An open-source perceptual crossing device for investigating brain dynamics during human interaction.

The Perceptual Crossing Device (PCD) introduced in this report is an updated tool designed to facilitate the exploration of brain activity during human interaction with seamless real time integration with EEG equipment. It incorporates haptic and auditory feedback mechanisms, enabling interactions between two users within a virtual environment. Through a unique circular motion interface that enables intuitive virtual interactions, users can experience the presence of their counterpart via tactile or auditory cues. This paper highlights the key characteristics of the PCD, aiming to validate its efficacy in augmenting the understanding of human interactions. Furthermore, by offering an accessible and intuitive interface, the PCD stands to foster greater community engagement in the realm of embodied cognitive science and human interaction studies. Through this device, we anticipate a deeper comprehension of the complex neural dynamics underlying human interaction, thereby contributing a valuable resource to both the scientific community and the broader public.

Ecological and Convergent Validity of Experimentally and Dynamically Assessed Capacity for Social Contingency Detection Using the Perceptual Crossing Experiment in Adolescence.

The Perceptual Crossing Experiment (PCE) captures the capacity for social contingency detection using real-time social interaction dynamics but has not been externally validated. We tested ecological and convergent validity of the PCE in a sample of 208 adolescents from the general population, aged 11 to 19 years. We expected associations between PCE performance and (a) quantity and quality of social interaction in daily life, using Experience Sampling Methodology (ESM; ecological validity) and (b) self-reported social skills using a questionnaire (convergent validity). We also expected PCE performance to better explain variance in ESM social measures than self-reported social skills. Multilevel analyses showed that only self-reported social skills were positively associated with social experience of company in daily life. These initial results do not support ecological and convergent validity of the PCE. However, fueled by novel insights regarding the complexity of capturing social dynamics, we identified promising methodological advances for future validation efforts.

The Feeling Is Mutual: Clarity of Haptics-Mediated Social Perception Is Not Associated With the Recognition of the Other, Only With Recognition of Each Other.

The enactive theory of perception hypothesizes that perceptual access to objects depends on the mastery of sensorimotor contingencies, that is, on the know-how of the regular ways in which changes in sensations depend on changes in movements. This hypothesis can be extended into the social domain: perception of other minds is constituted by mastery of self-other contingencies, that is, by the know-how of the regular ways in which changes in others' movements depend on changes in one's movements. We investigated this proposal using the perceptual crossing paradigm, in which pairs of players are required to locate each other in an invisible one-dimensional virtual space by using a minimal haptic interface. We recorded and analyzed the real-time embodied social interaction of 10 pairs of adult participants. The results reveal a process of implicit perceptual learning: on average, clarity of perceiving the other's presence increased over trials and then stabilized. However, a clearer perception of the other was not associated with correctness of recognition as such, but with both players correctly recognizing each other. Furthermore, the moments of correct mutual recognition tended to happen within seconds. The fact that changes in social experience can only be explained by the successful performance at the level of the dyad, and that this veridical mutual perception tends toward synchronization, lead us to hypothesize that integration of neural activity across both players played a role.

Investigating real-time social interaction in pairs of adolescents with the Perceptual Crossing Experiment.

The study of real-time social interaction provides ecologically valid insight into social behavior. The objective of the current research is to experimentally assess real-time social contingency detection in an adolescent population, using a shortened version of the Perceptual Crossing Experiment (PCE). Pairs of 148 adolescents aged between 12 and 19 were instructed to find each other in a virtual environment interspersed with other objects by interacting with each other using tactile feedback only. Across six rounds, participants demonstrated increasing accuracy in social contingency detection, which was associated with increasing subjective experience of the mutual interaction. Subjective experience was highest in rounds when both participants were simultaneously accurate in detecting each other's presence. The six-round version yielded comparable social contingency detection outcome measures to a ten-round version of the task. The shortened six-round version of the PCE has therefore enabled us to extend the previous findings on social contingency detection in adults to an adolescent population, enabling implementation in prospective research designs to assess the development of social contingency detection over time.

Sensitivity to Social Contingency in Adults with High-Functioning Autism during Computer-Mediated Embodied Interaction.

Autism Spectrum Disorder (ASD) can be understood as a social interaction disorder. This makes the emerging "second-person approach" to social cognition a more promising framework for studying ASD than classical approaches focusing on mindreading capacities in detached, observer-based arrangements. According to the second-person approach, embodied, perceptual, and embedded or interactive capabilities are also required for understanding others, and these are hypothesized to be compromised in ASD. We therefore recorded the dynamics of real-time sensorimotor interaction in pairs of control participants and participants with High-Functioning Autism (HFA), using the minimalistic human-computer interface paradigm known as "perceptual crossing" (PC). We investigated whether HFA is associated with impaired detection of social contingency, i.e., a reduced sensitivity to the other's responsiveness to one's own behavior. Surprisingly, our analysis reveals that, at least under the conditions of this highly simplified, computer-mediated, embodied form of social interaction, people with HFA perform equally well as controls. This finding supports the increasing use of virtual reality interfaces for helping people with ASD to better compensate for their social disabilities. Further dynamical analyses are necessary for a better understanding of the mechanisms that are leading to the somewhat surprising results here obtained.

Multi-Scale Coordination of Distinctive Movement Patterns During Embodied Interaction Between Adults With High-Functioning Autism and Neurotypicals.

Autism Spectrum Disorder (ASD) can be understood as a social interaction disorder. This requires researchers to take a "second-person" stance and to use experimental setups based on bidirectional interactions. The present work offers a quantitative description of movement patterns exhibited during computer-mediated real-time sensorimotor interaction in 10 dyads of adult participants, each consisting of one control individual (CTRL) and one individual with high-functioning autism (HFA). We applied time-series analyses to their movements and found two main results. First, multi-scale coordination between participants was present. Second, despite this dyadic alignment and our previous finding that individuals with HFA can be equally sensitive to the other's presence, individuals' movements differed in style: in contrast to CTRLs, HFA participants appeared less inclined to sustain mutual interaction and instead explored the virtual environment more generally. This finding is consistent with social motivation deficit accounts of ASD, as well as with hypersensitivity-motivated avoidance of overstimulation. Our research demonstrates the utility of time series analyses for the second-person stance and complements previous work focused on non-dynamical and performance-based variables.

Time-Series Analysis of Embodied Interaction: Movement Variability and Complexity Matching As Dyadic Properties.

There is a growing consensus that a fuller understanding of social cognition depends on more systematic studies of real-time social interaction. Such studies require methods that can deal with the complex dynamics taking place at multiple interdependent temporal and spatial scales, spanning sub-personal, personal, and dyadic levels of analysis. We demonstrate the value of adopting an extended multi-scale approach by re-analyzing movement time-series generated in a study of embodied dyadic interaction in a minimal virtual reality environment (a perceptual crossing experiment). Reduced movement variability revealed an interdependence between social awareness and social coordination that cannot be accounted for by either subjective or objective factors alone: it picks out interactions in which subjective and objective conditions are convergent (i.e., elevated coordination is perceived as clearly social, and impaired coordination is perceived as socially ambiguous). This finding is consistent with the claim that interpersonal interaction can be partially constitutive of direct social perception. Clustering statistics (Allan Factor) of salient events revealed fractal scaling. Complexity matching defined as the similarity between these scaling laws was significantly more pronounced in pairs of participants as compared to surrogate dyads. This further highlights the multi-scale and distributed character of social interaction and extends previous complexity matching results from dyadic conversation to non-verbal social interaction dynamics. Trials with successful joint interaction were also associated with an increase in local coordination. Consequently, a local coordination pattern emerges on the background of complex dyadic interactions in the PCE task and makes joint successful performance possible.