Publications

Abstract

When we communicate with others, we often repeat aspects of each other's communicative behavior such as sentence structures and words. Such behavioral alignment has been mostly studied for speech or text. Yet, language use is mostly multimodal, flexibly using speech and gestures to convey messages. Here, we explore the use of alignment in speech (words) and co-speech gestures (iconic gestures) in a referential communication task aimed at finding labels for novel objects in interaction. In particular, we investigate how people flexibly use lexical and gestural alignment to create shared labels for novel objects and whether alignment in speech and gesture are related over time. The present study shows that interlocutors establish shared labels multimodally, and alignment in words and iconic gestures are used throughout the interaction. We also show that the amount of lexical alignment positively associates with the amount of gestural alignment over time, suggesting a close relationship between alignment in the vocal and manual modalities.

Abstract

Recognizing the limitations of standard vision assessments in capturing the real-world capabilities of individuals with low vision, we investigated the potential of the Seguin Form Board Test (SFBT), a widely-used intelligence assessment employing a visuo-haptic shape-fitting task, as an estimator of vision's practical utility. We present findings from 23 children from India, who underwent treatment for congenital bilateral dense cataracts, and 21 control participants. To assess the development of functional visual ability, we conducted the SFBT and the standard measure of visual acuity, before and longitudinally after treatment. We observed a dissociation in the development of shape-fitting and visual acuity. Improvements of patients' shape-fitting preceded enhancements in their visual acuity after surgery and emerged even with acuity worse than that of control participants. Our findings highlight the importance of incorporating multi-modal and cognitive aspects into evaluations of visual proficiency in low-vision conditions, to better reflect vision's impact on daily activities.

Abstract

This paper presents a model specification for group comparisons regarding a functional trend over time within a trial and learning across a series of trials in intensive binary longitudinal eye-tracking data. The functional trend and learning effects are modeled using by-variable smooth functions. This model specification is formulated as a generalized additive mixed model, which allowed for the use of the freely available mgcv package (Wood in Package ‘mgcv.’ https://cran.r-project.org/web/packages/mgcv/mgcv.pdf, 2023) in R. The model specification was applied to intensive binary longitudinal eye-tracking data, where the questions of interest concern differences between individuals with and without brain injury in their real-time language comprehension and how this affects their learning over time. The results of the simulation study show that the model parameters are recovered well and the by-variable smooth functions are adequately predicted in the same condition as those found in the application.

Abstract

Background
Language is multimodal and situated in rich visual contexts. Language is also incremental, unfolding moment-to-moment in real time, yet few studies have examined how spoken language interacts with gesture and visual context during multimodal language processing. Gesture is a rich communication cue that is integrally related to speech and often depicts concrete referents from the visual world. Using eye-tracking in an adapted visual world paradigm, we examined how participants with and without moderate-severe traumatic brain injury (TBI) use gesture to resolve temporary referential ambiguity.

Methods
Participants viewed a screen with four objects and one video. The speaker in the video produced sentences (e.g., “The girl will eat the very good sandwich”), paired with either a meaningful gesture (e.g., sandwich-holding gesture) or a meaningless grooming movement (e.g., arm scratch) at the verb “will eat.” We measured participants’ gaze to the target object (e.g., sandwich), a semantic competitor (e.g., apple), and two unrelated distractors (e.g., piano, guitar) during the critical window between movement onset in the gesture modality and onset of the spoken referent in speech.

Results
Both participants with and without TBI were more likely to fixate the target when the speaker produced a gesture compared to a grooming movement; however, relative to non-injured participants, the effect was significantly attenuated in the TBI group.

Discussion
We demonstrated evidence of reduced speech-gesture integration in participants with TBI relative to non-injured peers. This study advances our understanding of the communicative abilities of adults with TBI and could lead to a more mechanistic account of the communication difficulties adults with TBI experience in rich communication contexts that require the processing and integration of multiple co-occurring cues. This work has the potential to increase the ecological validity of language assessment and provide insights into the cognitive and neural mechanisms that support multimodal language processing.

Abstract

Developing efficient electromagnetic interference shielding materials has become significantly important in present times. This paper reports a series of (Ba1-xCax)(Ti0.9Sn0.1)O3 (BCTS) ((x =0, 0.01, 0.05, & 0.1)ceramics synthesized by conventional method which were studied for electromagnetic interference shielding (EMI) applications in X-band (8-12.4 GHz). EMI shielding properties and all S parameters (S11 & S12) of BCTS ceramic pellets were measured in the frequency range (8-12.4 GHz) using a Vector Network Analyser (VNA). The BCTS ceramic pellets for x = 0.05 showed maximum total effective shielding of 46 dB indicating good shielding behaviour for high-frequency applications. However, the development of lead-free ceramics with different concentrations usually requires iterative experiments resulting in, longer development cycles and higher costs. To address this, we used a machine learning (ML) strategy to predict the EMI shielding for different concentrations and experimentally verify the concentration predicted to give the best EMI shielding. The ML model predicted BCTS ceramics with concentration (x = 0.06, 0.07, 0.08, and 0.09) to have higher shielding values. On experimental verification, a shielding value of 58 dB was obtained for x = 0.08, which was significantly higher than what was obtained experimentally before applying the ML approach. Our results show the potential of using ML in accelerating the process of optimal material development, reducing the need for repeated experimental measures significantly.

Abstract

Studies of the impact of brain injury on memory processes often focus on the quantity and episodic richness of those recollections. Here, we argue that the organization of one's recollections offers critical insights into the impact of brain injury on functional memory. It is well-established in studies of word list memory that free recall of unrelated words exhibits a clear temporal organization. This temporal contiguity effect refers to the fact that the order in which word lists are recalled reflects the original presentation order. Little is known, however, about the organization of recall for semantically rich materials, nor how recall organization is impacted by hippocampal damage and memory impairment. The present research is the first study, to our knowledge, of temporal organization in semantically rich narratives in three groups: (1) Adults with bilateral hippocampal damage and severe declarative memory impairment, (2) adults with bilateral ventromedial prefrontal cortex (vmPFC) damage and no memory impairment, and (3) demographically matched non-brain-injured comparison participants. We find that although the narrative recall of adults with bilateral hippocampal damage reflected the temporal order in which those narratives were experienced above chance levels, their temporal contiguity effect was significantly attenuated relative to comparison groups. In contrast, individuals with vmPFC damage did not differ from non-brain-injured comparison participants in temporal contiguity. This pattern of group differences yields insights into the cognitive and neural systems that support the use of temporal organization in recall. These data provide evidence that the retrieval of temporal context in narrative recall is hippocampal-dependent, whereas damage to the vmPFC does not impair the temporal organization of narrative recall. This evidence of limited but demonstrable organization of memory in participants with hippocampal damage and amnesia speaks to the power of narrative structures in supporting meaningfully organized recall despite memory impairment.

Abstract

Purpose:
Traumatic brain injury (TBI) is a leading cause of death and disability among adults in the United States. There is evidence to suggest the peripheral vestibular system is vulnerable to damage in individuals with TBI. However, there are limited prospective studies that describe the type and frequency of vestibular impairment in individuals with chronic moderate–severe TBI (> 6 months postinjury).

Method:
Cervical and ocular vestibular evoked myogenic potentials (VEMPs) and video head impulse test (vHIT) were used to assess the function of otolith organ and horizontal semicircular canal (hSCC) pathways in adults with chronic moderate–severe TBI and in noninjured comparison (NC) participants. Self-report questionnaires were administered to participants with TBI to determine prevalence of vestibular symptoms and quality of life associated with those symptoms.

Results:
Chronic moderate–severe TBI was associated with a greater degree of impairment in otolith organ, rather than hSCC, pathways. About 63% of participants with TBI had abnormal VEMP responses, compared to only ~10% with abnormal vHIT responses. The NC group had significantly less abnormal VEMP responses (~7%), while none of the NC participants had abnormal vHIT responses. As many as 80% of participants with TBI reported vestibular symptoms, and up to 36% reported that these symptoms negatively affected their quality of life.

Conclusions:
Adults with TBI reported vestibular symptoms and decreased quality of life related to those symptoms and had objective evidence of peripheral vestibular impairment. Vestibular testing for adults with chronic TBI who report persistent dizziness and imbalance may serve as a guide for treatment and rehabilitation in these individuals.

Abstract

Conversation requires a substantial amount of coordination between dialogue participants, from managing turn taking to negotiating mutual understanding. Part of this coordination effort surfaces as the reuse of linguistic behaviour across speakers, a process often referred to as alignment. While the presence of linguistic alignment is well documented in the literature, several questions remain open, including the extent to which patterns of reuse across speakers have an impact on the emergence of labelling conventions for novel referents. In this study, we put forward a methodology for automatically detecting shared lemmatised constructions---expressions with a common lexical core used by both speakers within a dialogue---and apply it to a referential communication corpus where participants aim to identify novel objects for which no established labels exist. Our analyses uncover the usage patterns of shared constructions in interaction and reveal that features such as their frequency and the amount of different constructions used for a referent are associated with the degree of object labelling convergence the participants exhibit after social interaction. More generally, the present study shows that automatically detected shared constructions offer a useful level of analysis to investigate the dynamics of reference negotiation in dialogue.

Abstract

Gestures are integral components of face-to-face communication. They unfold over time, often following predictable movement phases of preparation, stroke, and re-
traction. Yet, the prevalent approach to automatic gesture detection treats the problem as binary classification, classifying a segment as either containing a gesture or not, thus failing to capture its inherently sequential and contextual nature. To address this, we introduce a novel framework that reframes the task as a multi-phase sequence labeling problem rather than binary classification. Our model processes sequences of skeletal movements over time windows, uses Transformer encoders to learn contextual embeddings, and leverages Conditional Random Fields to perform sequence labeling. We evaluate our proposal on a large dataset of diverse co-speech gestures in task-oriented face-to-face dialogues. The results consistently demonstrate that our method significantly outperforms strong baseline models in detecting gesture strokes. Furthermore, applying Transformer encoders to learn contextual embeddings from movement sequences substantially improves gesture unit detection. These results highlight our framework’s capacity to capture the fine-grained dynamics of co-speech gesture phases, paving the way for more nuanced and accurate gesture detection and analysis.

Abstract

Purpose:
Assessing fluency in aphasia is diagnostically important for determining aphasia type and severity and therapeutically important for determining appropriate treatment targets. However, wide variability in the measures and criteria used to assess fluency, as revealed by a recent survey of clinicians (Gordon & Clough, 2022), results in poor reliability. Furthermore, poor specificity in many fluency measures makes it difficult to identify the underlying impairments. Here, we introduce the Flu-ID Aphasia, an evidence-based tool that provides a more informative method of assessing fluency by capturing the range of behaviors that can affect the flow of speech in aphasia.

Method:
The development of the Flu-ID was based on prior evidence about factors underlying fluency (Clough & Gordon, 2020; Gordon & Clough, 2020) and clinical perceptions about the measurement of fluency (Gordon & Clough, 2022). Clinical utility is maximized by automated counting of fluency behaviors in an Excel template. Reliability is maximized by outlining thorough guidelines for transcription and coding. Eighteen narrative samples representing a range of fluency were coded independently by the authors to examine the Flu-ID's utility, reliability, and validity.

Results:
Overall reliability was very good, with point-to-point agreement of 86% between coders. Ten of the 12 dimensions showed good to excellent reliability. Validity analyses indicated that Flu-ID scores were similar to clinician ratings on some dimensions, but differed on others. Possible reasons and implications of the discrepancies are discussed, along with opportunities for improvement.

Conclusions:
The Flu-ID assesses fluency in aphasia using a consistent and comprehensive set of measures and semi-automated procedures to generate individual fluency profiles. The profiles generated in the current study illustrate how similar ratings of fluency can arise from different underlying impairments. Supplemental materials include an analysis template, extensive guidelines for transcription and coding, a completed sample, and a quick reference guide.

Abstract

Language is inherently multimodal. In spoken languages, combined spoken and visual signals (e.g., co-speech gestures) are an integral part of linguistic structure and language representation. This requires an extension of the parallel architecture, which needs to include the visual signals concomitant to speech. We present the evidence for the multimodality of language. In addition, we propose that distributional semantics might provide a format for integrating speech and co-speech gestures in a common semantic representation.

Abstract

Linguistic communication is an intrinsically social activity that enables us to share thoughts across minds. Many complex social uses of language can be captured by domain-general representations of other minds (i.e., mentalistic representations) that externally modulate linguistic meaning through Gricean reasoning. However, here we show that representations of others’ attention are embedded within language itself. Across ten languages, we show that demonstratives—basic grammatical words (e.g.,“this”/“that”) which are evolutionarily ancient, learned early in life, and documented in all known languages—are intrinsic attention tools. Beyond their spatial meanings, demonstratives encode both joint attention and the direction in which the listenermmust turn to establish it. Crucially, the frequency of the spatial and attentional uses of demonstratives varies across languages, suggesting that both spatial and mentalistic representations are part of their conventional meaning. Using computational modeling, we show that mentalistic representations of others’ attention are internally encoded in demonstratives, with their effect further boosted by Gricean reasoning. Yet, speakers are largely unaware of this, incorrectly reporting that they primarily capture spatial representations. Our findings show that representations of other people’s cognitive states (namely, their attention) are embedded in language and suggest that the most basic building blocks of the linguistic system crucially rely on social cognition.

Abstract

Indian Sign Language has limited resources for developing machine learning and data-driven approaches for automated language processing. Though text/audio-based language processing techniques have shown colossal research interest and tremendous improvements in the last few years, Sign Languages still need to catch up due to the need for more resources. To bridge this gap, in this work, we propose iSign: a benchmark for Indian Sign Language (ISL) Processing. We make three primary contributions to this work. First, we release one of the largest ISL-English datasets with more than video-sentence/phrase pairs. To the best of our knowledge, it is the largest sign language dataset available for ISL. Second, we propose multiple NLP-specific tasks (including SignVideo2Text, SignPose2Text, Text2Pose, Word Prediction, and Sign Semantics) and benchmark them with the baseline models for easier access to the research community. Third, we provide detailed insights into the proposed benchmarks with a few linguistic insights into the working of ISL. We streamline the evaluation of Sign Language processing, addressing the gaps in the NLP research community for Sign Languages. We release the dataset, tasks and models via the following website: https://exploration-lab.github.io/iSign/

Abstract

Expressing Left-Right relations is challenging for speaking-children. Yet, this challenge was absent for signing-children, possibly due to iconicity in the visual-spatial modality of expression. We investigate whether there is also a modality advantage when speaking-children’s co-speech gestures are considered. Eight-year-old child and adult hearing monolingual Turkish speakers and deaf signers of Turkish-Sign-Language described pictures of objects in various spatial relations. Descriptions were coded for informativeness in speech, sign, and speech-gesture combinations for encoding Left-Right relations. The use of co-speech gestures increased the informativeness of speakers’ spatial expressions compared to speech-only. This pattern was more prominent for children than adults. However, signing-adults and children were more informative than child and adult speakers even when co-speech gestures were considered. Thus, both speaking- and signing-children benefit from iconic expressions in visual modality. Finally, in each modality, children were less informative than adults, pointing to the challenge of this spatial domain in development.

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

*=shared first authorship
Children across the world acquire their first language(s) naturally, regardless of typology or modality (e.g. sign or spoken). Various attempts have been made to explain the puzzle of language acquisition using several approaches, trying to understand to what extent it can be explained by what children bring to language-learning situations as well as what they learn from the input and the interactive context. However, most of these approaches consider only speech development, thus ignoring the inherently multimodal nature of human language. As a multimodal view of language is becoming more widely adopted for the study of adult language, a multimodal approach to language acquisition is inevitable. Not only do children have the capacity to learn spoken and sign language equally easily, but spoken language acquisition consists of learning to coordinate linguistic expressions in both modalities, that is, in both speech and gesture. To provide a step forward in this direction, this article aims to synthesize findings from research studies that take a multimodal perspective on language acquisition in different sign and spoken languages, including the development of speech and accompanying gestures. Our review shows that while some aspects of language acquisition seem to be modality-independent, others might differ according to the affordances of each modality when used separately as well as together (either in sign, speech, and/or gesture). We argue that these findings need to be integrated into our understanding of language acquisition. We also identify which areas need future research for both spoken and sign language acquisition, taking into account not only multimodal but also cross-linguistic variation.

Abstract

Speakers tend to engage in adaptive behavior, known as entrainment, when they reuse their partner's linguistic representations, including lexical, acoustic prosodic, semantic, or syntactic structures during a conversation. Studies have explored the relationship between entrainment and social factors such as likeability, task success, and rapport. Still, limited research has investigated the relationship between entrainment and gaze. To address this gap, we conducted a within-subjects user study (N = 33) to test if gaze behavior of a robotic head affects entrainment of subjects toward the robot on four linguistic dimensions: lexical, syntactic, semantic, and acoustic-prosodic. Our results show that participants entrain more on lexical and acoustic-prosodic features when the robot exhibits well-timed gaze aversions similar to the ones observed in human gaze behavior, as compared to when the robot keeps staring at participants constantly. Our results support the predictions of the computers as social actors (CASA) model and suggest that implementing well-timed gaze aversion behavior in a robot can lead to speech entrainment in human-robot interactions.

Abstract

Somatic practices frequently use imagery, typically via verbal instructions, to scaffold sensorimotor organization and experience, a phenomenon we term “introjection”. We argue that introjection is an imagery practice in which sensorimotor and conceptual aspects are co-orchestrated, suggesting the necessity of crosstalk between somatics, phenomenology, psychology, embodied-enactive cognition, and linguistic research on embodied simulation. We presently focus on the scarcely addressed details of the process necessary to enact instructions of a literal or metaphoric nature through the body. Based on vignettes from dance, Feldenkrais, and Taichi practice, we describe introjection as a complex form of processual sense-making, in which context-interpretive, mental, attentional and physical sub-processes recursively braid. Our analysis focuses on how mental and body-related processes progressively align, inform and augment each other. This dialectic requires emphasis on the active body, which implies that uni-directional models (concept ⇒ body) are inadequate and should be replaced by interactionist alternatives (concept ⇔ body). Furthermore, we emphasize that both the source image itself and the body are specifically conceptualized for the context through constructive operations, and both evolve through their interplay. At this level introjection employs representational operations that are embedded in enactive dynamics of a fully situated person.

Abstract

This study aims to advance our understanding of the nature and source(s) of individual differences in pragmatic language behavior over the adult lifespan. Across four story continuation experiments, we probed adults’ (N = 496 participants, ages 18–82) choice of referential forms (i.e., names vs. pronouns to refer to the main character). Our manipulations were based on Fossard et al.’s (2018) scale of referential complexity which varies according to the visual properties of the scene: low complexity (one character), intermediate complexity (two characters of different genders), and high complexity (two characters of the same gender). Since pronouns signal topic continuity (i.e., that the discourse will continue to be about the same referent), the use of pronouns is expected to decrease as referential complexity increases. The choice of names versus pronouns, therefore, provides insight into participants’ perception of the topicality of a referent, and whether that varies by age and cognitive capacity. In Experiment 1, we used the scale to test the association between referential choice, aging, and cognition, identifying a link between older adults’ switching skills and optimal referential choice. In Experiments 2–4, we tested novel manipulations that could impact the scale and found both the timing of a competitor referent’s presence and emphasis placed on competitors modulated referential choice, leading us to refine the scale for future use. Collectively, Experiments 1–4 highlight what type of contextual information is prioritized at different ages, revealing older adults’ preserved sensitivity to (visual) scene complexity but reduced sensitivity to linguistic prominence cues, compared to younger adults.

Abstract

This study investigated how adults over the lifespan flexibly adapt their use of prosocial speech acts when conveying bad news to communicative partners. Experiment 1a (N = 100 Scottish adults aged 18–72 years) assessed whether participants’ use of prosocial speech acts varied according to audience design considerations (i.e., whether or not the recipient of the news was directly affected). Experiment 1b (N = 100 Scottish adults aged 19–70 years) assessed whether participants adjusted for whether the bad news was more or less severe (an index of general knowledge). Younger adults displayed more flexible adaptation to the recipient manipulation, while no age differences were found for severity. These findings are consistent with prior work showing age-related decline in audience design but not in the use of general knowledge during language production. Experiment 2 further probed younger adults (N = 40, Scottish, aged 18–37 years) and older adults’ (N = 40, Scottish, aged 70–89 years) prosocial linguistic behavior by investigating whether health (vs. nonhealth-related) matters would affect responses. While older adults used prosocial speech acts to a greater extent than younger adults, they did not distinguish between conditions. Our results suggest that prosocial linguistic behavior is likely influenced by a combination of differences in audience design and communicative styles at different ages. Collectively, these findings highlight the importance of situating prosocial speech acts within the pragmatics and aging literature, allowing us to uncover the factors modulating prosocial linguistic behavior at different developmental stages.

Abstract

Speakers and listeners show an informativity bias in the use and interpretation of color modifiers. For example, speakers use color more often when referring to objects that vary in color than to objects with a prototypical color. Likewise, listeners look away from objects with prototypical colors upon hearing that color mentioned. Here we test whether speakers and listeners account for another factor related to informativity: the strength of the association between lexical categories and color. Our results demonstrate that speakers and listeners' choices are indeed influenced by this factor; as such, it should be integrated into current pragmatic theories of informativity and computational models of color reference.

Abstract

With the recent advancements in the field of robotics and the increased focus on having general-purpose robots widely available to the general public, it has become increasingly necessary to pursue research into Human-robot interaction (HRI). While there have been a lot of works discussing frameworks for teaching HRI in educational institutions with a few institutions already offering courses to students, a consensus on the course content still eludes the field. In this work, we highlight a few challenges and opportunities while designing an HRI course from an Indian perspective. These topics warrant further deliberations as they have a direct impact on the design of HRI courses and wider implications for the entire field.

Abstract

People derive contrastive inferences when interpreting adjectives (e.g., inferring that ‘the short pencil’ is being contrasted with a longer one). However, classic eye-tracking studies revealed contrastive inferences with scalar and material adjectives, but not with color adjectives. This was explained as a difference in listeners’ informativity expectations, since color adjectives are often used descriptively (hence not warranting a contrastive interpretation). Here we hypothesized that, beyond these pragmatic factors, perceptual factors (i.e., the relative perceptibility of color, material and scalar contrast) and semantic factors (i.e., the difference between gradable and non-gradable properties) also affect the real-time derivation of contrastive inferences. We tested these predictions in three languages with prenominal modification (English, Hindi, and Hungarian) and found that people derive contrastive inferences for color and scalar adjectives, but not for material adjectives. In addition, the processing of scalar adjectives was more context dependent than that of color and material adjectives, confirming that pragmatic, perceptual and semantic factors affect the derivation of contrastive inferences.

Abstract

Although it is well established that self-related information can rapidly capture our attention and bias cognitive functioning, whether this self-bias can affect language processing remains largely unknown. In addition, there is an ongoing debate as to the functional independence of language processes, notably regarding the syntactic domain. Hence, this study investigated the influence of self-related content on syntactic speech processing. Participants listened to sentences that could contain morphosyntactic anomalies while the masked face identity (self, friend, or unknown faces) was presented for 16 msec preceding the critical word. The language-related ERP components (left anterior negativity [LAN] and P600) appeared for all identity conditions. However, the largest LAN effect followed by a reduced P600 effect was observed for self-faces, whereas a larger LAN with no reduction of the P600 was found for friend faces compared with unknown faces. These data suggest that both early and late syntactic processes can be modulated by self-related content. In addition, alpha power was more suppressed over the left inferior frontal gyrus only when self-faces appeared before the critical word. This may reflect higher semantic demands concomitant to early syntactic operations (around 150–550 msec). Our data also provide further evidence of self-specific response, as reflected by the N250 component. Collectively, our results suggest that identity-related information is rapidly decoded from facial stimuli and may impact core linguistic processes, supporting an interactive view of syntactic processing. This study provides evidence that the self-reference effect can be extended to syntactic processing.

Abstract

We investigated the relationship between visual experience and pragmatic development by testing the socio-communicative skills of a unique population: the Prakash children of India, who received treatment for congenital cataracts after years of visual deprivation. Using two different referential communication tasks, our study investigated Prakash' children ability to produce sufficiently informative referential expressions (e.g., ‘the green pear' or ‘the small plate') and pay attention to their interlocutor's face during the task (Experiment 1), as well as their ability to recognize a speaker's referential intent through non-verbal cues such as head turning and pointing (Experiment 2). Our results show that Prakash children have strong pragmatic skills, but do not look at their interlocutor's face as often as neurotypical children do. However, longitudinal analyses revealed an increase in face fixations, suggesting that over time, Prakash children come to utilize their improved visual skills for efficient referential communication.

Abstract

The present study investigated to what extent children, compared to adults, benefit from gestures to disambiguate degraded speech by manipulating speech signals and manual modality. Dutch-speaking adults (N = 20) and 6- and 7-year-old children (N = 15) were presented with a series of video clips in which an actor produced a Dutch action verb with or without an accompanying iconic gesture. Participants were then asked to repeat what they had heard. The speech signal was either clear or altered into 4- or 8-band noise-vocoded speech. Children had more difficulty than adults in disambiguating degraded speech in the speech-only condition. However, when presented with both speech and gestures, children reached a comparable level of accuracy to that of adults in the degraded-speech-only condition. Furthermore, for adults, the enhancement of gestures was greater in the 4-band condition than in the 8-band condition, whereas children showed the opposite pattern. Gestures help children to disambiguate degraded speech, but children need more phonological information than adults to benefit from use of gestures. Children’s multimodal language integration needs to further develop to adapt flexibly to challenging situations such as degraded speech, as tested in our study, or instances where speech is heard with environmental noise or through a face mask.

Abstract

During face-to-face conversation, transitions between speaker turns are incredibly fast. These fast turn exchanges seem to involve next speakers predicting upcoming semantic information, such that next turn planning can begin before a current turn is complete. Given that face-to-face conversation also involves the use of communicative bodily signals, an important question is how bodily signals such as co-speech hand gestures play into these processes of prediction and fast responding. In this corpus study, we found that hand gestures that depict or refer to semantic information started before the corresponding information in speech, which held both for the onset of the gesture as a whole, as well as the onset of the stroke (the most meaningful part of the gesture). This early timing potentially allows listeners to use the gestural information to predict the corresponding semantic information to be conveyed in speech. Moreover, we provided further evidence that questions with gestures got faster responses than questions without gestures. However, we found no evidence for the idea that how much a gesture precedes its lexical affiliate (i.e., its predictive potential) relates to how fast responses were given. The findings presented here highlight the importance of the temporal relation between speech and gesture and help to illuminate the potential mechanisms underpinning multimodal language processing during face-to-face conversation.

Abstract

Most language use occurs in face-to-face conversation, which involves rapid turn-taking. Seeing communicative bodily signals in addition to hearing speech may facilitate such fast responding. We tested whether this holds for co-speech hand gestures by investigating whether these gestures speed up button press responses to questions. Sixty native speakers of Dutch viewed videos in which an actress asked yes/no-questions, either with or without a corresponding iconic hand gesture. Participants answered the questions as quickly and accurately as possible via button press. Gestures did not impact response accuracy, but crucially, gestures sped up responses, suggesting that response planning may be finished earlier when gestures are seen. How much gestures sped up responses was not related to their timing in the question or their timing with respect to the corresponding information in speech. Overall, these results are in line with the idea that multimodality may facilitate fast responding during face-to-face conversation.

Abstract

The typical pattern of alternating turns in conversation seems trivial at first sight. But a closer look quickly reveals the cognitive challenges involved, with much of it resulting from the fast-paced nature of conversation. One core ingredient to turn coordination is the anticipation of upcoming turn ends so as to be able to ready oneself for providing the next contribution. Across two experiments, we investigated two variables inherent to face-to-face conversation, the presence of visual bodily signals and preceding discourse context, in terms of their contribution to turn end anticipation. In a reaction time paradigm, participants anticipated conversational turn ends better when seeing the speaker and their visual bodily signals than when they did not, especially so for longer turns. Likewise, participants were better able to anticipate turn ends when they had access to the preceding discourse context than when they did not, and especially so for longer turns. Critically, the two variables did not interact, showing that visual bodily signals retain their influence even in the context of preceding discourse. In a pre-registered follow-up experiment, we manipulated the visibility of the speaker's head, eyes and upper body (i.e. torso + arms). Participants were better able to anticipate turn ends when the speaker's upper body was visible, suggesting a role for manual gestures in turn end anticipation. Together, these findings show that seeing the speaker during conversation may critically facilitate turn coordination in interaction.

Abstract

Human language is extremely versatile, combining a limited set of signals in an unlimited number of ways. However, it is unknown whether conversational visual signals feed into the composite utterances with which speakers communicate their intentions. We assessed whether different combinations of visual signals lead to different intent interpretations of the same spoken utterance. Participants viewed a virtual avatar uttering spoken questions while producing single visual signals (i.e., head turn, head tilt, eyebrow raise) or combinations of these signals. After each video, participants classified the communicative intention behind the question. We found that composite utterances combining several visual signals conveyed different meaning compared to utterances accompanied by the single visual signals. However, responses to combinations of signals were more similar to the responses to related, rather than unrelated, individual signals, indicating a consistent influence of the individual visual signals on the whole. This study therefore provides first evidence for compositional, non-additive (i.e., Gestalt-like) perception of multimodal language.

Abstract

The natural ecology of language is conversation, with individuals taking turns speaking to communicate in a back-and-forth fashion. Language in this context involves strings of words that a listener must process while simultaneously planning their own next utterance. It would thus be highly advantageous if language users distributed information within an utterance in a way that may facilitate this processing–planning dynamic. While some studies have investigated how information is distributed at the level of single words or clauses, or in written language, little is known about how information is distributed within spoken utterances produced during naturalistic conversation. It also is not known how information distribution patterns of spoken utterances may differ across languages. We used a set of matched corpora (CallHome) containing 898 telephone conversations conducted in six different languages (Arabic, English, German, Japanese, Mandarin, and Spanish), analyzing more than 58,000 utterances, to assess whether there is evidence of distinct patterns of information distributions at the utterance level, and whether these patterns are similar or differed across the languages. We found that English, Spanish, and Mandarin typically show a back-loaded distribution, with higher information (i.e., surprisal) in the last half of utterances compared with the first half, while Arabic, German, and Japanese showed front-loaded distributions, with higher information in the first half compared with the last half. Additional analyses suggest that these patterns may be related to word order and rate of noun and verb usage. We additionally found that back-loaded languages have longer turn transition times (i.e.,time between speaker turns)

Abstract

How people communicate about motion events and how this is shaped by language typology are mostly studied with a focus on linguistic encoding in speech. Yet, human communication typically involves an interactional exchange of multimodal signals, such as hand gestures that have different affordances for representing event components. Here, we review recent empirical evidence on multimodal encoding of motion in speech and gesture to gain a deeper understanding of whether and how language typology shapes linguistic expressions in different modalities, and how this changes across different sensory modalities of input and interacts with other aspects of cognition. Empirical evidence strongly suggests that Talmy’s typology of event integration predicts multimodal event descriptions in speech and gesture and visual attention to event components prior to producing these descriptions. Furthermore, variability within the event itself, such as type and modality of stimuli, may override the influence of language typology, especially for expression of manner.

Abstract

Humans are the only species that uses communication to teach new knowledge to novices, usually to children (Tomasello, 1999 and Csibra and Gergely, 2006). This context of communication can employ “demonstrations” and it takes place with or without the help of objects (Clark, 1996). Previous research has focused on understanding the nature of demonstrations for very young children and with objects involved. However, little is known about the strategies used in demonstrating an action to an older child in comparison to another adult and without the use of objects, i.e., with gestures only. We tested if during demonstration of an action speakers use different degrees of iconicity in gestures for a child compared to an adult. 18 Italian subjects described to a camera how to make coffee imagining the listener as a 12-year-old child, a novice or an expert adult. While speech was found more informative both for the novice adult and for the child compared to the expert adult, the rate of iconic gestures increased and they were more informative and bigger only for the child compared to both of the adult conditions. Iconicity in gestures can be a powerful communicative strategy in teaching new knowledge to children in demonstrations and this is in line with claims that it can be used as a scaffolding device in grounding knowledge in experience (Perniss et al., 2010).

Abstract

The tracking of entities in discourse is known to be a bimodal phenomenon. Speakers achieve cohesion in speech by alternating between full lexical forms, pronouns, and zero anaphora as they track referents. They also track referents in co-speech gestures. In this study, we explored how viewpoint is deployed in reference tracking, focusing on representations of animate entities in German narrative discourse. We found that gestural viewpoint systematically varies depending on discourse context. Speakers predominantly use character viewpoint in maintained contexts and observer viewpoint in reintroduced contexts. Thus, gestural viewpoint seems to function as a cohesive device in narrative discourse. The findings expand on and provide further evidence for the coordination between speech and gesture on the discourse level that is crucial to understanding the tight link between the two modalities.

Abstract

Does spatial language influence how people think about space? To address this question, we observed children who did not know a conventional language, and tested their performance on nonlinguistic spatial tasks. We studied deaf children living in Istanbul whose hearing losses prevented them from acquiring speech and whose hearing parents had not exposed them to sign. Lacking a conventional language, the children used gestures, called homesigns, to communicate. In Study 1, we asked whether homesigners used gesture to convey spatial relations, and found that they did not. In Study 2, we tested a new group of homesigners on a Spatial Mapping Task, and found that they performed significantly worse than hearing Turkish children who were matched to the deaf children on another cognitive task. The absence of spatial language thus went hand-in-hand with poor performance on the nonlinguistic spatial task, pointing to the importance of spatial language in thinking about space.

Abstract

In human face-to-face communication, language comprehension is a multi-modal, situated activity. However, little is known about how we combine information from these different modalities, and how perceived communicative intentions, often signaled through visual signals, such as eye
gaze, may influence this processing. We address this question by simulating a triadic communication context in which a
speaker alternated her gaze between two different recipients. Participants thus viewed speech-only or speech+gesture
object-related utterances when being addressed (direct gaze) or unaddressed (averted gaze). Two object images followed
each message and participants’ task was to choose the object that matched the message. Unaddressed recipients responded significantly slower than addressees for speech-only
utterances. However, perceiving the same speech accompanied by gestures sped them up to a level identical to
that of addressees. That is, when speech processing suffers due to not being addressed, gesture processing remains intact and enhances the comprehension of a speaker’s message

Abstract

Natural sign languages and gestures are complex communicative systems that allow the incorporation of features of a referent into their structure. They differ, however, in that signs are more conventionalised because they consist of meaningless phonological parameters. There is some evidence that despite non-signers finding iconic signs more memorable they can have more difficulty at articulating their exact phonological components. In the present study, hearing non-signers took part in a sign repetition task in which they had to imitate as accurately as possible a set of iconic and arbitrary signs. Their renditions showed that iconic signs were articulated significantly less accurately than arbitrary signs. Participants were recalled six months later to take part in a sign generation task. In this task, participants were shown the English translation of the iconic signs they imitated six months prior. For each word, participants were asked to generate a sign (i.e., an iconic gesture). The handshapes produced in the sign repetition and sign generation tasks were compared to detect instances in which both renditions presented the same configuration. There was a significant correlation between articulation accuracy in the sign repetition task and handshape overlap. These results suggest some form of gestural interference in the production of iconic signs by hearing non-signers. We also suggest that in some instances non-signers may deploy their own conventionalised gesture when producing some iconic signs. These findings are interpreted as evidence that non-signers process iconic signs as gestures and that in production, only when sign and gesture have overlapping features will they be capable of producing the phonological components of signs accurately.

Abstract

In everyday communication, people not only use speech but
also hand gestures to convey information. One intriguing
question in gesture research has been why gestures take the
specific form they do. Previous research has identified the
speaker-gesturer’s communicative intent as one factor
shaping the form of iconic gestures. Here we investigate
whether communicative intent also shapes the form of
pointing gestures. In an experimental setting, twenty-four
participants produced pointing gestures identifying a referent
for an addressee. The communicative intent of the speakergesturer
was manipulated by varying the informativeness of
the pointing gesture. A second independent variable was the
presence or absence of concurrent speech. As a function of their communicative intent and irrespective of the presence of speech, participants varied the durations of the stroke and the post-stroke hold-phase of their gesture. These findings add to our understanding of how the communicative context influences the form that a gesture takes.

Abstract

In sign languages, where space is often used to talk about space, expressions of spatial relations (e.g., ON, IN, UNDER, BEHIND) may rely on analogue mappings of real space onto signing space. In contrast, spoken languages express space in mostly categorical ways (e.g. adpositions). This raises interesting questions about the role of language modality in the acquisition of expressions of spatial relations. However, whether and to what extent modality influences the acquisition of spatial language is controversial – mostly due to the lack of direct comparisons of Deaf children to Deaf adults and to age-matched hearing children in similar tasks. Furthermore, the previous studies have taken English as the only model for spoken language development of spatial relations.
Therefore, we present a balanced study in which spatial expressions by deaf and hearing children in two different age-matched groups (preschool children and school-age children) are systematically compared, as well as compared to the spatial expressions of adults. All participants performed the same tasks, describing angular (LEFT, RIGHT, FRONT, BEHIND) and non-angular spatial configurations (IN, ON, UNDER) of different objects (e.g. apple in box; car behind box).
The analysis of the descriptions with non-angular spatial relations does not show an effect of modality on the development of
locative expressions in TİD and Turkish. However, preliminary results of the analysis of expressions of angular spatial relations suggest that signers provide angular information in their spatial descriptions
more frequently than Turkish speakers in all three age groups, and thus showing a potentially different developmental pattern in this domain. Implications of the findings with regard to the development of relations in spatial language and cognition will be discussed.

Abstract

This paper reports on an exploration of the ways in which multiple entities are expressed in Turkish Sign Language (TİD). The (descriptive and quantitative) analyses provided are based on a corpus of both spontaneous data and specifically elicited data, in order to provide as comprehensive an account as possible. We have found several devices in TİD for expression of multiple entities, in particular localization, spatial plural predicate inflection, and a specific form used to express multiple entities that are side by side in the same configuration (not reported for any other sign language to date), as well as numerals and quantifiers. In contrast to some other signed languages, TİD does not appear to have a productive system of plural reduplication. We argue that none of the devices encountered in the TİD data is a genuine plural marking device and that the plural interpretation of multiple entity localizations and plural predicate inflections is a by-product of the use of space to indicate the existence or the involvement in an event of multiple entities.