Robin N. Salesse

Difficulty leading interpersonal coordination: towards an embodied signature of social anxiety disorder

Defined by a persistent fear of embarrassment or negative evaluation while engaged in social interaction or public performance, social anxiety disorder (SAD) is one of the most common psychiatric syndromes. Previous research has made a considerable effort to better understand and assess this mental disorder. However, little attention has been paid to social motor behavior of patients with SAD despite its crucial importance in daily social interactions. Previous research has shown that the coordination of arm, head or postural movements of interacting people can reflect their mental states or feelings such as social connectedness and social motives, suggesting that interpersonal movement coordination may be impaired in patients suffering from SAD. The current study was specifically aimed at determining whether SAD affects the dynamics of social motor coordination. We compared the unintentional and intentional rhythmic coordination of a SAD group (19 patients paired with control participants) with the rhythmic coordination of a control group (19 control pairs) in an interpersonal pendulum coordination task. The results demonstrated that unintentional social motor coordination was preserved with SAD while intentional coordination was impaired. More specifically, intentional coordination became impaired when patients with SAD had to lead the coordination as indicated by poorer (i.e., more variable) coordination. These differences between intentional and unintentional coordination as well as between follower and leader roles reveal an impaired coordination dynamics that is specific to SAD, and thus, opens promising research directions to better understand, assess and treat this mental disorder.

Social motor coordination in unaffected relatives of schizophrenia patients: a potential intermediate phenotype.

Intermediate endophenotypes emerge as an important concept in the study of schizophrenia. Although research on phenotypes mainly investigated cognitive, metabolic or neurophysiological markers so far, some authors also examined the motor behavior anomalies as a potential trait-marker of the disease. However, no research has investigated social motor coordination despite the possible importance of its anomalies in schizophrenia. The aim of this study was thus to determine whether coordination modifications previously demonstrated in schizophrenia are trait-markers that might be associated with the risk for this pathology. Interpersonal motor coordination in 27 unaffected first-degree relatives of schizophrenia patients and 27 healthy controls was assessed using a hand-held pendulum task to examine the presence of interpersonal coordination impairments in individuals at risk for the disorder. Measures of neurologic soft signs, clinical variables and neurocognitive functions were collected to assess the cognitive and clinical correlates of social coordination impairments in at-risk relatives. After controlling for potential confounding variables, unaffected relatives of schizophrenia patients had impaired intentional interpersonal coordination compared to healthy controls while unintentional interpersonal coordination was preserved. More specifically, in intentional coordination, the unaffected relatives of schizophrenia patients exhibited coordination patterns that had greater variability and in which relatives did not lead the coordination. These results show that unaffected relatives of schizophrenia patients, like the patients themselves, also present deficits in intentional interpersonal coordination. For the first time, these results suggest that intentional interpersonal coordination impairments might be a potential motor intermediate endophenotype of schizophrenia opening new perspectives for early diagnosis.

The acquisition of socio-motor improvisation in the mirror game

Socio-motor improvisation is defined as the creative action of two or more people without a script or anticipated preparation. It is evaluated through two main parameters: movement synchronization and movement richness. Experts in art (e.g., dance, theater or music) are known to exhibit higher synchronization and to perform richer movements during interpersonal improvisation, but how these competences evolve over time is largely unknown. In the present study, we investigated whether performing more synchronized and richer movements over time can promote the acquisition of improvisation. Pairs of novice participants were instructed to play an improvisation mirror game in three different sessions. Between sessions, they performed an unintended interpersonal coordination task in which synchronization and richness were manipulated, resulting in four different groups of dyads. Our results demonstrate that synchronization during improvisation improved for all groups whereas movement richness only enhanced for dyads that performed synchronized movements during unintended coordination tasks. Our findings suggest that movement synchrony contributes more than movement richness to the acquisition of socio-motor improvisation in the mirror game.

Nonverbal expressive behaviour in schizophrenia and social phobia.

Expressive behaviour plays a crucial role in the success of social interactions. Abnormality of expressive behaviour has been reported in interpersonal interactions of patients suffering from schizophrenia and social phobia, two debilitating mental disorders with important social deficits. However, no study has compared the expressive behaviour in these two disorders. Thirty schizophrenia patients, 21 social phobia patients and 30 healthy controls were evaluated and compared on expressive, cognitive and clinical dimensions. Expressive behaviour was assessed using the Motor Affective subscale of the Motor-Affective-Social-Scale (MASS). Covariables include the Positive and Negative Syndrome Scale (PANSS), the anxiety level Liebowitz-Social-Anxiety-Scale (LSAS) and cognitive tasks. After controlling for depression, schizophrenia and social phobia patients both exhibited significantly fewer expressive behaviours compared to healthy controls. Moreover, our results showed specific signatures: schizophrenia patients performed fewer spontaneous gestures (hand gestures and smiles) whereas social phobia patients had an impaired ability to produce voluntary smiles in comparison to healthy controls. Interestingly, poor social functioning was significantly correlated with a decrease of expressive behaviour for schizophrenia patients. Expressive behaviour is impaired in different ways in social phobia and schizophrenia and is associated in schizophrenia with poorer social functioning. The Motor Affective subscale of the MASS is an interesting tool for assessing the dysfunction of interpersonal expressive behaviour in mental disorders.

Unravelling socio-motor biomarkers in schizophrenia

We present novel, low-cost and non-invasive potential diagnostic biomarkers of schizophrenia. They are based on the ‘mirror-game’, a coordination task in which two partners are asked to mimic each other’s hand movements. In particular, we use the patient’s solo movement, recorded in the absence of a partner, and motion recorded during interaction with an artificial agent, a computer avatar or a humanoid robot. In order to discriminate between the patients and controls, we employ statistical learning techniques, which we apply to nonverbal synchrony and neuromotor features derived from the participants’ movement data. The proposed classifier has 93% accuracy and 100% specificity. Our results provide evidence that statistical learning techniques, nonverbal movement coordination and neuromotor characteristics could form the foundation of decision support tools aiding clinicians in cases of diagnostic uncertainty.Mirror game test could detect schizophreniaA new test of movement and social interaction could detect markers of schizophrenia, and help to diagnose and manage the condition. In an effort to establish reliable indicators of schizophrenia, Piotr Slowinski at the University of Exeter, UK and colleagues developed a test that could detect deficits in movement and social interactions, both characteristics of the disorder. They asked people to perform movements alone, and to mirror the movements of a computer avatar or a humanoid robot. Automated analysis of the movements allowed to distinguish people with schizophrenia from healthy participants with accuracy and specificity slightly better than clinical interviews and comparable to test based on much more expensive neuroimaging methods. The technique could help with diagnosis of schizophrenia and to monitor patients’ responses to treatment, but needs to be tested in clinical trials before being applied in clincal practice.

Interaction patterns and individual dynamics shape the way we move in synchrony

An important open problem in Human Behaviour is to understand how coordination emerges in human ensembles. This problem has been seldom studied quantitatively in the existing literature, in contrast to situations involving dual interaction. Here we study motor coordination (or synchronisation) in a group of individuals where participants are asked to visually coordinate an oscillatory hand motion. We separately tested two groups of seven participants. We observed that the coordination level of the ensemble depends on group homogeneity, as well as on the pattern of visual couplings (who looked at whom). Despite the complexity of social interactions, we show that networks of coupled heterogeneous oscillators with different structures capture well the group dynamics. Our findings are relevant to any activity requiring the coordination of several people, as in music, sport or at work, and can be extended to account for other perceptual forms of interaction such as sound or feel.

Postural Coordination during Socio-motor Improvisation

Human interaction often relies on socio-motor improvisation. Creating unprepared movements during social interaction is not a random process but relies on rules of synchronization. These situations do not only involve people to be coordinated, but also require the adjustment of their posture in order to maintain balance and support movements. The present study investigated posture in such a context. More precisely, we first evaluated the impact of amplitude and complexity of arm movements on posture in solo situation. Then, we assessed the impact of interpersonal coordination on posture using the mirror game in which dyads performed improvised and synchronized movements (i.e., duo situation). Posture was measured through ankle-hip coordination in medio-lateral and antero-posterior directions (ML and AP respectively). Our results revealed the spontaneous emergence of in-phase pattern in ML direction and antiphase pattern in AP direction for solo and duo situations. These two patterns respectively refer to the simultaneous flexion/extension of the ankles and the hips in the same or opposite direction. It suggests different functional roles of postural coordination patterns in each direction, with in-phase supporting task performance in ML (dynamical stability) and antiphase supporting postural control in AP (mechanical stability). Although amplitude of movement did not influence posture, movement complexity disturbed postural stability in both directions. Conversely, interpersonal coordination promoted postural stability in ML but not in AP direction. These results are discussed in terms of the difference in coupling strength between ankle-hip coordination and interpersonal coordination.

Self-Face Recognition in Schizophrenia: An Eye-Tracking Study

Self-face recognition has been shown to be impaired in schizophrenia (SZ), according to studies using behavioral tasks implicating cognitive demands. Here, we employed an eye-tracking methodology, which is a relevant tool to understand impairments in self-face recognition deficits in SZ because it provides a natural, continuous and online record of face processing. Moreover, it allows collecting the most relevant and informative features each individual looks at during the self-face recognition. These advantages are especially relevant considering the fundamental role played by the patterns of visual exploration on face processing. Thus, this paper aims to investigate self-face recognition deficits in SZ using eye-tracking methodology. Visual scan paths were monitored in 20 patients with SZ and 20 healthy controls. Self, famous, and unknown faces were morphed in steps of 20%. Location, number, and duration of fixations on relevant areas were recorded with an eye-tracking system. Participants performed a passive exploration task (no specific instruction was provided), followed by an active decision making task (individuals were explicitly requested to recognize the different faces). Results showed that patients with SZ had fewer and longer fixations compared to controls. Nevertheless, both groups focused their attention on relevant facial features in a similar way. No significant difference was found between groups when participants were requested to recognize the faces (active task). In conclusion, using an eye tracking methodology and two tasks with low levels of cognitive demands, our results suggest that patients with SZ are able to: (1) explore faces and focus on relevant features of the face in a similar way as controls; and (2) recognize their own face.

Movement similarities and differences during social interaction: The scientific foundation of the ALTEREGO European project

Schizophrenia, autism, or social phobia are typically accompanied by social interaction deficits. The objective of the AlterEgo European project is the creation of an interactive cognitive architecture, implementable in various artificial agents, allowing a continuous interaction with patients suffering from social disorders by virtue of changes in behavioral (robot-based) as well as morphological (avatar-based) properties of that agent. Here we present the scientific foundations of the project and its four main experimental steps. The results of the first similarity experiments are reported, which show that healthy participants functionally adapt their social motor interaction when they interact with agents (real or artificial) morphologically and behaviorally similar to, or different from, them. These results obtained with healthy participants have consequences for the rehabilitation of socially deficient patients.

Standing or swaying to the beat: Discrete auditory rhythms entrain stance and promote postural coordination stability

Humans seem to take social and behavioral advantages of entraining themselves with discrete auditory rhythms (e.g., dancing, communicating). We investigated the benefits of such an entrainment on posture during standing (spontaneous entrainment) and during a whole-body swaying task (intentional synchronization). We first evaluated how body sway was entrained by different auditory metronome frequencies (0.25, 0.5, and 1.0Hz). We then assessed the stabilizing role of auditory rhythms on postural control, characterized in a dynamical systems perspective by informational anchoring of the head (local stabilization) and fewer transitions from in-phase to anti-phase ankle-hip coordination (global stabilization). Our results revealed in both situations an entrainment of postural movements by external rhythms. This entrainment tended to be more effective when the metronome frequency (0.25Hz) was close to the dominant sway frequency. Particularly, we found during intentional synchronization that head movements were less variable when paced by a slower beat (informational anchoring), and that phase transitions between the two stable patterns in postural dynamics were delayed. Our findings demonstrate that human bipedal posture can be actively or spontaneously modulated by an external discrete auditory rhythm, which might be exploited for the purpose of learning and rehabilitation.