoming information while simultaneously interpreting. Simultaneous interpreters made predictions earlier than translators (see the linear-mixed model analyses

by group), and they also showed a greater number of fixations on the target object relative to the unrelated object (see the growth curve analysis). In an exploratory analysis, we found that participants whose comprehension and production were more synchronized predicted to a greater extent than those who lagged further behind the original.

3.5.1 Evidence for prediction during simultaneous interpreting

The current findings show that both professional simultaneous interpreters and professional translators, untrained in simultaneous interpreting, make predictive eye movements during a simultaneous interpreting task. This evidence supports theories of simultaneous interpreting which assume that prediction takes place during simultaneous interpreting (e.g., Chernov, 2004; Seleskovitch, 1984).

The current findings also show robust prediction in L2 speakers listening to their L2, who are completing an additional task. This contrasts with current findings. For example, Ito et al. (2017) found that L2 listeners did not make predictive eye movements before target word onset when they had an additional cognitive load. In contrast, our experiment found that even when resources are used for simultaneous interpreting, highly proficient bilinguals still make predictive eye movements.

Now let us compare our experiment with Experiments 1 and 2 of Ito et al. (2018) The professional simultaneous interpreters (L2 speakers) in our study made predictive eye movements earlier than the L2 speakers in Experiment 2 of Ito et al.’s 2018 study. In their timing, the predictive fixations on target objects made by simultaneous interpreters in our study were more similar to the predictive fixations made by L1 speakers in Experiment 1 of Ito et al. (2018) (with predictive fixations in both of these experiments beginning at -600ms before onset of a predictable word). However, unlike the L1 speakers in Ito et al. (2018),

interpreters did not fixate on English competitor objects significantly more than on unrelated objects during the predictive time window. The results suggest that during a simultaneous interpreting task, interpreters predict predictable words, but may not pre-activate their phonological form.

3.5.2 Simultaneous interpreters predict more than translators

Although both simultaneous interpreters and translators predicted during our simultaneous interpreting task, we found differences in their patterns of prediction.

Simultaneous interpreters made earlier predictive eye movements than translators –

predictive eye movements in the interpreter group began 200ms earlier than predictive eye movements in the translator group. In addition, interpreters made more predictive fixations on target objects compared to unrelated objects than translators. The growth curve analysis revealed that differences between fixations on target objects and unrelated objects were smaller for the translator group. Since the translators in our study were very evenly

matched with the interpreters in terms of proficiency in French and in English, in age and in education, we suggest that the difference between participant groups was due to the fact that translators do not have experience in carrying out a simultaneous interpreting task.

This in turn suggests either 1) that interpreters possess some skill which allows them to make earlier predictions than translators, 2) that interpreters could have automated other parts of the simultaneous interpreting task, freeing up cognitive resources for predictive processing, or 3) that interpreters purposefully devote cognitive resources to prediction because it helps them carry out the task of simultaneous interpreting (or a combination of these).

3.5.3 Prediction of word-form during simultaneous interpreting

We did not find any evidence of prediction of word form in English by either the translator or the interpreter group during the simultaneous interpreting task. However, there was evidence that word form was activated in the interpreter group after onset of the target word, showing that hearing the target word activated its phonological competitors.

This contrasts with Ito et al. (2018) who found phonological prediction, in the absence of an interpreting task (see also Kukona, 2020). Therefore, it may be that, as in Martin, Branzi and Bar (2018), simultaneous interpreting limited prediction by engaging the production

mechanism. The simultaneous interpreting task may also have limited eye movements linked to linguistic activation due to the attendant working memory load (for example, see Prasad & Mishra, 2020). Alternatively, it may be because even highly proficient L2 speakers do not predictively activate word form during comprehension, even when their two

languages share the same script.

Further, despite engaging in a simultaneous interpreting task into French, there was no evidence that professional translators or interpreters activated the French form of the target word. This replicates Ito et al. (2018) who showed that Japanese participants did not activate the phonology of the Japanese translation of the target word.

3.5.4 Exploratory findings suggest that lag and prediction are linked In an exploratory analysis, we found that when production was more closely synchronised with comprehension (i.e., when interpretation began earlier relative to the target word), participants began to make predictive eye movements earlier than when production and comprehension were less synchronized. In addition, when production and comprehension were more synchronized, an exploratory analysis suggested that

participants appeared to activate the phonological form of the upcoming word predictively.

On the one hand, when participants predict more, they may produce their own utterance more quickly thanks to this prediction allowing participants to maintain a shorter lag between comprehension and production. On the other hand, following a prediction-by-production account, it may be the greater synchronicity between prediction-by-production and

comprehension that allows greater prediction. In other words, if participants' own utterances are more synchronized with the utterances that they comprehend, predictive processing might be supported, whereas if participants’ own utterances are less

synchronized with what they comprehend, this might be more akin to engaging the production mechanism in an unrelated task as in Martin, Branzi and Bar (2018). However, this is an exploratory analysis whose results we must interpret with caution, as some of the counterbalancing present in the experiment is invalidated when such an exploratory

analysis is conducted.

3.6 Conclusion

We reported an experiment that investigated whether professional interpreters and professional translators make predictive eye movements during a simultaneous interpreting task. We found that professional interpreters made more predictive eye movements than professional translators, but that neither group pre-activated phonological information associated with a target word. Thus, prediction takes place during simultaneous

interpreting, but the precision of this prediction remains unclear.

4 STUDY 2. DO INTERPRETERS LEARN TO PREDICT DIFFERENTLY