Publications

Abstract

When learning a spoken second language (L2), words overlapping in form and meaning with one’s native language (L1) help break into the new language. When non-signing speakers learn a sign language as L2, such forms are absent because of the modality differences (L1:speech, L2:sign). In such cases, non-signing speakers might use iconic form-meaning mappings in signs or their own gestural experience as gateways into the to-be-acquired sign language. Here, we investigated how both these factors may contribute jointly to the acquisition of sign language vocabulary by hearing non-signers. Participants were presented with three types of sign in NGT (Sign Language of the Netherlands): arbitrary signs, iconic signs with high or low gesture overlap. Signs that were both iconic and highly overlapping with gestures boosted learning most at first exposure, and this effect remained the day after. Findings highlight the influence of modality-specific factors supporting the acquisition of a signed lexicon.

Abstract

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.

Abstract

Bilinguals, by definition, are capable of expressing themselves in more than one language. But which cognitive mechanisms allow them to switch from one language to another? Previous experimental research using the cued language-switching paradigm supports theoretical models that assume that both transient, reactive and sustained, proactive inhibitory mechanisms underlie bilinguals’ capacity to flexibly and efficiently control which language they use. Here we used immersive virtual reality to test the extent to which these inhibitory mechanisms may be active when unbalanced Dutch-English bilinguals i) produce full sentences rather than individual words, ii) to a life-size addressee rather than only into a microphone, iii) using a message that is relevant to that addressee rather than communicatively irrelevant, iv) in a rich visual environment rather than in front of a computer screen. We observed a reversed language dominance paired with switch costs for the L2 but not for the L1 when participants were stand owners in a virtual marketplace and informed their monolingual customers in full sentences about the price of their fruits and vegetables. These findings strongly suggest that the subtle balance between the application of reactive and proactive inhibitory mechanisms that support bilingual language control may be different in the everyday life of a bilingual compared to in the (traditional) psycholinguistic laboratory.

Abstract

Research into bilingual language production has identified a language control network that subserves control operations when bilinguals produce speech. Here we explore which brain areas are recruited for control purposes in bilingual language comprehension. In two experimental fMRI sessions, Dutch-English unbalanced bilinguals read words that differed in cross-linguistic form and meaning overlap across their two languages. The need for control operations was further manipulated by varying stimulus list composition across the two experimental sessions. We observed activation of the language control network in bilingual language comprehension as a function of both cross-linguistic form and meaning overlap and stimulus list composition. These findings suggest that the language control network is shared across bilingual language production and comprehension. We argue that activation of the language control network in language comprehension allows bilinguals to quickly and efficiently grasp the context-relevant meaning of words.

Abstract

This paper introduces virtual reality as an experimental method for the language sciences and provides a review of recent studies using the method to answer fundamental, psycholinguistic research questions. It is argued that virtual reality demonstrates that ecological validity and
experimental control should not be conceived of as two extremes on a continuum, but rather as two orthogonal factors. Benefits of using virtual reality as an experimental method include that in a virtual environment, as in the real world, there is no artificial spatial divide between participant and stimulus. Moreover, virtual reality experiments do not necessarily have to include a repetitive trial structure or an unnatural experimental task. Virtual agents outperform experimental confederates in terms of the consistency and replicability of their behaviour, allowing for reproducible science across participants and research labs. The main promise of virtual reality as a tool for the experimental language sciences, however, is that it shifts theoretical focus towards the interplay between different modalities (e.g., speech, gesture, eye gaze, facial expressions) in dynamic and communicative real-world environments, complementing studies that focus on one modality (e.g. speech) in isolation.

Abstract

Predictive language processing is often studied by measuring eye movements as participants look at objects on a computer screen while they listen to spoken sentences. The use of this variant of the visual world paradigm has shown that information encountered by a listener at a spoken verb can give rise to anticipatory eye movements to a target object, which is taken to indicate that people predict upcoming words. The ecological validity of such findings remains questionable, however, because these computer experiments used two-dimensional (2D) stimuli that are mere abstractions of real world objects. Here we present a visual world paradigm study in a three-dimensional (3D) immersive virtual reality environment. Despite significant changes in the stimulus material and the different mode of stimulus presentation, language-mediated anticipatory eye movements were observed. These findings thus indicate prediction of upcoming words in language comprehension in a more naturalistic setting where natural depth cues are preserved. Moreover, the results confirm the feasibility of using eye-tracking in rich and multimodal 3D virtual environments.

Abstract

The use of immersive virtual reality as a research tool is rapidly increasing in numerous scientific disciplines. By combining ecological validity with strict experimental control, immersive virtual reality provides the potential to develop and test scientific theory in rich environments that closely resemble everyday settings. This article introduces the first standardized database of colored three-dimensional (3D) objects that can be used in virtual reality and augmented reality research and applications. The 147 objects have been normed for name agreement, image agreement, familiarity, visual complexity, and corresponding lexical characteristics of the modal object names. The availability of standardized 3D-objects for virtual reality research is important, as reaching valid theoretical conclusions critically hinges on the use of well controlled experimental stimuli. Sharing standardized 3D-objects across different virtual reality labs will allow for science to move forward more quickly.

Abstract

Bilinguals often switch languages as a function of the language background of their addressee. The control mechanisms supporting bilinguals' ability to select the contextually appropriate language are heavily debated. Here we present four experiments in which unbalanced bilinguals named pictures in their first language Dutch and their second language English in mixed and blocked contexts. Immersive virtual reality technology was used to increase the ecological validity of the cued language-switching paradigm. Behaviorally, we consistently observed symmetrical switch costs, reversed language dominance, and asymmetrical mixing costs. These findings indicate that unbalanced bilinguals apply sustained inhibition to their dominant L1 in mixed language settings. Consequent enhanced processing costs for the L1 in a mixed versus a blocked context were reflected by a sustained positive component in event-related potentials. Methodologically, the use of virtual reality opens up a wide range of possibilities to study language and communication in bilingual and other communicative settings.

Abstract

When we comprehend language, we often do this in rich settings in which we can use many cues to understand what someone is saying. However, it has traditionally been difficult to design experiments with rich three-dimensional contexts that resemble our everyday environments, while maintaining control over the linguistic and non-linguistic information that is available. Here we test the validity of combining electroencephalography (EEG) and Virtual Reality (VR) to overcome this problem. We recorded electrophysiological brain activity during language processing in a well-controlled three-dimensional virtual audiovisual environment. Participants were immersed in a virtual restaurant, while wearing EEG equipment. In the restaurant participants encountered virtual restaurant guests. Each guest was seated at a separate table with an object on it (e.g. a plate with salmon). The restaurant guest would then produce a sentence (e.g. “I just ordered this salmon.”). The noun in the spoken sentence could either match (“salmon”) or mismatch (“pasta”) with the object on the table, creating a situation in which the auditory information was either appropriate or inappropriate in the visual context. We observed a reliable N400 effect as a consequence of the mismatch. This finding validates the combined use of VR and EEG as a tool to study the neurophysiological mechanisms of everyday language comprehension in rich, ecologically valid settings.