Temporal Preparation for Speaking in Question-Answer Sequences

A Corpus Study on the Difference of Turn-Taking in Online Audio, Online Video, and Face-to-Face Conversation

Daily conversation is usually face-to-face and characterized by rapid and fluent exchange of turns between interlocutors. With the need to communicate across long distances, advances in communication media, online audio communication, and online video communication have become convenient alternatives for an increasing number of people. However, the fluency of turn-taking may be influenced when people communicate using these different modes. In this study, we conducted a corpus analysis of face-to-face, online audio, and online video conversations collected from the internet. The fluency of turn-taking in face-to-face conversations differed from that of online audio and video conversations. Namely, the timing of turn-taking was shorter and with more overlaps in face-to-face conversations compared with online audio and video conversations. This can be explained by the limited ability of online communication modes to transmit non-verbal cues and network latency. In addition, our study could not completely exclude the effect of formality of conversation. The present findings have implications for the rules of turn-taking in human online conversations, in that the traditional rule of no-gap-no-overlap may not be fully applicable to online conversations.

Information distribution patterns in naturalistic dialogue differ across languages

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).

The role of answer content and length when preparing answers to questions

Research suggests that interlocutors manage the timing demands of conversation by preparing what they want to say early. In three experiments, we used a verbal question-answering task to investigate what aspects of their response speakers prepare early. In all three experiments, participants answered more quickly when the critical content (here, barks) necessary for answer preparation occurred early (e.g., Which animal barks and is also a common household pet?) rather than late (e.g., Which animal is a common household pet and also barks?). In the individual experiments, we found no convincing evidence that participants were slower to produce longer answers, consisting of multiple words, than shorter answers, consisting of a single word. There was also no interaction between these two factors. A combined analysis of the first two experiments confirmed this lack of interaction, and demonstrated that participants were faster to answer questions when the critical content was available early rather than late and when the answer was short rather than long. These findings provide tentative evidence for an account in which interlocutors prepare the content of their answer as soon as they can, but sometimes do not prepare its length (and thus form) until they are ready to speak.

Visual bodily signals and conversational context benefit the anticipation of turn ends

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.

Estimating Systemic Cognitive States from a Mixture of Physiological and Brain Signals

As human-machine teams are being considered for a variety of mixed-initiative tasks, detecting and being responsive to human cognitive states, in particular systematic cognitive states, is among the most critical capabilities for artificial systems to ensure smooth interactions with humans and high overall team performance. Various human physiological parameters, such as heart rate, respiration rate, blood pressure, and skin conductance, as well as brain activity inferred from functional near-infrared spectroscopy or electroencephalogram, have been linked to different systemic cognitive states, such as workload, distraction, or mind-wandering among others. Whether these multimodal signals are indeed sufficient to isolate such cognitive states across individuals performing tasks or whether additional contextual information (e.g., about the task state or the task environment) is required for making appropriate inferences remains an important open problem. In this paper, we introduce an experimental and machine learning framework for investigating these questions and focus specifically on using physiological and neurophysiological measurements to learn classifiers associated with systemic cognitive states like cognitive load, distraction, sense of urgency, mind wandering, and interference. Specifically, we describe a multitasking interactive experimental setting used to obtain a comprehensive multimodal data set which provided the foundation for a first evaluation of various standard state-of-the-art machine learning techniques with respect to their effectiveness in inferring systemic cognitive states. While the classification success of these standard methods based on just the physiological and neurophysiological signals across subjects was modest, which is to be expected given the complexity of the classification problem and the possibility that higher accuracy rates might not in general be achievable, the results nevertheless can serve as a baseline for evaluating future efforts to improve classification, especially methods that take contextual aspects such as task and environmental states into account.

Hand Gestures Have Predictive Potential During Conversation: An Investigation of the Timing of Gestures in Relation to Speech

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.

Ultrasound measurements of interactive turn-taking in question-answer sequences: Articulatory preparation is delayed but not tied to the response

We know that speech planning in conversational turn-taking can happen in overlap with the previous turn and research suggests that it starts as early as possible, that is, as soon as the gist of the previous turn becomes clear. The present study aimed to investigate whether planning proceeds all the way up to the last stage of articulatory preparation (i.e., putting the articulators in place for the first phoneme of the response) and what the timing of this process is. Participants answered pre-recorded quiz questions (being under the illusion that they were asked live), while their tongue movements were measured using ultrasound. Planning could start early for some quiz questions (i.e., midway during the question), but late for others (i.e., only at the end of the question). The results showed no evidence for a difference between tongue movements in these two types of questions for at least two seconds after planning could start in early-planning questions, suggesting that speech planning in overlap with the current turn proceeds more slowly than in the clear. On the other hand, when time-locking to speech onset, tongue movements differed between the two conditions from up to two seconds before this point. This suggests that articulatory preparation can occur in advance and is not fully tied to the overt response itself.

Turn-taking in human face-to-face interaction is multimodal: gaze direction and manual gestures aid the coordination of turn transitions

Human communicative interaction is characterized by rapid and precise turn-taking. This is achieved by an intricate system that has been elucidated in the field of conversation analysis, based largely on the study of the auditory signal. This model suggests that transitions occur at points of possible completion identified in terms of linguistic units. Despite this, considerable evidence exists that visible bodily actions including gaze and gestures also play a role. To reconcile disparate models and observations in the literature, we combine qualitative and quantitative methods to analyse turn-taking in a corpus of multimodal interaction using eye-trackers and multiple cameras. We show that transitions seem to be inhibited when a speaker averts their gaze at a point of possible turn completion, or when a speaker produces gestures which are beginning or unfinished at such points. We further show that while the direction of a speaker's gaze does not affect the speed of transitions, the production of manual gestures does: turns with gestures have faster transitions. Our findings suggest that the coordination of transitions involves not only linguistic resources but also visual gestural ones and that the transition-relevance places in turns are multimodal in nature. This article is part of a discussion meeting issue 'Face2face: advancing the science of social interaction'.

Anticipatory Processing in a Verb-Initial Mayan Language: Eye-Tracking Evidence During Sentence Comprehension in Tseltal

We present a visual world eye-tracking study on Tseltal (a Mayan language) and investigate whether verbal information can be used to anticipate an upcoming referent. Basic word order in transitive sentences in Tseltal is Verb-Object-Subject (VOS). The verb is usually encountered first, making argument structure and syntactic information available at the outset, which should facilitate anticipation of the post-verbal arguments. Tseltal speakers listened to verb-initial sentences with either an object-predictive verb (e.g., "eat") or a general verb (e.g., "look for") (e.g., "Ya slo'/sle ta stukel on te kereme," Is eating/is looking (for) by himself the avocado the boy/ "The boy is eating/is looking (for) an avocado by himself") while seeing a visual display showing one potential referent (e.g., avocado) and three distractors (e.g., bag, toy car, coffee grinder). We manipulated verb type (predictive vs. general) and recorded participants' eye movements while they listened and inspected the visual scene. Participants' fixations to the target referent were analyzed using multilevel logistic regression models. Shortly after hearing the predictive verb, participants fixated the target object before it was mentioned. In contrast, when the verb was general, fixations to the target only started to increase once the object was heard. Our results suggest that Tseltal hearers pre-activate semantic features of the grammatical object prior to its linguistic expression. This provides evidence from a verb-initial language for online incremental semantic interpretation and anticipatory processing during language comprehension. These processes are comparable to the ones identified in subject-initial languages, which is consistent with the notion that different languages follow similar universal processing principles.

Deconstructing heterogeneity in schizophrenia through language: a semi-automated linguistic analysis and data-driven clustering approach

Previous works highlighted the relevance of automated language analysis for predicting diagnosis in schizophrenia, but a deeper language-based data-driven investigation of the clinical heterogeneity through the illness course has been generally neglected. Here we used a semiautomated multidimensional linguistic analysis innovatively combined with a machine-driven clustering technique to characterize the speech of 67 individuals with schizophrenia. Clusters were then compared for psychopathological, cognitive, and functional characteristics. We identified two subgroups with distinctive linguistic profiles: one with higher fluency, lower lexical variety but greater use of psychological lexicon; the other with reduced fluency, greater lexical variety but reduced psychological lexicon. The former cluster was associated with lower symptoms and better quality of life, pointing to the existence of specific language profiles, which also show clinically meaningful differences. These findings highlight the importance of considering language disturbances in schizophrenia as multifaceted and approaching them in automated and data-driven ways.

Prosodic cues in infant-directed speech facilitate young children's conversational turn predictions

Experienced language users are able to predict when conversational turns approach completion, which allows them to attend to and comprehend their interlocutor's speech while planning and accurately timing their response. Adults primarily rely on lexico-syntactic cues to make such predictions, but it remains unknown what cues support these predictions in young children whose lexico-syntactic competence is still developing. This study assessed children's reliance on prosodic cues, specifically when predicting conversational turn transitions in infant-directed speech (IDS), the speech register that they encounter in day-to-day interactions that is characterized by exaggerated prosody compared with adult-directed speech (ADS). Young children (1- and 3-year-olds) completed an anticipatory looking paradigm in which their gaze patterns were recorded while they observed conversations that were produced in IDS or ADS and that contained prosodically complete utterances (lexico-syntactic and prosodic cues) and prosodically incomplete utterances (only lexico-syntactic cues). The 1-year-olds anticipated more turns that were signaled by prosodic cues (i.e., prosodically complete utterances) only in IDS, whereas the 3-year-olds did so in both IDS and ADS. These findings indicate that children anticipate the completion of conversational turns by relying on prosodic information in speech and that the prosodic exaggeration of IDS supports this ability while children's linguistic and conversational skills are still developing.

Initiation of utterance planning in response to pre-recorded and "live" utterances

In everyday conversation, interlocutors often plan their utterances while listening to their conversational partners, thereby achieving short gaps between their turns. Important issues for current psycholinguistics are how interlocutors distribute their attention between listening and speech planning and how speech planning is timed relative to listening. Laboratory studies addressing these issues have used a variety of paradigms, some of which have involved using recorded speech to which participants responded, whereas others have involved interactions with confederates. This study investigated how this variation in the speech input affected the participants' timing of speech planning. In Experiment 1, participants responded to utterances produced by a confederate, who sat next to them and looked at the same screen. In Experiment 2, they responded to recorded utterances of the same confederate. Analyses of the participants' speech, their eye movements, and their performance in a concurrent tapping task showed that, compared with recorded speech, the presence of the confederate increased the processing load for the participants, but did not alter their global sentence planning strategy. These results have implications for the design of psycholinguistic experiments and theories of listening and speaking in dyadic settings.

Multimodal Language Processing in Human Communication

The natural ecology of human language is face-to-face interaction comprising the exchange of a plethora of multimodal signals. Trying to understand the psycholinguistic processing of language in its natural niche raises new issues, first and foremost the binding of multiple, temporally offset signals under tight time constraints posed by a turn-taking system. This might be expected to overload and slow our cognitive system, but the reverse is in fact the case. We propose cognitive mechanisms that may explain this phenomenon and call for a multimodal, situated psycholinguistic framework to unravel the full complexities of human language processing.

Representations of time in human frontoparietal cortex

Precise time estimation is crucial in perception, action and social interaction. Previous neuroimaging studies in humans indicate that perceptual timing tasks involve multiple brain regions; however, whether the representation of time is localized or distributed in the brain remains elusive. Using ultra-high-field functional magnetic resonance imaging combined with multivariate pattern analyses, we show that duration information is decoded in multiple brain areas, including the bilateral parietal cortex, right inferior frontal gyrus and, albeit less clearly, the medial frontal cortex. Individual differences in the duration judgment accuracy were positively correlated with the decoding accuracy of duration in the right parietal cortex, suggesting that individuals with a better timing performance represent duration information in a more distinctive manner. Our study demonstrates that although time representation is widely distributed across frontoparietal regions, neural populations in the right parietal cortex play a crucial role in time estimation.

Masamichi Hayashi et al. combine high field neuroimaging (7T fMRI) and multivariate pattern analyses to show that the pattern of functional MRI activity in the right parietal lobe can predict the perception of time in individual participants. They find that while time representation is distributed across frontoparietal regions, the right parietal cortex plays a key role.

Planning versus comprehension in turn-taking: Fast responders show reduced anticipatory processing of the question

Rapid response latencies in conversation suggest that responders start planning before the ongoing turn is finished. Indeed, an earlier EEG study suggests that listeners start planning their responses to questions as soon as they can (Bögels et al., 2015a). The present study aimed to (1) replicate this early planning effect and (2) investigate whether such early response planning incurs a cost on participants' concurrent comprehension of the ongoing turn. During the experiment participants answered questions from a confederate partner. To address aim (1), the questions were designed such that response planning could start either early or late in the turn. Our results largely replicate Bögels et al. (2015a), showing a large positive ERP effect and an oscillatory alpha/beta reduction right after participants could have first started planning their verbal response, again suggesting an early start of response planning. To address aim (2), the confederate's questions also contained either an expected word or an unexpected one to elicit a differential N400 effect, either before or after the start of response planning. We hypothesized an attenuated N400 effect after response planning had started. In contrast, the N400 effects before and after planning did not differ. There was, however, a positive correlation between participants' response time and their N400 effect size after planning had started; quick responders showed a smaller N400 effect, suggesting reduced attention to comprehension and possibly reduced anticipatory processing. We conclude that early response planning can indeed impact comprehension processing.

Next Speakers Plan Their Turn Early and Speak after Turn-Final "Go-Signals"

In conversation, turn-taking is usually fluid, with next speakers taking their turn right after the end of the previous turn. Most, but not all, previous studies show that next speakers start to plan their turn early, if possible already during the incoming turn. The present study makes use of the list-completion paradigm (Barthel et al., 2016), analyzing speech onset latencies and eye-movements of participants in a task-oriented dialogue with a confederate. The measures are used to disentangle the contributions to the timing of turn-taking of early planning of content on the one hand and initiation of articulation as a reaction to the upcoming turn-end on the other hand. Participants named objects visible on their computer screen in response to utterances that did, or did not, contain lexical and prosodic cues to the end of the incoming turn. In the presence of an early lexical cue, participants showed earlier gaze shifts toward the target objects and responded faster than in its absence, whereas the presence of a late intonational cue only led to faster response times and did not affect the timing of participants' eye movements. The results show that with a combination of eye-movement and turn-transition time measures it is possible to tease apart the effects of early planning and response initiation on turn timing. They are consistent with models of turn-taking that assume that next speakers (a) start planning their response as soon as the incoming turn's message can be understood and (b) monitor the incoming turn for cues to turn-completion so as to initiate their response when turn-transition becomes relevant.