Publications

Abstract

This paper investigates whether there are changes in gesture rate when speakers of two languages with different gesture rates (Turkish-high gesture; Dutch-low gesture) come into daily contact. We analyzed gestures produced by second-generation heritage speakers of Turkish in the Netherlands in each language, comparing them to monolingual baselines. We did not find differences between bilingual and monolingual speakers, possibly because bilinguals were proficient in both languages and used them frequently – in line with a usage-based approach to language. However, bilinguals produced more deictic gestures than monolinguals in both Turkish and Dutch, which we interpret as a bilingual strategy. Deictic gestures may help organize discourse by placing entities in gesture space and help reduce the cognitive load associated with being bilingual, e.g., inhibition cost. Therefore, gesture rate does not necessarily change in contact situations but might be modulated by frequency of language use, proficiency, and cognitive factors related to being bilingual.

Abstract

Aim:

This paper examines whether second-generation Turkish heritage speakers in the Netherlands follow language-specific patterns of reference tracking in Turkish and Dutch, focusing on discourse status and pragmatic contexts as factors that may modulate the choice of referring expressions (REs), that is, the noun phrase (NP), overt pronoun and null pronoun.
Methodology:

Two short silent videos were used to elicit narratives from 20 heritage speakers of Turkish, both in Turkish and in Dutch. Monolingual baseline data were collected from 20 monolingually raised speakers of Turkish in Turkey and 20 monolingually raised speakers of Dutch in the Netherlands. We also collected language background data from bilinguals with an extensive survey.
Data and analysis:

Using generalised logistic mixed-effect regression, we analysed the influence of discourse status and pragmatic context on the choice of subject REs in Turkish and Dutch, comparing bilingual data to the monolingual baseline in each language.
Findings:

Heritage speakers used overt versus null pronouns in Turkish and stressed versus reduced pronouns in Dutch in pragmatically appropriate contexts. There was, however, a slight increase in the proportions of overt pronouns as opposed to NPs in Turkish and as opposed to null pronouns in Dutch. We suggest an explanation based on the degree of entrenchment of differential RE types in relation to discourse status as the possible source of the increase.
Originality:

This paper provides data from an understudied language pair in the domain of reference tracking in language contact situations. Unlike several studies of pronouns in language contact, we do not find differences across monolingual and bilingual speakers with regard to pragmatic constraints on overt pronouns in the minority pro-drop language.
Significance:

Our findings highlight the importance of taking language proficiency and use into account while studying bilingualism and combining formal approaches to language use with usage-based approaches for a more complete understanding of bilingual language production.

Abstract

In individuals with synaesthesia specific sensory stimulation leads to unusual concurrent perceptions in the same or a different modality. Recent studies have demonstrated a high co-occurrence between synaesthesia and autism spectrum disorder (ASD), a condition also characterized by altered perception. A potentially shared characteristic of synaesthesia and ASD is a bias towards local (detail-focussed) perception. We investigated whether a bias towards local perception is indeed shared between synaesthesia and ASD. In a neurotypical population, we studied the relation between the degree of autistic traits (measured by the AQ) and the degree of grapheme-colour synaesthesia (measured by a consistency task), as well as whether both are related to a local bias in tasks assessing local/global visual perception. A positive correlation between total AQ scores and the degree of synaesthesia was found. Our study extends previous studies that found a high ASD-synaesthesia co-occurrence in clinical populations. Consistent with the hypothesized local perceptual bias in ASD, scores on the AQ-attention to detail subscale were related to increased performance on an Embedded Figures Task (EFT), and we found evidence for a relation to reduced susceptibility to visual illusions. We found no relation between autistic traits and local visual perception in a motion coherence task (MCT). Also, no relation between synaesthesia and local visual perception was found, although a reduced susceptibility to visual illusions resembled the results obtained for AQ-atttention to detail subscale. A suggested explanation for the absence of a relationship between the degree of synaesthesia and a local bias is that a possible local bias might be more pronounced in supra-threshold synaesthetes (compared to neurotypicals).

Abstract

While speculations on form–meaning resemblances in language go back millennia, the experimental study of iconicity is only about a century old. Here we take stock of experimental work on iconicity and present a double special issue with a diverse set of new contributions. We contextualise the work by introducing a typology of approaches to iconicity in language. Some approaches construe iconicity as a discrete property that is either present or absent; others treat it as involving semiotic relationships that come in kinds; and yet others see it as a gradient substance that comes in degrees. We show the benefits and limitations that come with each of these construals and stress the importance of developing accounts that can fluently switch between them. With operationalisations of iconicity that are well defined yet flexible enough to deal with differences in tasks, modalities, and levels of analysis, experimental research on iconicity is well equipped to contribute to a comprehensive science of language.

Abstract

Resource-rational approaches offer much promise for understanding human cognition, especially if they can reach beyond the confines of individual minds. Language allows people to transcend individual resource limitations by augmenting computation and enabling distributed cognition. Interactive language use, an environment where social rational agents routinely deal with resource constraints together, offers a natural laboratory to test resource-rationality in the wild.

Abstract

Aktuelle Vorstellungen von Gehirn-zu-Gehirn-Schnittstellen versprechen, die Sprache zu umgehen. Aber wenn wir sie verfeinern, um ihr kollaboratives Potenzial voll auszuschöpfen, sehen wir Sprache — oder zumindest ein sprachähnliches Infrastruktur für Kommunika­tion und Koordination — durch die Hintertür wieder hereinkommen. Es wäre nicht das erste Mal, dass sich die Sprache neu erfindet.

Current conceptions of brain-to-brain interfaces attempt to bypass language. But when we refine them to more fully realise their collaborative potential we find language —or at least a language-like infrastructure for communication and coordination— slipping through the back door. It wouldn't be the first time that language reinvented itself.

Abstract

Words like ‘waddle’, ‘flop’ and ‘zigzag’ combine playful connotations with iconic form-meaning resemblances. Here we propose that structural markedness may be a common factor underlying perceptions of playfulness and iconicity. Using collected and estimated lexical ratings covering a total of over 70,000 English words, we assess the robustness of this assocation. We identify cues of phonotactic complexity that covary with funniness and iconicity ratings and that, we propose, serve as metacommunicative signals to draw attention to words as playful and performative. To assess the generalisability of the findings we develop a method to estimate lexical ratings from distributional semantics and apply it to a dataset 20 times the size of the original set of human ratings. The method can be used more generally to extend coverage of lexical ratings. We find that it reliably reproduces correlations between funniness and iconicity as well as cues of structural markedness, though it also amplifies biases present in the human ratings. Our study shows that the playful and the poetic are part of the very texture of the lexicon.

Abstract

Most objects have well-defined affordances. Investigating perception of affordances of objects that were not created for a specific purpose would provide insight into how affordances are perceived. In addition, comparison of perception of affordances for such objects across different exploratory modalities (visual vs. haptic) would offer a strong test of the lawfulness of information about affordances (i.e., the invariance of such information over transformation). Along these lines, “feelies”— objects created by Gibson with no obvious function and unlike any common object—could shed light on the processes underlying affordance perception. This study showed that when observers reported potential uses for feelies, modality significantly influenced what kind of affordances were perceived. Specifically, visual exploration resulted in more noun labels (e.g., “toy”) than haptic exploration which resulted in more verb labels (i.e., “throw”). These results suggested that overlapping, but distinct classes of action possibilities are perceivable using vision and haptics. Semantic network analyses revealed that visual exploration resulted in object-oriented responses focused on object identification, whereas haptic exploration resulted in action-oriented responses. Cluster analyses confirmed these results. Affordance labels produced in the visual condition were more consistent, used fewer descriptors, were less diverse, but more novel than in the haptic condition.

Abstract

Native listeners benefit from both visible speech and iconic gestures to enhance degraded speech comprehension (Drijvers & Ozyürek, 2017). We tested how highly proficient non-native listeners benefit from these visual articulators compared to native listeners. We presented videos of an actress uttering a verb in clear, moderately, or severely degraded speech, while her lips were blurred, visible, or visible and accompanied by a gesture. Our results revealed that unlike native listeners, non-native listeners were less likely to benefit from the combined enhancement of visible speech and gestures, especially since the benefit from visible speech was minimal when the signal quality was not sufficient.

Abstract

During silent problem solving, hand gestures arise that have no communicative intent. The role of such co-thought gestures in
cognition has been understudied in cognitive research as compared to co-speech gestures. We investigated whether gesticulation
during silent problem solving supported subsequent performance in a Tower of Hanoi problem-solving task, in relation
to visual working-memory capacity and task complexity. Seventy-six participants were assigned to either an instructed gesture
condition or a condition that allowed them to gesture, but without explicit instructions to do so. This resulted in three
gesture groups: (1) non-gesturing; (2) spontaneous gesturing; (3) instructed gesturing. In line with the embedded/extended
cognition perspective on gesture, gesturing benefited complex problem-solving performance for participants with a lower
visual working-memory capacity, but not for participants with a lower spatial working-memory capacity.

Abstract

Speakers often use gesture to demonstrate how to perform actions—for example, they might show how to open the top of a jar by making a twisting motion above the jar. Yet it is unclear whether listeners learn as much from seeing such gestures as they learn from seeing actions that physically change the position of objects (i.e., actually opening the jar). Here, we examined participants' implicit and explicit understanding about a series of movements that demonstrated how to move a set of objects. The movements were either shown with actions that physically relocated each object or with gestures that represented the relocation without touching the objects. Further, the end location that was indicated for each object covaried with whether the object was grasped with one or two hands. We found that memory for the end location of each object was better after seeing the physical relocation of the objects, that is, after seeing action, than after seeing gesture, regardless of whether speech was absent (Experiment 1) or present (Experiment 2). However, gesture and action built similar implicit understanding of how a particular handgrasp corresponded with a particular end location. Although gestures miss the benefit of showing the end state of objects that have been acted upon, the data show that gestures are as good as action in building knowledge of how to perform an action.

Abstract

This article makes the case for the universality of the sequence organization observable in informal human conversational interaction. Using the descriptive schema developed by Schegloff (2007), we examine the major patterns of action-sequencing in a dozen nearly all unrelated languages. What we find is that these patterns are instantiated in very similar ways for the most part right down to the types of different action sequences. There are also some notably different cultural exploitations of the patterns, but the patterns themselves look strongly universal. Recent work in gestural communication in the great apes suggests that sequence organization may have been a crucial route into the development of language. Taken together with the fundamental role of this organization in language acquisition, sequential behavior of this kind seems to have both phylogenetic and ontogenetic priority, which probably puts substantial functional pressure on language form.

Abstract

Face-to-face communication is multimodal at its core: it consists of a combination of vocal and visual signalling. However, current evidence suggests that, in the absence of an established communication system, visual signalling, especially in the form of visible gesture, is a more powerful form of communication than vocalisation, and therefore likely to have played a primary role in the emergence of human language. This argument is based on experimental evidence of how vocal and visual modalities (i.e., gesture) are employed to communicate about familiar concepts when participants cannot use their existing languages. To investigate this further, we introduce an experiment where pairs of participants performed a referential communication task in which they described unfamiliar stimuli in order to reduce reliance on conventional signals. Visual and auditory stimuli were described in three conditions: using visible gestures only, using non-linguistic vocalisations only and given the option to use both (multimodal communication). The results suggest that even in the absence of conventional signals, gesture is a more powerful mode of communication compared to vocalisation, but that there are also advantages to multimodality compared to using gesture alone. Participants with an option to produce multimodal signals had comparable accuracy to those using only gesture, but gained an efficiency advantage. The analysis of the interactions between participants showed that interactants developed novel communication systems for unfamiliar stimuli by deploying different modalities flexibly to suit their needs and by taking advantage of multimodality when required.

Abstract

To talk about space, spoken languages rely on arbitrary and categorical forms (e.g., left, right). In sign languages, however, the visual–spatial modality allows for iconic encodings (motivated form-meaning mappings) of space in which form and location of the hands bear resemblance to the objects and spatial relations depicted. We assessed whether the iconic encodings in sign languages guide visual attention to spatial relations differently than spatial encodings in spoken languages during message preparation at the sentence level. Using a visual world production eye-tracking paradigm, we compared 20 deaf native signers of Sign-Language-of-the-Netherlands and 20 Dutch speakers’ visual attention to describe left versus right configurations of objects (e.g., “pen is to the left/right of cup”). Participants viewed 4-picture displays in which each picture contained the same 2 objects but in different spatial relations (lateral [left/right], sagittal [front/behind], topological [in/on]) to each other. They described the target picture (left/right) highlighted by an arrow. During message preparation, signers, but not speakers, experienced increasing eye-gaze competition from other spatial configurations. This effect was absent during picture viewing prior to message preparation of relational encoding. Moreover, signers’ visual attention to lateral and/or sagittal relations was predicted by the type of iconicity (i.e., object and space resemblance vs. space resemblance only) in their spatial descriptions. Findings are discussed in relation to how “thinking for speaking” differs from “thinking for signing” and how iconicity can mediate the link between language and human experience and guides signers’ but not speakers’ attention to visual aspects of the world.

Abstract

When learning a second spoken language, cognates, words overlapping in form and meaning with one’s native language, help breaking into the language one wishes to acquire. But what happens when the to-be-acquired second language is a sign language? We tested whether hearing nonsigners rely on their gestural repertoire at first exposure to a sign language. Participants saw iconic signs with high and low overlap with the form of iconic gestures while electrophysiological brain activity was recorded. Upon first exposure, signs with low overlap with gestures elicited enhanced positive amplitude in the P3a component compared to signs with high overlap. This effect disappeared after a training session. We conclude that nonsigners generate expectations about the form of iconic signs never seen before based on their implicit knowledge of gestures, even without having to produce them. Learners thus draw from any available semiotic resources when acquiring a second language, and not only from their linguistic experience

Abstract

An unprecedented number of empirical studies have shown that iconic gestures—those that mimic the sensorimotor attributes of a referent—contribute significantly to language acquisition, perception, and processing. However, there has been a lack of normed studies describing generalizable principles in gesture production and in comprehension of the mappings of different types of iconic strategies (i.e., modes of representation; Müller, 2013). In Study 1 we elicited silent gestures in order to explore the implementation of different types of iconic representation (i.e., acting, representing, drawing, and personification) to express concepts across five semantic domains. In Study 2 we investigated the degree of meaning transparency (i.e., iconicity ratings) of the gestures elicited in Study 1. We found systematicity in the gestural forms of 109 concepts across all participants, with different types of iconicity aligning with specific semantic domains: Acting was favored for actions and manipulable objects, drawing for nonmanipulable objects, and personification for animate entities. Interpretation of gesture–meaning transparency was modulated by the interaction between mode of representation and semantic domain, with some couplings being more transparent than others: Acting yielded higher ratings for actions, representing for object-related concepts, personification for animate entities, and drawing for nonmanipulable entities. This study provides mapping principles that may extend to all forms of manual communication (gesture and sign). This database includes a list of the most systematic silent gestures in the group of participants, a notation of the form of each gesture based on four features (hand configuration, orientation, placement, and movement), each gesture’s mode of representation, iconicity ratings, and professionally filmed videos that can be used for experimental and clinical endeavors.

Abstract

In this study we explore whether different types of iconic gestures
(i.e., acting, drawing, representing) and their combinations are used
systematically to distinguish between different semantic categories in
production and comprehension. In Study 1, we elicited silent gestures
from Mexican and Dutch participants to represent concepts from three
semantic categories: actions, manipulable objects, and non-manipulable
objects. Both groups favoured the acting strategy to represent actions and
manipulable objects; while non-manipulable objects were represented
through the drawing strategy. Actions elicited primarily single gestures
whereas objects elicited combinations of different types of iconic gestures
as well as pointing. In Study 2, a different group of participants were
shown gestures from Study 1 and were asked to guess their meaning.
Single-gesture depictions for actions were more accurately guessed than
for objects. Objects represented through two-gesture combinations (e.g.,
acting + drawing) were more accurately guessed than objects represented
with a single gesture. We suggest iconicity is exploited to make direct
links with a referent, but when it lends itself to ambiguity, individuals
resort to combinatorial structures to clarify the intended referent.
Iconicity and the need to communicate a clear signal shape the structure
of silent gestures and this in turn supports comprehension.

Abstract

We show that the human voice has complex acoustic qualities that are directly coupled to peripheral musculoskeletal tensioning of the body, such as subtle wrist movements. In this study, human vocalizers produced a steady-state vocalization while rhythmically moving the wrist or the arm at different tempos. Although listeners could only hear but not see the vocalizer, they were able to completely synchronize their own rhythmic wrist or arm movement with the movement of the vocalizer which they perceived in the voice acoustics. This study corroborates
recent evidence suggesting that the human voice is constrained by bodily tensioning affecting the respiratory-vocal system. The current results show that the human voice contains a bodily imprint that is directly informative for the interpersonal perception of another’s dynamic physical states.

Abstract

Expressive moments in communicative hand gestures often align with emphatic stress in speech. It has recently been found that acoustic markers of emphatic stress arise naturally during steady-state phonation when upper-limb movements impart physical impulses on the body, most likely affecting acoustics via respiratory activity. In this confirmatory study, participants (N = 29) repeatedly uttered consonant-vowel (/pa/) mono-syllables while moving in particular phase relations with speech, or not moving the upper limbs. This study shows that respiration-related activity is affected by (especially high-impulse) gesturing when vocalizations occur near peaks in physical impulse. This study further shows that gesture-induced moments of bodily impulses increase the amplitude envelope of speech, while not similarly affecting the Fundamental Frequency (F0). Finally, tight relations between respiration-related activity and vocalization were observed, even in the absence of movement, but even more so when upper-limb movement is present. The current findings expand a developing line of research showing that speech is modulated by functional biomechanical linkages between hand gestures and the respiratory system. This identification of gesture-speech biomechanics promises to provide an alternative phylogenetic, ontogenetic, and mechanistic explanatory route of why communicative upper limb movements co-occur with speech in humans.
ACKNOWLEDGMENTS

Abstract

We introduce applications of established methods in time-series and network
analysis that we jointly apply here for the kinematic study of gesture
ensembles. We define a gesture ensemble as the set of gestures produced
during discourse by a single person or a group of persons. Here we are
interested in how gestures kinematically relate to one another. We use
a bivariate time-series analysis called dynamic time warping to assess how
similar each gesture is to other gestures in the ensemble in terms of their
velocity profiles (as well as studying multivariate cases with gesture velocity
and speech amplitude envelope profiles). By relating each gesture event to
all other gesture events produced in the ensemble, we obtain a weighted
matrix that essentially represents a network of similarity relationships. We
can therefore apply network analysis that can gauge, for example, how
diverse or coherent certain gestures are with respect to the gesture ensemble.
We believe these analyses promise to be of great value for gesture
studies, as we can come to understand how low-level gesture features
(kinematics of gesture) relate to the higher-order organizational structures
present at the level of discourse.

Abstract

When people are engaged in social interaction, they can repeat aspects of each other’s communicative behavior, such as words or gestures. This kind of behavioral alignment has been studied across a wide range of disciplines and has been accounted for by diverging theories. In this paper, we review various operationalizations of lexical and gestural alignment. We reveal that scholars have fundamentally different takes on when and how behavior is considered to be aligned, which makes it difficult to compare findings and draw uniform conclusions. Furthermore, we show that scholars tend to focus on one particular dimension of alignment (traditionally, whether two instances of behavior overlap in form), while other dimensions remain understudied. This hampers theory testing and building, which requires a well‐defined account of the factors that are central to or might enhance alignment. To capture the complex nature of alignment, we identify five key dimensions to formalize the relationship between any pair of behavior: time, sequence, meaning, form, and modality. We show how assumptions regarding the underlying mechanism of alignment (placed along the continuum of priming vs. grounding) pattern together with operationalizations in terms of the five dimensions. This integrative framework can help researchers in the field of alignment and related phenomena (including behavior matching, mimicry, entrainment, and accommodation) to formulate their hypotheses and operationalizations in a more transparent and systematic manner. The framework also enables us to discover unexplored research avenues and derive new hypotheses regarding alignment.

Abstract

n two ERP experiments, we investigated how the Dutch discourse markers eigenlijk “actually”, signalling expectation disconfirmation, and inderdaad “indeed”, signalling expectation confirmation, affect incremental dialogue comprehension. We investigated their effects on the processing of subsequent (un)predictable words, and on the quality of word representations in memory. Participants read dialogues with (un)predictable endings that followed a discourse marker (eigenlijk in Experiment 1, inderdaad in Experiment 2) or a control adverb. We found no strong evidence that discourse markers modulated online predictability effects elicited by subsequently read words. However, words following eigenlijk elicited an enhanced posterior post-N400 positivity compared with words following an adverb regardless of their predictability, potentially reflecting increased processing costs associated with pragmatically driven discourse updating. No effects of inderdaad were found on online processing, but inderdaad seemed to influence memory for (un)predictable dialogue endings. These findings nuance our understanding of how pragmatic markers affect incremental language comprehension.

Abstract

Children perceive iconic gestures, along with speech they hear. Previous studies have shown
that children integrate information from both modalities. Yet it is not known whether children
can integrate both types of information simultaneously as soon as they are available as adults
do or processes them separately initially and integrate them later. Using electrophysiological
measures, we examined the online neurocognitive processing of gesture-speech integration in
6- to 7-year-old children. We focused on the N400 event-related potentials component which
is modulated by semantic integration load. Children watched video clips of matching or
mismatching gesture-speech combinations, which varied the semantic integration load. The
ERPs showed that the amplitude of the N400 was larger in the mismatching condition than in
the matching condition. This finding provides the first neural evidence that by the ages of 6
or 7, children integrate multimodal semantic information in an online fashion comparable to
that of adults.

Abstract

A fundamental assumption about language is that, regardless of language modality, it faces the linearization problem, i.e., an event that occurs simultaneously in the world has to be split in language to be organized on a temporal scale. However, the visual modality of signed languages allows its users not only to express meaning in a linear manner but also to use iconicity and multiple articulators together to encode information simultaneously. Accordingly, in cases when it is necessary to encode informatively rich events, signers can take advantage of simultaneous encoding in order to represent information about different referents and their actions simultaneously. This in turn would lead to more iconic and direct representation. Up to now, there has been no experimental study focusing on simultaneous encoding of information in signed languages and its possible advantage for efficient communication. In the present study, we assessed how many information units can be encoded simultaneously in Italian Sign Language (LIS) and whether the amount of simultaneously encoded information varies based on the amount of information that is required to be expressed. Twenty-three deaf adults participated in a director-matcher game in which they described 30 images of events that varied in amount of information they contained. Results revealed that as the information that had to be encoded increased, signers also increased use of multiple articulators to encode different information (i.e., kinematic simultaneity) and density of simultaneously encoded information in their production. Present findings show how the fundamental properties of signed languages, i.e., iconicity and simultaneity, are used for the purpose of efficient information encoding in Italian Sign Language (LIS).

Abstract

Linguistic expressions of locative spatial relations in sign languages are mostly visually- motivated representations of space involving mapping of entities and spatial relations between them onto the hands and the signing space. These are also morphologically complex forms. It is debated whether modality-specific aspects of spatial expressions modulate spatial language development differently in signing compared to speaking children. In a picture description task, we compared the use of locative expressions for containment, support and occlusion relations by deaf children acquiring Turkish Sign Language and hearing children acquiring Turkish (3;5-9;11 years). Unlike previous reports suggesting a boosting effect of iconicity, and / or a hindering effect of morphological complexity of the locative forms in sign languages, our results show similar developmental patterns for signing and speaking children's acquisition of these forms. Our results suggest the primacy of cognitive development guiding the acquisition of locative expressions by speaking and signing children.

Abstract

Humans are unique in their ability to communicate information through representational gestures which visually simulate an action (eg. moving hands as if opening a jar). Previous research indicates that the intention to communicate modulates the kinematics (e.g., velocity, size) of such gestures. If and how this modulation influences addressees’ comprehension of gestures have not been investigated. Here we ask whether communicative kinematic modulation enhances semantic comprehension (i.e., identification) of gestures. We additionally investigate whether any comprehension advantage is due to enhanced early identification or late identification. Participants (n = 20) watched videos of representational gestures produced in a more- (n = 60) or less-communicative (n = 60) context and performed a forced-choice recognition task. We tested the isolated role of kinematics by removing visibility of actor’s faces in Experiment I, and by reducing the stimuli to stick-light figures in Experiment II. Three video lengths were used to disentangle early identification from late identification. Accuracy and response time quantified main effects. Kinematic modulation was tested for correlations with task performance. We found higher gesture identification performance in more- compared to less-communicative gestures. However, early identification was only enhanced within a full visual context, while late identification occurred even when viewing isolated kinematics. Additionally, temporally segmented acts with more post-stroke holds were associated with higher accuracy. Our results demonstrate that communicative signaling, interacting with other visual cues, generally supports gesture identification, while kinematic modulation specifically enhances late identification in the absence of other cues. Results provide insights into mutual understanding processes as well as creating artificial communicative agents.

Abstract

Social interaction requires us to recognize subtle cues in behavior, such as kinematic differences in actions and gestures produced with different social intentions. Neuroscientific studies indicate that the putative mirror neuron system (pMNS) in the premotor cortex and mentalizing system (MS) in the medial prefrontal cortex support inferences about contextually unusual actions. However, little is known regarding the brain dynamics of these systems when viewing communicatively exaggerated kinematics. In an event-related functional magnetic resonance imaging experiment, 28 participants viewed stick-light videos of pantomime gestures, recorded in a previous study, which contained varying degrees of communicative exaggeration. Participants made either social or nonsocial classifications of the videos. Using participant responses and pantomime kinematics, we modeled the probability of each video being classified as communicative. Interregion connectivity and activity were modulated by kinematic exaggeration, depending on the task. In the Social Task, communicativeness of the gesture increased activation of several pMNS and MS regions and modulated top-down coupling from the MS to the pMNS, but engagement of the pMNS and MS was not found in the nonsocial task. Our results suggest that expectation violations can be a key cue for inferring communicative intention, extending previous findings from wholly unexpected actions to more subtle social signaling.

Abstract

How can people communicate successfully while keeping resource costs low in the face of ambiguity? We present a principled theoretical analysis comparing two strategies for disambiguation in communication: (i) pragmatic reasoning, where communicators reason about each other, and (ii) other-initiated repair, where communicators signal and resolve trouble interactively. Using agent-based simulations and computational complexity analyses, we compare the efficiency of these strategies in terms of communicative success, computation cost and interaction cost. We show that agents with a simple repair mechanism can increase efficiency, compared to pragmatic agents, by reducing their computational burden at the cost of longer interactions. We also find that efficiency is highly contingent on the mechanism, highlighting the importance of explicit formalisation and computational rigour.

Abstract

Ideophones, also termed “mimetics” or “expressives,” are marked words that depict sensory imagery. They are found in many of the world’s languages, and sizable lexical classes of ideophones are particularly well-documented in languages of Asia, Africa, and the Americas. Ideophones are not limited to onomatopoeia like meow and smack, but cover a wide range of sensory domains, such as manner of motion (e.g., plisti plasta ‘splish-splash’ in Basque), texture (e.g., tsaklii ‘rough’ in Ewe), and psychological states (e.g., wakuwaku ‘excited’ in Japanese). Across languages, ideophones stand out as marked words due to special phonotactics, expressive morphology including certain types of reduplication, and relative syntactic independence, in addition to production features like prosodic foregrounding and common co-occurrence with iconic gestures.

Three intertwined issues have been repeatedly debated in the century-long literature on ideophones. (a) Definition: Isolated descriptive traditions and cross-linguistic variation have sometimes obscured a typologically unified view of ideophones, but recent advances show the promise of a prototype definition of ideophones as conventionalised depictions in speech, with room for language-specific nuances. (b) Integration: The variable integration of ideophones across linguistic levels reveals an interaction between expressiveness and grammatical integration, and has important implications for how to conceive of dependencies between linguistic systems. (c) Iconicity: Ideophones form a natural laboratory for the study of iconic form-meaning associations in natural languages, and converging evidence from corpus and experimental studies suggests important developmental, evolutionary, and communicative advantages of ideophones.

Abstract

Referent accessibility influences expressions in speech and gestures in similar ways. Speakers mostly use richer forms as noun phrases (NPs) in speech and gesture more when referents have low accessibility, whereas they use reduced forms such as pronouns more often and gesture less when referents have high accessibility. We investigated the relationships between speech and gesture during reference tracking in a pro-drop language—Turkish. Overt pronouns were not strongly associated with accessibility but with pragmatic context (i.e., marking similarity, contrast). Nevertheless, speakers gestured more when referents were re-introduced versus maintained and when referents were expressed with NPs versus pronouns. Pragmatic context did not influence gestures. Further, pronouns in low-accessibility contexts were accompanied with gestures—possibly for reference disambiguation—more often than previously found for non-pro-drop languages in such contexts. These findings enhance our understanding of the relationships between speech and gesture at the discourse level.

Abstract

We report associations between vowel sounds, graphemes, and colours collected online from over 1000 Dutch speakers. We provide open materials including a Python implementation of the structure measure, and code for a single page web application to run simple cross-modal tasks. We also provide a full dataset of colour-vowel associations from 1164 participants, including over 200 synaesthetes identified using consistency measures. Our analysis reveals salient patterns in cross-modal associations, and introduces a novel measure of isomorphism in cross-modal mappings. We find that while acoustic features of vowels significantly predict certain mappings (replicating prior work), both vowel phoneme category and grapheme category are even better predictors of colour choice. Phoneme category is the best predictor of colour choice overall, pointing to the importance of phonological representations in addition to acoustic cues. Generally, high/front vowels are lighter, more green, and more yellow than low/back vowels. Synaesthetes respond more strongly on some dimensions, choosing lighter and more yellow colours for high and mid front vowels than non-synaesthetes. We also present a novel measure of cross-modal mappings adapted from ecology, which uses a simulated distribution of mappings to measure the extent to which participants' actual mappings are structured isomorphically across modalities. Synaesthetes have mappings that tend to be more structured than non-synaesthetes, and more consistent colour choices across trials correlate with higher structure scores. Nevertheless, the large majority (~70%) of participants produce structured mappings, indicating that the capacity to make isomorphically structured mappings across distinct modalities is shared to a large extent, even if the exact nature of mappings varies across individuals. Overall, this novel structure measure suggests a distribution of structured cross-modal association in the population, with synaesthetes on one extreme and participants with unstructured associations on the other.

Abstract

Do interlocutors adjust their conversational strategies to the specific contextual demands of a given situation? Prior studies have yielded conflicting results, making it unclear how strategies vary with demands. We combine insights from qualitative and quantitative approaches in a within-participant experimental design involving two different contexts: spontaneously occurring conversations (SOC) and task-oriented conversations (TOC). We systematically assess backchanneling, other-repair and linguistic alignment. We find that SOC exhibit a higher number of backchannels, a reduced and more generic repair format and higher rates of lexical and syntactic alignment. TOC are characterized by a high number of specific repairs and a lower rate of lexical and syntactic alignment. However, when alignment occurs, more linguistic forms are aligned. The findings show that conversational strategies adapt to specific contextual demands.

Abstract

This chapter makes the case for ‘ideophone’ as a comparative concept: a notion that captures a recurrent typological pattern and provides a template for understanding language-specific phenomena that prove similar. It revises an earlier definition to account for the observation that ideophones typically form an open lexical class, and uses insights from canonical typology to explore the larger typological space. According to the resulting definition, a canonical ideophone is a member of an open lexical class of marked words that depict sensory imagery. The five elements of this definition can be seen as dimensions that together generate a possibility space to characterise cross-linguistic diversity in depictive means of expression. This approach allows for the systematic comparative treatment of ideophones and ideophone-like phenomena. Some phenomena in the larger typological space are discussed to demonstrate the utility of the approach: phonaesthemes in European languages, specialised semantic classes in West-Chadic, diachronic diversions in Aslian, and depicting constructions in signed languages.

Abstract

Visual information conveyed by iconic hand gestures and visible speech can enhance speech comprehension under adverse listening conditions for both native and non‐native listeners. However, how a listener allocates visual attention to these articulators during speech comprehension is unknown. We used eye‐tracking to investigate whether and how native and highly proficient non‐native listeners of Dutch allocated overt eye gaze to visible speech and gestures during clear and degraded speech comprehension. Participants watched video clips of an actress uttering a clear or degraded (6‐band noise‐vocoded) action verb while performing a gesture or not, and were asked to indicate the word they heard in a cued‐recall task. Gestural enhancement was the largest (i.e., a relative reduction in reaction time cost) when speech was degraded for all listeners, but it was stronger for native listeners. Both native and non‐native listeners mostly gazed at the face during comprehension, but non‐native listeners gazed more often at gestures than native listeners. However, only native but not non‐native listeners' gaze allocation to gestures predicted gestural benefit during degraded speech comprehension. We conclude that non‐native listeners might gaze at gesture more as it might be more challenging for non‐native listeners to resolve the degraded auditory cues and couple those cues to phonological information that is conveyed by visible speech. This diminished phonological knowledge might hinder the use of semantic information that is conveyed by gestures for non‐native compared to native listeners. Our results demonstrate that the degree of language experience impacts overt visual attention to visual articulators, resulting in different visual benefits for native versus non‐native listeners.

Abstract

Listeners are often challenged by adverse listening conditions during language comprehension induced by external factors, such as noise, but also internal factors, such as being a non-native listener. Visible cues, such as semantic information conveyed by iconic gestures, can enhance language comprehension in such situations. Using magnetoencephalography (MEG) we investigated whether spatiotemporal oscillatory dynamics can predict a listener's benefit of iconic gestures during language comprehension in both internally (non-native versus native listeners) and externally (clear/degraded speech) induced adverse listening conditions. Proficient non-native speakers of Dutch were presented with videos in which an actress uttered a degraded or clear verb, accompanied by a gesture or not, and completed a cued-recall task after every video. The behavioral and oscillatory results obtained from non-native listeners were compared to an MEG study where we presented the same stimuli to native listeners (Drijvers et al., 2018a). Non-native listeners demonstrated a similar gestural enhancement effect as native listeners, but overall scored significantly slower on the cued-recall task. In both native and non-native listeners, an alpha/beta power suppression revealed engagement of the extended language network, motor and visual regions during gestural enhancement of degraded speech comprehension, suggesting similar core processes that support unification and lexical access processes. An individual's alpha/beta power modulation predicted the gestural benefit a listener experienced during degraded speech comprehension. Importantly, however, non-native listeners showed less engagement of the mouth area of the primary somatosensory cortex, left insula (beta), LIFG and ATL (alpha) than native listeners, which suggests that non-native listeners might be hindered in processing the degraded phonological cues and coupling them to the semantic information conveyed by the gesture. Native and non-native listeners thus demonstrated similar yet distinct spatiotemporal oscillatory dynamics when recruiting visual cues to disambiguate degraded speech.

Abstract

Studies have claimed that blind people’s spatial representations are different from sighted people, and blind people display superior auditory processing. Due to the nature of auditory and haptic information, it has been proposed that blind people have spatial representations that are more sequential than sighted people. Even the temporary loss of sight—such as through blindfolding—can affect spatial representations, but not much research has been done on this topic. We compared blindfolded and sighted people’s linguistic spatial expressions and non-linguistic localization accuracy to test how blindfolding affects the representation of path in auditory motion events. We found that blindfolded people were as good as sighted people when localizing simple sounds, but they outperformed sighted people when localizing auditory motion events. Blindfolded people’s path related speech also included more sequential, and less holistic elements. Our results indicate that even temporary loss of sight influences spatial representations of auditory motion events

Abstract

The sign languages of deaf communities and the gestures produced by hearing people are communicative systems that exploit the manual-visual modality as means of expression. Despite their striking differences they share the property of iconicity, understood as the direct relationship between a symbol and its referent. Here we investigate whether non-signing hearing adults exploit their implicit knowledge of gestures to bootstrap accurate understanding of the meaning of iconic signs they have never seen before. In Study 1 we show that for some concepts gestures exhibit systematic forms across participants, and share different degrees of form overlap with the signs for the same concepts (full, partial, and no overlap). In Study 2 we found that signs with stronger resemblance with signs are more accurately guessed and are assigned higher iconicity ratings by non-signers than signs with low overlap. In addition, when more people produced a systematic gesture resembling a sign, they assigned higher iconicity ratings to that sign. Furthermore, participants had a bias to assume that signs represent actions and not objects. The similarities between some signs and gestures could be explained by deaf signers and hearing gesturers sharing a conceptual substrate that is rooted in our embodied experiences with the world. The finding that gestural knowledge can ease the interpretation of the meaning of novel signs and predicts iconicity ratings is in line with embodied accounts of cognition and the influence of prior knowledge to acquire new schemas. Through these mechanisms we propose that iconic gestures that overlap in form with signs may serve as some type of ‘manual cognates’ that help non-signing adults to break into a new language at first exposure.

Abstract

Thematic roles such as Agent and Instrument have a long-standing place in theories of event representation. Nonetheless, the structure of these categories has been difficult to determine. We investigated how instrumental events, such as someone slicing bread with a knife, are categorized in English. Speakers described a variety of typical and atypical instrumental events, and we determined the similarity structure of their descriptions using correspondence analysis. We found that events where the instrument is an extension of an intentional agent were most likely to elicit similar language, highlighting the importance of agency in structuring instrumental categories.

Abstract

The status of thematic roles such as Agent and Patient in cognitive science is highly controversial: To some they are universal components of core knowledge, to others they are scholarly fictions without psychological reality. We address this debate by posing two critical questions: to what extent do humans represent events in terms of abstract role categories, and to what extent are these categories shaped by universal cognitive biases? We review a range of literature that contributes answers to these questions: psycholinguistic and event cognition experiments with adults, children, and infants; typological studies grounded in cross-linguistic data; and studies of emerging sign languages. We pose these questions for a variety of roles and find that the answers depend on the role. For Agents and Patients, there is strong evidence for abstract role categories and a universal bias to distinguish the two roles. For Goals and Recipients, we find clear evidence for abstraction but mixed evidence as to whether there is a bias to encode Goals and Recipients as part of one or two distinct categories. Finally, we discuss the Instrumental role and do not find clear evidence for either abstraction or universal biases to structure instrumental categories.

Abstract

Speakers can adapt their speech and co-speech gestures based on knowledge shared with an addressee (common ground-based recipient design). Here, we investigate whether these adaptations are modulated by the speaker’s age and cognitive abilities. Younger and older participants narrated six short comic stories to a same-aged addressee. Half of each story was known to both participants, the other half only to the speaker. The two age groups did not differ in terms of the number of words and narrative events mentioned per narration, or in terms of gesture frequency, gesture rate, or percentage of events expressed multimodally. However, only the younger participants reduced the amount of verbal and gestural information when narrating mutually known as opposed to novel story content. Age-related differences in cognitive abilities did not predict these differences in common ground-based recipient design. The older participants’ communicative behaviour may therefore also reflect differences in social or pragmatic goals.

Abstract

In everyday life, people see, describe and remember motion events. We tested whether the type of motion event information (path or manner) encoded in speech and gesture predicts which information is remembered and if this varies across speakers of typologically different languages. We focus on intransitive motion events (e.g., a woman running to a tree) that are described differently in speech and co-speech gesture across languages, based on how these languages typologically encode manner and path information (Kita & Özyürek, 2003; Talmy, 1985). Speakers of Dutch (n = 19) and Turkish (n = 22) watched and described motion events. With a surprise (i.e. unexpected) recognition memory task, memory for manner and path components of these events was measured. Neither Dutch nor Turkish speakers’ memory for manner went above chance levels. However, we found a positive relation between path speech and path change detection: participants who described the path during encoding were more accurate at detecting changes to the path of an event during the memory task. In addition, the relation between path speech and path memory changed with native language: for Dutch speakers encoding path in speech was related to improved path memory, but for Turkish speakers no such relation existed. For both languages, co-speech gesture did not predict memory speakers. We discuss the implications of these findings for our understanding of the relations between speech, gesture, type of encoding in language and memory.

Abstract

Action, gesture, and sign represent unique aspects of human communication that use form and movement to convey meaning. Researchers typically use manual coding of video data to characterize naturalistic, meaningful movements at various levels of description, but the availability of markerless motion-tracking technology allows for quantification of the kinematic features of gestures or any meaningful human movement. We present a novel protocol for extracting a set of kinematic features from movements recorded with Microsoft Kinect. Our protocol captures spatial and temporal features, such as height, velocity, submovements/strokes, and holds. This approach is based on studies of communicative actions and gestures and attempts to capture features that are consistently implicated as important kinematic aspects of communication. We provide open-source code for the protocol, a description of how the features are calculated, a validation of these features as quantified by our protocol versus manual coders, and a discussion of how the protocol can be applied. The protocol effectively quantifies kinematic features that are important in the production (e.g., characterizing different contexts) as well as the comprehension (e.g., used by addressees to understand intent and semantics) of manual acts. The protocol can also be integrated with qualitative analysis, allowing fast and objective demarcation of movement units, providing accurate coding even of complex movements. This can be useful to clinicians, as well as to researchers studying multimodal communication or human–robot interactions. By making this protocol available, we hope to provide a tool that can be applied to understanding meaningful movement characteristics in human communication.

Abstract

In synaesthetes specific sensory stimuli (e.g., black letters) elicit additional experiences (e.g. colour). Synaesthesia is highly prevalent among individuals with autism spectrum disorder but the mechanisms of this co-occurrence are not clear. We hypothesized autism and synaesthesia share atypical sensory sensitivity and perception. We assessed autistic traits, sensory sensitivity, and visual perception in two synaesthete populations. In Study 1, synaesthetes (N=79, of different types) scored higher than non-synaesthetes (N=76) on the Attention-to-detail and Social skills subscales of the Autism Spectrum Quotient indexing autistic traits, and on the Glasgow Sensory Questionnaire indexing sensory hypersensitivity and hyposensitivity which frequently occur in autism. Synaesthetes performed two local/global visual tasks because individuals with autism typically show a bias toward detail processing. In synaesthetes, elevated motion coherence thresholds suggested reduced global motion perception and higher accuracy on an embedded figures task suggested enhanced local perception. In Study 2 sequence-space synaesthetes (N=18) completed the same tasks. Questionnaire and embedded figures results qualitatively resembled Study 1 results but no significant group differences with non-synaesthetes (N=20) were obtained. Unexpectedly, sequence-space synaesthetes had reduced motion coherence thresholds. Altogether, our studies suggest atypical sensory sensitivity and a bias towards detail processing are shared features of synaesthesia and autism spectrum disorder.