Publications

Abstract

Beat gestures—spontaneously produced biphasic movements of the hand—
are among the most frequently encountered co-speech gestures in human
communication. They are closely temporally aligned to the prosodic charac-
teristics of the speech signal, typically occurring on lexically stressed
syllables. Despite their prevalence across speakers of the world’s languages,
how beat gestures impact spoken word recognition is unclear. Can these
simple ‘flicks of the hand’ influence speech perception? Across a range
of experiments, we demonstrate that beat gestures influence the explicit
and implicit perception of lexical stress (e.g. distinguishing OBject from
obJECT), and in turn can influence what vowels listeners hear. Thus, we pro-
vide converging evidence for a manual McGurk effect: relatively simple and
widely occurring hand movements influence which speech sounds we hear

Abstract

The ability to predict upcoming actions is a hallmark of cognition. It remains unclear, however, whether the predictive behaviour observed in controlled lab environments generalises to rich, everyday settings. In four virtual reality experiments, we tested whether a well-established marker of linguistic prediction (anticipatory eye movements) replicated when increasing the naturalness of the paradigm by means of immersing participants in naturalistic scenes (Experiment 1), increasing the number of distractor objects (Experiment 2), modifying the proportion of predictable noun-referents (Experiment 3), and manipulating the location of referents relative to the joint attentional space (Experiment 4). Robust anticipatory eye movements were observed for Experiments 1–3. The anticipatory effect disappeared, however, in Experiment 4. Our findings suggest that predictive processing occurs in everyday communication if the referents are situated in the joint attentional space. Methodologically, our study confirms that ecological validity and experimental control may go hand-in-hand in the study of human predictive behaviour.

Abstract

In all spoken languages, speakers use demonstratives – words like this and that – to refer to entities in their immediate environment. But which factors determine whether they use one demonstrative (this) or another (that)? Here we report the results of an experiment examining the effects of referent visibility, referent distance, and addressee location on the production of demonstratives by speakers of Ticuna (isolate; Brazil, Colombia, Peru), an Amazonian language with four demonstratives, and speakers of Dutch (Indo-European; Netherlands, Belgium), which has two demonstratives. We found that Ticuna speakers’ use of demonstratives displayed effects of addressee location and referent distance, but not referent visibility. By contrast, under comparable conditions, Dutch speakers displayed sensitivity only to referent distance. Interestingly, we also observed that Ticuna speakers consistently used demonstratives in all referential utterances in our experimental paradigm, while Dutch speakers strongly preferred to use definite articles. Taken together, these findings shed light on the significant diversity found in demonstrative systems across languages. Additionally, they invite researchers studying exophoric demonstratives to broaden their horizons by cross-linguistically investigating the factors involved in speakers’ choice of demonstratives over other types of referring expressions, especially articles.

Abstract

Language allows us to efficiently communicate about the things in the world around us. Seemingly simple words like this and that are a cornerstone of our capability to refer, as they contribute to guiding the attention of our addressee to the specific entity we are talking about. Such demonstratives are acquired early in life, ubiquitous in everyday talk, often closely tied to our gestural communicative abilities, and present in all spoken languages of the world. Based on a review of recent experimental work, we here introduce a new conceptual framework of demonstrative reference. In the context of this framework, we argue that several physical, psychological, and referent-intrinsic factors dynamically interact to influence whether a speaker will use one demonstrative form (e.g., this) or another (e.g., that) in a given setting. However, the relative influence of these factors themselves is argued to be a function of the cultural language setting at hand, the theory-of-mind capacities of the speaker, and the affordances of the specific context in which the speech event takes place. It is demonstrated that the framework has the potential to reconcile findings in the literature that previously seemed irreconcilable. We show that the framework may to a large extent generalize to instances of endophoric reference (e.g., anaphora) and speculate that it may also describe the specific form and kinematics a speaker’s pointing gesture takes. Testable predictions and novel research questions derived from the framework are presented and discussed.

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.

Abstract

Wanneer iemand goed is in het spreken van meerdere talen, wordt wel gezegd dat zo iemand een talenknobbel heeft. Iedereen weet dat dat niet letterlijk bedoeld is: iemand met een talenknobbel herkennen we niet aan een grote bult op zijn hoofd. Toch dacht men vroeger wel degelijk dat mensen een letterlijke talenknobbel konden ontwikkelen. Een goed ontwikkeld taalvermogen zou gepaard gaan met het groeien van het hersengebied dat hiervoor verantwoordelijk was. Dit deel van het brein zou zelfs zo groot kunnen worden dat het van binnenuit tegen de schedel drukte, met name rond de ogen. Nu weten we wel beter. Maar waar in het brein bevindt de taal zich dan wel precies?