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Introduction: In recent decades, interpersonal coordination and synchrony have been extensively examined in the field of psychology and cognitive science. Studies suggest that perceptual information enables interpersonal coordination and that perceptual noise may even enhance coordination. However, how these perceptual factors influence interpersonal coordination dynamics between head and body movements remains unclear. This study investigated the effect of visual information on the interpersonal coordination of head and body movements during dyadic conversations. Methods: The availability of visual information was manipulated by positioning a partition halfway between a pair of participants, and the conversations were recorded using a video camera. A video-based human pose estimation software (OpenPose) was used to quantify each interlocutor's head and body movements, which were submitted for cross-recurrence quantification analysis (CRQA), to assess the degree of coordination between the interlocutors. Results: The results showed different effects between head- and bodymovement coordination (i.e., a CRQA measure, maximum line length). The occlusion of visual information increased head-movement coordination, whereas it decreased body-movement coordination. Discussion: The results suggest that a distinct mechanism may be present at the head- and body-movement coordination level and this study observed differing appearances of compensatory behaviors. Further studies should be conducted to investigate the complex relationships between interpersonal coordination dynamics and various kinds of communication constraints, such as long-term or short-term, and lower-order (perceptual-motor) or higher-order (cognitivesocial) level constraints. [ABSTRACT FROM AUTHOR]

Objective: In social interactions, humans tend to naturally synchronize their body movements. We investigated interpersonal synchronization in conversations and examined its relationship with personality differences and post‐interaction appraisals. Method: In a 15‐minute semi‐structured conversation, 56 previously‐unfamiliar dyads introduced themselves, followed by self‐disclosing and argumentative conversations. Their bodily movements were video‐recorded in a standardized room (112 young adults, aged 18–33, mean = 20.54, SD = 2.74; 58% Dutch, 31% German, 11% other). Interpersonal bodily synchronization was estimated as (a) synchronization strength using Windowed Lagged Cross‐Correlations and (b) Dynamic Organization (Determinism/Entropy/Laminarity/Mean Line) using Cross‐Recurrence Quantification Analysis. Bodily synchronization was associated with differences in Agreeableness and Extraversion (IPIP‐NEO‐120) and post‐conversational appraisals (affect/closeness/enjoyment) in mixed‐effect models. Results: Agreeable participants exhibited higher complexity in bodily synchronization dynamics (higher Entropy) than disagreeable individuals, who also reported more negative affect afterward. Interpersonal synchronization was stronger among extroverts than among introverts and extroverts appraised conversations as more positive and enjoyable. Bodily synchronization strength and dynamic organization were related to the type of conversation (self‐disclosing/argumentative). Conclusions: Interpersonal dynamics were intimately connected to differences in Agreeableness and Extraversion, varied across situations, and these parameters affected how pleasant, close, and enjoyable each conversation felt. [ABSTRACT FROM AUTHOR]

Professional hand percussionists who play the darbuka (a drum from the Middle East) show fast and stable bimanual finger coordination compared to amateur players. A cross-recurrence quantification analysis clarifies how stable bimanual coordination is achieved by dissociating stochastic noise and attractor strength in the dynamic system. This study employed a cross-recurrence quantification analysis to examine professional and amateur darbuka players' fast and stable bimanual finger coordination. Eight professional and eight amateur percussion players participated in the study and played a darbuka with their right and left ring fingers, alternating as fast as possible for 12 s. We then analyzed the finger position data and calculated the stochastic noise and attractor strength from the density and the longest diagonal line in the recurrence plot, respectively. We used linear mixed-effects models to test whether stochastic noise and attractor strength differed between professional and amateur players. The results indicate that professional darbuka players achieve fast and stable bimanual finger coordination by enhancing attractor strength rather than reducing stochastic noise in the dynamic system. [ABSTRACT FROM AUTHOR]

This paper presents a new Dynamic Recurrence Index (DRI) to detect the occurrence and quantify the evolution of oil whirl instability in the rotor-journal bearing system by measuring the dynamical similarity between the normal working condition and unstable operating states of the system. In this method, two signals, one normal operating condition signal as the reference signal and one unstable operating condition signal, are reconstructed into the same phase space before the Cross-Recurrence Plots (CRP) are prepared. Then, the structure of these CRPs is analyzed by applying the Cross-Recurrence Quantification Analysis (CRQA) to estimate the dynamical difference between the normal operating condition and unstable operating states of the rotor-journal bearing system. Finally, those CRQA variables are mapped by Support Vector Data Description (SVDD) into a dynamic recurrence index to monitor the evolution and evaluate the severity degree of the oil whirl instability. The simulation and experimental results show that the CRQA variables and DRI are sensitive to the occurrence of oil whirl instability, and the proposed method is a practical approach to monitoring the oil whirl instability for the rotor-journal bearing system. [ABSTRACT FROM AUTHOR]

Humans, as social beings, are capable of employing variousbehavioral cues, such as gaze, speech, manual action, and bodyposture, in everyday communication. However, to extract fine-grained interaction patterns in social contexts has beenpresented with methodological challenges. Cross-RecurrencePlot Quantification Analysis (CRQA) is an analysis methodinvented in theoretical physics and recently applied tocognitive science to study interpersonal coordination. In thispaper, we extend this approach to analyzing joint activities inchild-parent interaction. We define a new representation asCross Recurrence Block based on CRQA. With thisrepresentation, we are able to capture interpersonal dynamicsfrom more than two behavioral streams in one CrossRecurrence Plot and derive a suite of measures to quantifydetailed characteristics of coordination. Using a datasetcollected from a child-parent interaction study, we show thatthese quantitative measures of joint activities revealdevelopmental changes in coordinative behavioral patternsbetween children and parents.

We explored the social synchronization of gaze‐shift behaviors when responding to joint attention in children with autism spectrum disorder (ASD). Forty‐one children aged 5 to 8 with ASD and 43 typically developing (TD) children watched a video to complete the response to joint attention (RJA) tasks, during which their gaze data were collected. The synchronization of gaze‐shift behaviors between children and the female model in the video was measured with the cross‐recurrence quantification analysis (CRQA). Ultimately, we discovered that children with ASD had the ability to synchronize their gaze shifts with the female model in the video during RJA tasks. Compared to the TD children, they displayed lower levels of synchronization and longer latency in this synchronized behavior. These findings provide a new avenue to deepen our understanding of the impairments of social interaction in children with ASD. Notably, the analytic method can be further applied to explore the social synchronization of numerous other social interactive behaviors in ASD. Lay Summary: This study explored how autistic children synchronized their gazed shifts with others' gaze cues during joint attention. We found that compared to typical children, autistic children synchronized their gazed shifts less and needed more time to follow others' gaze. These findings provide a new avenue to deepen our understanding of the impairments of social interaction in children with ASD. [ABSTRACT FROM AUTHOR]

Despite the growing consensus that the majority of psychological phenomena at work are temporally embedded and highly dynamic, existing research is often based on simplified theoretical and methodological models, which take limited account of process dynamics and especially non-linear growth trajectories. In this paper, we highlight the potentials of using recurrence quantifications analysis (RQA) and an extension of RQA – cross-recurrence quantification analysis (CRQA) – for researching process dynamics in organizations. (C)RQA is a powerful technique that can be used to both visualize and quantify time-series data such as repeated measurements of psychological states or sequentially coded dyadic and team interactions. To illustrate the manifold opportunities of (C)RQA, we present three application examples focusing on individuals as systems, dyads as systems, and teams as systems. Specifically, we highlight how (C)RQA can be applied to individual diary data, to leader-follower communication dynamics observed during annual appraisal interviews, and to high-density coded team interactions observed during organizational meetings. We discuss the strengths and limitations of (C)RQA and provide recommendations for researchers interested in using the method. [ABSTRACT FROM AUTHOR]

In the current study, we applied the dynamical systems approach to obtain novel insights into resilience losses. Dyads (n = 42) performed a lateral rhythmical pointing (Fitts) task. To induce resilience losses and transitions in performance, dyads were exposed to ascending and descending scoring scenarios. To assess changes in the complexity of the dyadic pointing performance, reflecting their resilience, we performed cross-recurrence quantification analyses. Then, we tested for temporal patterns indicating resilience losses. We applied lag 1 autocorrelations to assess critical slowing down and mean squared successive differences (MSSD) to assess critical fluctuations. Although we did not find evidence that scoring scenarios produce performance transitions across individuals, we did observe transitions in each condition. Contrary to the lag 1 autocorrelations, our results suggest that transitions in human performance are signaled by increases in the MSSD. Specifically, both positive and negative performance transitions were accompanied with increased fluctuations in performance. Furthermore, negative performance transitions were accompanied with increased fluctuations of complexity, signaling resilience losses. On the other hand, complexity remained stable for positive performance transitions. Together, these results suggest that combining information of critical fluctuations in performance and complexity can predict both positive and negative tra nsitions in dyadic team performance. [ABSTRACT FROM AUTHOR]

Background: Dog‐assisted therapy (DAT) is hypothesized to help children with autism spectrum disorder (ASD) and Down syndrome (DS). Methods: The present authors compared synchronous movement patterns of these children (n = 10) and their therapy dogs during the first and last session of a DAT programme, and their post‐therapy changes in emotional and behavioural problems. Results: The present authors found a significant increase in synchrony between child and therapy dog over time. Exploratory analyses suggest more synchrony between children with ASD and their therapy dogs, compared to the children with DS. Conclusions: This study is the first to test the synchrony hypothesis, shedding light upon a mechanism that may underlie the effect of DAT and how this may be different for children with ASD and DS. [ABSTRACT FROM AUTHOR]

Interpersonal human-human interaction is a dynamical exchange and coordination of social signals, feelings and emotions usually performed through and across multiple modalities such as facial expressions, gestures, and language. Developing machines able to engage humans in rich and natural interpersonal interactions requires capturing such dynamics. This paper addresses primitive emotional contagion during dyadic interactions in which roles are prefixed. Primitive emotional contagion was defined as the tendency people have to automatically mimic and synchronize their multimodal behavior during interactions and, consequently, to emotionally converge. To capture emotional contagion, a cross-recurrence based methodology that explicitly integrates short and long-term temporal dynamics through the analysis of both facial expressions and sentiment was developed. This approach is employed to assess emotional contagion at unimodal, multimodal and cross-modal levels and is evaluated on the Solid SAL-SEMAINE corpus. Interestingly, the approach is able to show the importance of the adoption of cross-modal strategies for addressing emotional contagion. [ABSTRACT FROM AUTHOR]

Pupil size fluctuations during stationary scotopic conditions may convey information about the cortical state activity at rest. An important link between neuronal network state modulation and pupil fluctuations is the cholinergic and noradrenergic neuromodulatory tone, which is active at cortical level and in the peripheral terminals of the autonomic nervous system (ANS). This work aimed at studying the low- and high-frequency coupled oscillators in the autonomic spectrum (0–0.45 Hz) which, reportedly, drive the spontaneous pupillary fluctuations. To assess the interaction between the oscillators, we focused on the patterns of their trajectories in the phase-space. Firstly, the frequency spectrum of the pupil signal was determined by empirical mode decomposition. Secondly, cross-recurrence quantification analysis was used to unfold the non-linear dynamics. The global and local patterns of recurrence of the trajectories were estimated by two parameters: determinism and entropy. An elliptic region in the entropy-determinism plane (95% prediction area) yielded health-related values of entropy and determinism. We hypothesize that the data points inside the ellipse would likely represent balanced activity in the ANS. Interestingly, the Epworth Sleepiness Scale scores scaled up along with the entropy and determinism parameters. Although other non-linear methods like Short Time Fourier Transform and wavelets are usually applied for analyzing the pupillary oscillations, they rely on strong assumptions like the stationarity of the signal or the a priori knowledge of the shape of the single basis wave. Instead, the cross-recurrence analysis of the non-linear dynamics of the pupil size oscillations is an adaptable diagnostic tool for identifying the different weight of the autonomic nervous system components in the modulation of pupil size changes at rest in non-luminance conditions.

Pupil size fluctuations during stationary scotopic conditions may convey information about the cortical state activity at rest. An important link between neuronal network state modulation and pupil fluctuations is the cholinergic and noradrenergic neuromodulatory tone, which is active at cortical level and in the peripheral terminals of the autonomic nervous system (ANS). This work aimed at studying the low- and high-frequency coupled oscillators in the autonomic spectrum (0–0.45 Hz) which, reportedly, drive the spontaneous pupillary fluctuations. To assess the interaction between the oscillators, we focused on the patterns of their trajectories in the phase-space. Firstly, the frequency spectrum of the pupil signal was determined by empirical mode decomposition. Secondly, cross-recurrence quantification analysis was used to unfold the non-linear dynamics. The global and local patterns of recurrence of the trajectories were estimated by two parameters: determinism and entropy. An elliptic region in the entropy-determinism plane (95% prediction area) yielded health-related values of entropy and determinism. We hypothesize that the data points inside the ellipse would likely represent balanced activity in the ANS. Interestingly, the Epworth Sleepiness Scale scores scaled up along with the entropy and determinism parameters. Although other non-linear methods like Short Time Fourier Transform and wavelets are usually applied for analyzing the pupillary oscillations, they rely on strong assumptions like the stationarity of the signal or the a priori knowledge of the shape of the single basis wave. Instead, the cross-recurrence analysis of the non-linear dynamics of the pupil size oscillations is an adaptable diagnostic tool for identifying the different weight of the autonomic nervous system components in the modulation of pupil size changes at rest in non-luminance conditions. [ABSTRACT FROM AUTHOR]

This paper provides a practical, hands-on introduction to cross-recurrence quantification analysis (CRQA), diagonal cross-recurrence profiles (DCRP), and multidimensional recurrence quantification analysis (MdRQA) in R. These methods have enjoyed increasing popularity in the cognitive and social sciences since a recognition that many behavioral and neurophysiological processes are intrinsically time dependent and reliant on environmental and social context has emerged. Recurrence-based methods are particularly suited for time-series that are non-stationary or have complicated dynamics, such as longer recordings of continuous physiological or movement data, but are also useful in the case of time-series of symbolic data, as in the case of text/verbal transcriptions or categorically coded behaviors. In the past, they have been used to assess changes in the dynamics of, or coupling between physiological and behavioral measures, for example in joint action research to determine the co-evolution of the behavior between individuals in dyads or groups, or for assessing the strength of coupling/correlation between two or more time-series. In this paper, we provide readers with a conceptual introduction, followed by a step-by-step explanation on how the analyses are performed in R with a summary of the current best practices of their application.

Tightly coordinated grip force adaptations in response to changing load forces have been reported as continuous, stable, and proportional to the load force changes. Considering the existence of inherent sensorimotor feedback delays, current accounts of grip force-load force coupling invoke explicit predictive mechanisms in the form of internal models for feedforward control to account for anticipatory grip force modulations. However, recent findings suggest that the stability and regularity of grip force-load force coupling is less persistent than previously thought. Thus, the objective of the current study was to comprehensively quantify the time-varying characteristics of grip force-load force coupling. Investigations into the coupling’s dynamics during continuous 30 s bouts of load force oscillation revealed intermittent phases of coordination, as well as phases that varied in stability, rather than a persistent and continuously stable pattern of coordination. These findings have important implications for accounts of grip force-load force coupling and of anticipation in motor control, more broadly. [ABSTRACT FROM AUTHOR]

When dealing with semi-supervised scenarios, the Positive and Unlabeled (PU) problem is a special case in which few labeled examples from a single class of interest are received to proceed with the classification of unseen instances, according to their similarities with the known class. In the scope of time series, most of the current studies propose to address this subject using a self-training approach based on the 1-Nearest Neighbor algorithm. In order to compute the most similar instance, they compare features along the time domain using the Euclidean Distance and the Dynamic Time Warping-Delta. Despite time-domain measurements permit the analysis of local series shapes, they disconsider temporal recurrences commonly found in natural phenomena (e.g. population growth, climate studies) and are more sensitive to local noise and fluctuations, leading to poor classification performances as confirmed in this paper. This drawback motivated us to propose the use of the Maximum Diagonal Line of the Cross-Recurrence Quantification Analysis (MDL-CRQA), applied on the time series phase space, as similarity measurement. The phase space is obtained after applying Takens embedding theorem on the series, unfolding temporal relationships and dependencies among data observations. As consequence, by comparing phase spaces rather than the series themselves, we can assess how their trajectories evolve along time, including their periodicities and temporal cycles, as well as decreasing noise influences. Experimental results confirm MDL-CRQA improves classification results for PU time series when compared against the mostly used time-domain similarity measurements. [ABSTRACT FROM AUTHOR]

In the weaning period, infants are introduced to solid food after being fed solely on milk, which involves a deliberate reorganization of the infant-caregiver feeding interaction. This multiple case study, involving 5 dyads with 10 repeated observations, analyzed its dynamical structure using Cross-Recurrence Quantification Analysis. The results showed that an optimal interaction occurs when the caregiver is leading by roughly 1-2 seconds. During the weaning period, all dyads showed signs of increased synchronization, although there are interesting differences between dyads. These findings indicate that infant-caregiver dyads co-regulate their behavior within a relatively short period. [ABSTRACT FROM AUTHOR]

Much work on communication and joint action conceptualizes interaction as a dynamical system. Under this view, dynamic properties of interaction should be shaped by the context in which the interaction is taking place. Here we explore interpersonal movement coordination or synchrony—the degree to which individuals move in similar ways over time—as one such context-sensitive property. Studies of coordination have typically investigated how these dynamics are influenced by either high-level constraints (i.e., slow-changing factors) or low-level constraints (i.e., fast-changing factors like movement). Focusing on nonverbal communication behaviors during naturalistic conversation, we analyzed how interacting participants' head movement dynamics were shaped simultaneously by high-level constraints (i.e., conversation type; friendly conversations vs. arguments) and low-level constraints (i.e., perceptual stimuli; non-informative visual stimuli vs. informative visual stimuli). We found that high- and low-level constraints interacted non-additively to affect interpersonal movement dynamics, highlighting the context sensitivity of interaction and supporting the view of joint action as a complex adaptive system.

Rhythmicity characterizes both interpersonal synchrony and spoken language. Emotions and language are forms of interpersonal communication, which interact with each other throughout development. We investigated whether and how emotional synchrony between mothers and their 9-month-old infants relates to infants' word segmentation as an early marker of language development. Twenty-six 9-month-old infants and their German-speaking mothers took part in the study. To measure emotional synchrony, we coded positive, neutral and negative emotional expressions of the mothers and their infants during a free play session. We then calculated the degree to which the mothers' and their infants' matching emotional expressions followed a predictable pattern. To measure word segmentation, we familiarized infants with auditory text passages and tested how long they looked at the screen while listening to familiar versus novel words. We found that higher levels of predictability (i.e. low entropy) during mother-infant interaction is associated with infants' word segmentation performance. These findings suggest that individual differences in word segmentation relate to the complexity and predictability of emotional expressions during mother-infant interactions. [ABSTRACT FROM AUTHOR]

This paper describes the R package crqa to perform cross-recurrence quantification analysis of two time series of either a categorical or continuous nature. Streams of behavioral information, from eye movements to linguistic elements, unfold over time. When two people interact, such as in conversation, they often adapt to each other, leading these behavioral levels to exhibit recurrent states. In dialogue, for example, interlocutors adapt to each other by exchanging interactive cues: smiles, nods, gestures, choice of words, and so on. In order for us to capture closely the goings-on of dynamic interaction, and uncover the extent of coupling between two individuals, we need to quantify how much recurrence is taking place at these levels. Methods available in crqa would allow researchers in cognitive science to pose such questions as how much are two people recurrent at some level of analysis, what is the characteristic lag time for one person to maximally match another, or whether one person is leading another. First, we set the theoretical ground to understand the difference between ‘correlation’ and ‘co-visitation’ when comparing two time series, using an aggregative or cross-recurrence approach. Then, we describe more formally the principles of cross-recurrence, and show with the current package how to carry out analyses applying them. We end the paper by comparing computational efficiency, and results’ consistency, of crqa R package, with the benchmark MATLAB toolbox crptoolbox (Marwan, 2013). We show perfect comparability between the two libraries on both levels.

The present study investigated how constraining movement affects interpersonal coordination and joint cognitive performance. Pairs of participants worked cooperatively to solve picture-puzzle tasks in which they conversed to identify differences between pictures in 3 degree-of-constraint conditions: both participants were free to move their hands (free-free; FF); both participants' hands were restrained (restrained-restrained; RR); and the hands of 1 participant were free while the hands of the other participant were restrained (free-restrained; FR). Eye tracking data were collected, and movement was measured at the waist, hand, and head. Data were analyzed using Cross-Recurrence Quantification Analysis (CRQ). Postural sway coordination, gaze coordination, and task performance were predicted to be highest in FF, followed by RR, and then by FR. Results showed the asymmetric FR condition generally exhibited lesser degrees of coordination than the symmetric Conditions FF and RR, and that the patterning of coordination in the symmetric conditions varied across the measured body segments. These results demonstrate that movement restraints affect not only interpersonal postural coordination, but also joint attention. Additionally, significant positive relationships were found between task performance and total amount of anterior-posterior movement measured at the head, hand and waist; number of utterances; and number of differences pairs found in the puzzles. These findings indicate a relationship between movement and task performance consistent with the hypotheses that both interpersonal coordination and cognitive performance are sensitive to local action constraints. [ABSTRACT FROM AUTHOR]

We present the perspective that interpersonal movement coordination results from establishing interpersonal synergies. Interpersonal synergies are higher-order control systems formed by coupling movement system degrees of freedom of two (or more) actors. Characteristic features of synergies identified in studies of intrapersonal coordination—dimensional compression and reciprocal compensation—are revealed in studies of interpersonal coordination that applied the uncontrolled manifold approach and principal component analysis to interpersonal movement tasks. Broader implications of the interpersonal synergy approach for movement science include an expanded notion of mechanism and an emphasis on interaction-dominant dynamics.

Abstract: Athletes who sustain non-contact anterior cruciate ligament (ACL) injuries and undergo surgical reconstruction exhibit deficits in sensorimotor control, which often impairs lower-limb movement coordination. The purpose of this experiment was to measure the influence of sensorimotor deficits on the ankle–hip coordination of a postural coordination task in athletes following ACL reconstruction. Twenty-two female athletes who were cleared to return to sports participation following ACL reconstruction and 22 uninjured female athletes performed a unilateral dynamic postural rhythmic coordination task at two movement frequencies (0.2 and 0.7Hz). Athletes with ACL-reconstruction exhibited greater ankle–hip relative phase variability and reduced regularity of coupling than uninjured athletes, especially during the 0.2Hz condition. The results of this study show altered lower extremity coordination patterns in athletes following ACL reconstruction and return to sports participation. The results also indicate that dynamical coordination measures may provide objective measures of sensorimotor deficits following ACL reconstruction and can potentially guide rehabilitation interventions following reconstruction. [Copyright &y& Elsevier]

Abstract: In recent years, research in the field of social interactions has focused on the exploration of the coordinative structures that substantiate joint task performance. The current project explores whether interpersonal coordination during joint task performance gives rise to a joint coordinative structure across individuals, and whether such coordinative structures are affected by task demands. Principal component analysis (PCA) is used to identify relevant interpersonal and intrapersonal coordinative modes for the single and joint performance of a supra-postural task, which varied along its precision and role demands. In addition, cross-recurrence quantification analysis (CRQA) was combined with PCA in order to quantify the degree and stability of interpersonal coordination across intrapersonal coordinative modes. Results indicate that the composition and number of coordinative modes varied for joint compared to single performance, and that interpersonal coordination across the first coordinative mode increased in degree and stability for joint compared to single performance. Overall, these findings indicate that joint coordinative structures are affected by the nature of the task performed and the constraints it places on joint and single performance. [Copyright &y& Elsevier]

Abstract: Ballet dancers have heightened balance skills, but previous studies that compared dancers to non-dancers have not quantified patterns of multi-joint postural coordination. This study utilized a visual tracking task that required professional ballet dancers and untrained control participants to sway with the fore–aft motion of a target while standing on one leg, at target frequencies of 0.2 and 0.6Hz. The mean and variability of relative phase between the ankle and hip, and measures from cross-recurrence quantification analysis (i.e., percent cross-recurrence, percent cross-determinism, and cross-maxline), indexed the coordination patterns and their stability. Dancers exhibited less variable ankle–hip coordination and a less deterministic ankle–hip coupling, compared to controls. The results indicate that ballet dancers have increased coordination stability, potentially achieved through enhanced neuromuscular control and/or perceptual sensitivity, and indicate proficiency at optimizing the constraints that enable dancers to perform complex balance tasks. [Copyright &y& Elsevier]

Abstract: The performance of signalized arterials is related to queuing phenomena. The paper investigates the effect of transitional traffic flow conditions imposed by the formation and dissipation of queues. A cross-recurrence quantification analysis combined with Bayesian augmented networks are implemented to reveal the prevailing statistical characteristics of the short-term traffic flow patterns under the effect of transitional queue conditions. Results indicate that transitions between free-flow conditions, critical queue conditions that exceed the detector’s length, as well as the occurrence of spillovers impose a set of prevailing traffic flow patterns with different statistical characteristics with respect to determinism, nonlinearity, non-stationarity and laminarity. The complexity in critical queue conditions is further investigated by introducing two supplementary regions in the critical area before spillover occurrence. Results indicate that the supplementary information on the transitional conditions in the critical area increases the accuracy of the predictive relations between the statistical characteristics of traffic flow evolution and the occurrence of transitions. [Copyright &y& Elsevier]

We explored the social synchronization of gaze-shift behaviors when responding to joint attention in children with autism spectrum disorder (ASD). Forty-one children aged 5 to 8 with ASD and 43 typically developing (TD) children watched a video to complete the response to joint attention (RJA) tasks, during which their gaze data were collected. The synchronization of gaze-shift behaviors between children and the female model in the video was measured with the cross-recurrence quantification analysis (CRQA). Ultimately, we discovered that children with ASD had the ability to synchronize their gaze shifts with the female model in the video during RJA tasks. Compared to the TD children, they displayed lower levels of synchronization and longer latency in this synchronized behavior. These findings provide a new avenue to deepen our understanding of the impairments of social interaction in children with ASD. Notably, the analytic method can be further applied to explore the social synchronization of numerous other social interactive behaviors in ASD. LAY SUMMARY: This study explored how autistic children synchronized their gazed shifts with others' gaze cues during joint attention. We found that compared to typical children, autistic children synchronized their gazed shifts less and needed more time to follow others' gaze. These findings provide a new avenue to deepen our understanding of the impairments of social interaction in children with ASD., (© 2021 International Society for Autism Research and Wiley Periodicals LLC.)