What's your point? Insights from virtual reality on the relation between intention and action in the production of pointing gestures

Beyond the tried and true: How virtual reality, dialog setups, and a focus on multimodality can take bilingual language production research forward

Bilinguals possess the ability of expressing themselves in more than one language, and typically do so in contextually rich and dynamic settings. Theories and models have indeed long considered context factors to affect bilingual language production in many ways. However, most experimental studies in this domain have failed to fully incorporate linguistic, social, or physical context aspects, let alone combine them in the same study. Indeed, most experimental psycholinguistic research has taken place in isolated and constrained lab settings with carefully selected words or sentences, rather than under rich and naturalistic conditions. We argue that the most influential experimental paradigms in the psycholinguistic study of bilingual language production fall short of capturing the effects of context on language processing and control presupposed by prominent models. This paper therefore aims to enrich the methodological basis for investigating context aspects in current experimental paradigms and thereby move the field of bilingual language production research forward theoretically. After considering extensions of existing paradigms proposed to address context effects, we present three far-ranging innovative proposals, focusing on virtual reality, dialog situations, and multimodality in the context of bilingual language production.

Combining EEG and 3D-eye-tracking to study the prediction of upcoming speech in naturalistic virtual environments: A proof of principle

EEG and eye-tracking provide complementary information when investigating language comprehension. Evidence that speech processing may be facilitated by speech prediction comes from the observation that a listener's eye gaze moves towards a referent before it is mentioned if the remainder of the spoken sentence is predictable. However, changes to the trajectory of anticipatory fixations could result from a change in prediction or an attention shift. Conversely, N400 amplitudes and concurrent spectral power provide information about the ease of word processing the moment the word is perceived. In a proof-of-principle investigation, we combined EEG and eye-tracking to study linguistic prediction in naturalistic, virtual environments. We observed increased processing, reflected in theta band power, either during verb processing - when the verb was predictive of the noun - or during noun processing - when the verb was not predictive of the noun. Alpha power was higher in response to the predictive verb and unpredictable nouns. We replicated typical effects of noun congruence but not predictability on the N400 in response to the noun. Thus, the rich visual context that accompanied speech in virtual reality influenced language processing compared to previous reports, where the visual context may have facilitated processing of unpredictable nouns. Finally, anticipatory fixations were predictive of spectral power during noun processing and the length of time fixating the target could be predicted by spectral power at verb onset, conditional on the object having been fixated. Overall, we show that combining EEG and eye-tracking provides a promising new method to answer novel research questions about the prediction of upcoming linguistic input, for example, regarding the role of extralinguistic cues in prediction during language comprehension.