Publications

Abstract

Spoken words are highly variable and therefore listeners interpret speech sounds relative to the surrounding acoustic context, such as the speech rate of a preceding sentence. For instance, a vowel midway between short /ɑ/ and long /a:/ in Dutch is perceived as short /ɑ/ in the context of preceding slow speech, but as long /a:/ if preceded by a fast context. Despite the well-established influence of visual articulatory cues on speech comprehension, it remains unclear whether visual cues to speech rate also influence subsequent spoken word recognition. In two ‘Go Fish’-like experiments, participants were presented with audio-only (auditory speech + fixation cross), visual-only (mute videos of talking head), and audiovisual (speech + videos) context sentences, followed by ambiguous target words containing vowels midway between short /ɑ/ and long /a:/. In Experiment 1, target words were always presented auditorily, without visual articulatory cues. Although the audio-only and audiovisual contexts induced a rate effect (i.e., more long /a:/ responses after fast contexts), the visual-only condition did not. When, in Experiment 2, target words were presented audiovisually, rate effects were observed in all three conditions, including visual-only. This suggests that visual cues to speech rate in a context sentence influence the perception of following visual target cues (e.g., duration of lip aperture), which at an audiovisual integration stage bias participants’ target categorization responses. These findings contribute to a better understanding of how what we see influences what we hear.

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

In human face-to-face communication, speech is frequently accompanied by visual signals, especially communicative hand gestures. Analyzing these visual signals requires detailed manual annotation of video data, which is often a labor-intensive and time-consuming process. To facilitate this process, we here present SPUDNIG (SPeeding Up the Detection of Non-iconic and Iconic Gestures), a tool to automatize the detection and annotation of hand movements in video data. We provide a detailed description of how SPUDNIG detects hand movement initiation and termination, as well as open-source code and a short tutorial on an easy-to-use graphical user interface (GUI) of our tool. We then provide a proof-of-principle and validation of our method by comparing SPUDNIG’s output to manual annotations of gestures by a human coder. While the tool does not entirely eliminate the need of a human coder (e.g., for false positives detection), our results demonstrate that SPUDNIG can detect both iconic and non-iconic gestures with very high accuracy, and could successfully detect all iconic gestures in our validation dataset. Importantly, SPUDNIG’s output can directly be imported into commonly used annotation tools such as ELAN and ANVIL. We therefore believe that SPUDNIG will be highly relevant for researchers studying multimodal communication due to its annotations significantly accelerating the analysis of large video corpora.

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

In face-to-face conversation, recipients might use the bodily movements of the speaker (e.g. gestures) to facilitate language processing. It has been suggested that one way through which this facilitation may happen is prediction. However, for this to be possible, gestures would need to precede speech, and it is unclear whether this is true during natural conversation.
In a corpus of Dutch conversations, we annotated hand gestures that represent semantic information and occurred during questions, and the word(s) which corresponded most closely to the gesturally depicted meaning. Thus, we tested whether representational gestures temporally precede their lexical affiliates. Further, to see whether preceding gestures may indeed facilitate language processing, we asked whether the gesture-speech asynchrony predicts the response time to the question the gesture is part of.
Gestures and their strokes (most meaningful movement component) indeed preceded the corresponding lexical information, thus demonstrating their predictive potential. However, while questions with gestures got faster responses than questions without, there was no evidence that questions with larger gesture-speech asynchronies get faster responses. These results suggest that gestures indeed have the potential to facilitate predictive language processing, but further analyses on larger datasets are needed to test for links between asynchrony and processing advantages.

Abstract

Much evidence has suggested that people conceive of time as flowing directionally in transverse space (e.g., from left to right for English speakers). However, this phenomenon has never been tested in a fully nonlinguistic paradigm where neither stimuli nor task use linguistic labels, which raises the possibility that time is directional only when reading/writing direction has been evoked. In the present study, English-speaking participants viewed a video where an actor sang a note while gesturing and reproduced the duration of the sung note by pressing a button. Results showed that the perceived duration of the note was increased by a long-distance gesture, relative to a short-distance gesture. This effect was equally strong for gestures moving from left to right and from right to left and was not dependent on gestures depicting movement through space; a weaker version of the effect emerged with static gestures depicting spatial distance. Since both our gesture stimuli and temporal reproduction task were nonlinguistic, we conclude that the spatial representation of time is nondirectional: Movement contributes, but is not necessary, to the representation of temporal information in a transverse timeline.

Abstract

The nature of the connection between musical and spatial processing is controversial. While pitch may be described in spatial terms such as “high” or “low”, it is unclear whether pitch and space are associated but separate dimensions or whether they share representational and processing resources. In the present study, we asked participants to judge whether a target vocal note was the same as (or different from) a preceding cue note. Importantly, target trials were presented as video clips where a singer sometimes gestured upward or downward while singing that target note, thus providing an alternative, concurrent source of spatial information. Our results show that pitch discrimination was significantly biased by the spatial movement in gesture, such that downward gestures made notes seem lower in pitch than they really were, and upward gestures made notes seem higher in pitch. These effects were eliminated by spatial memory load but preserved under verbal memory load conditions. Together, our findings suggest that pitch and space have a shared representation such that the mental representation of pitch is audiospatial in nature.

Abstract

The present study investigated the developmental interrelationships between play, gesture use and spoken language development in children aged 18–31 months. The children completed two tasks: (i) a structured measure of pretend (or ‘symbolic’) play and (ii) a measure of vocabulary knowledge in which children have been shown to gesture. Additionally, their productive spoken language knowledge was measured via parental report. The results indicated that symbolic play is positively associated with children’s gesture use, which in turn is positively associated with spoken language knowledge over and above the influence of age. The tripartite relationship between gesture, play and language development is discussed with reference to current developmental theory.

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

The Lexical Retrieval Hypothesis proposes that gestures function at the level of speech production, aiding in the retrieval of lexical items from the mental lexicon. However, empirical evidence for this account is mixed, and some critics argue that a more likely function of gestures during lexical retrieval is a communicative one. The present study was designed to test these predictions against each other by keeping lexical retrieval difficulty constant while varying social context. Participants' gestures were analysed during tip of the tongue experiences when communicating with a partner face-to-face (FTF), while being separated by a screen, or on their own by speaking into a voice recorder. The results show that participants in the FTF context produced significantly more representational gestures than participants in the solitary condition. This suggests that, even in the specific context of lexical retrieval difficulties, representational gestures appear to play predominantly a communicative role.

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

Methods
The present study provides a systematic analysis of co-speech gestures which spontaneously accompany the description of actions in a group of PD patients (N = 23, Hoehn and Yahr Stage III or less) and age-matched healthy controls (N = 22). The analysis considers different co-speech gesture types, using established classification schemes from the field of gesture research. The analysis focuses on the rate of these gestures as well as on their qualitative nature. In doing so, the analysis attempts to overcome several methodological shortcomings of research in this area.
Results
Contrary to expectation, gesture rate was not significantly affected in our patient group, with relatively mild PD. This indicates that co-speech gestures could compensate for speech problems. However, while gesture rate seems unaffected, the qualitative precision of gestures representing actions was significantly reduced.
Conclusions
This study demonstrates the feasibility of carrying out fine-grained, detailed analyses of gestures in PD and offers insights into an as yet neglected facet of communication in patients with PD. Based on the present findings, an important next step is the closer investigation of the qualitative changes in gesture (including different communicative situations) and an analysis of the heterogeneity in co-speech gesture production in PD.

Abstract

Mimicry has been observed regarding a range of nonverbal behaviors, but only recently have researchers started to investigate mimicry in co-speech gestures. These gestures are considered to be crucially different from other aspects of nonverbal behavior due to their tight link with speech. This study provides evidence of mimicry in co-speech gestures in face-to-face dialogue, the most common forum of everyday talk. In addition, it offers an analysis of the functions that mimicked co-speech gestures fulfill in the collaborative process of creating a mutually shared understanding of referring expressions. The implications bear on theories of gesture production, research on grounding, and the mechanisms underlying behavioral mimicry.

Abstract

This study uses a classical referential communication task to
investigate the role of co-speech gestures in the process of
coordination. The study manipulates both the common ground between the interlocutors, as well as the visibility of the gestures they use. The findings show that co-speech gestures are an integral part of the referential utterances speakers
produced with regard to both initial references as well as repeated references, and that the availability of gestures appears to impact on interlocutors’ referential oordination. The results are discussed with regard to past research on
common ground as well as theories of gesture production.

Abstract

There is evidence that co-speech gestures communicate information to addressees and that they are often communicatively intended. However, we still know comparatively little about the role of gestures in the actual process of communication. The present study offers a systematic investigation of speakers’ gesture use before and after addressee feedback. The findings show that when speakers responded to addressees’ feedback gesture rate remained constant when this feedback encouraged clarification, elaboration or correction. However, speakers gestured proportionally less often after feedback when providing confirmatory responses. That is, speakers may not be drawing on gesture in response to addressee feedback per se, but particularly with responses that enhance addressees’ understanding. Further, the large majority of speakers’ gestures changed in their form. They tended to be more precise, larger, or more visually prominent after feedback. Some changes in gesture viewpoint were also observed. In addition, we found that speakers used deixis in speech and gaze to increase the salience of gestures occurring in response to feedback. Speakers appear to conceive of gesture as a useful modality in redesigning utterances to make them more accessible to addressees. The findings further our understanding of recipient design and co-speech gestures in face-to-face dialogue.
Highlights

► Gesture rate remains constant in response to addressee feedback when the response aims to correct or clarify understanding. ► But gesture rate decreases when speakers provide confirmatory responses to feedback signalling correct understanding. ► Gestures are more communicative in response to addressee feedback, particularly in terms of precision, size and visual prominence. ► Speakers make gestures in response to addressee feedback more salient by using deictic markers in speech and gaze.

Abstract

Theorists of language have argued that co-­speech hand gestures are an
intentional part of social communication. The present study provides evidence for these
claims by showing that speakers adjust their gesture use according to their perceived relevance to the audience. Participants were asked to read about items that were and were not useful in a wilderness survival scenario, under the pretense that they would then
explain (on camera) what they learned to one of two different audiences. For one audience (a group of college students in a dormitory orientation activity), the stakes of successful
communication were low;; for the other audience (a group of students preparing for a
rugged camping trip in the mountains), the stakes were high. In their explanations to the camera, participants in the high stakes condition produced three times as many
representational gestures, and spent three times as much time gesturing, than participants in the low stakes condition. This study extends previous research by showing that the anticipated consequences of one’s communication—namely, the degree to which information may be useful to an intended recipient—influences speakers’ use of gesture.

Abstract

Common ground is an essential prerequisite for coordination in social interaction, including language use. When referring back to a referent in discourse, this referent is ‘given information’ and therefore in the interactants’ common ground. When a referent is being referred to for the first time, a speaker introduces ‘new information’. The analyses reported here are on gestures that accompany such references when they include definite and indefinite grammatical determiners. The main finding from these analyses is that referents referred to by definite and indefinite articles were equally often accompanied by gesture, but speakers tended to accompany definite references with gestures focusing on action information and indefinite references with gestures focusing on entity information. The findings suggest that speakers use speech and gesture together to design utterances appropriate for speakers with whom they share common ground.