The Projective Consciousness Model: Projective Geometry at the Core of Consciousness and the Integration of Perception, Imagination, Motivation, Emotion, Social Cognition and Action.

Consciousness has been described as acting as a global workspace that integrates perception, imagination, emotion and action programming for adaptive decision making. The mechanisms of this workspace and their relationships to the phenomenology of consciousness need to be further specified. Much research in this area has focused on the neural correlates of consciousness, but, arguably, computational modeling can better be used toward this aim. According to the Projective Consciousness Model (PCM), consciousness is structured as a viewpoint-organized, internal space, relying on 3D projective geometry and governed by the action of the Projective Group as part of a process of active inference. The geometry induces a group-structured subjective perspective on an encoded world model, enabling adaptive perspective taking in agents. Here, we review and discuss the PCM. We emphasize the role of projective mechanisms in perception and the appraisal of affective and epistemic values as tied to the motivation of action, under an optimization process of Free Energy minimization, or more generally stochastic optimal control. We discuss how these mechanisms enable us to model and simulate group-structured drives in the context of social cognition and to understand the mechanisms underpinning empathy, emotion expression and regulation, and approach-avoidance behaviors. We review previous results, drawing on applications in robotics and virtual humans. We briefly discuss future axes of research relating to applications of the model to simulation- and model-based behavioral science, geometrically structured artificial neural networks, the relevance of the approach for explainable AI and human-machine interactions, and the study of the neural correlates of consciousness.

Accounting for endogenous effects in decision-making with a non-linear diffusion decision model.

The Drift-Diffusion Model (DDM) is widely accepted for two-alternative forced-choice decision paradigms thanks to its simple formalism and close fit to behavioral and neurophysiological data. However, this formalism presents strong limitations in capturing inter-trial dynamics at the single-trial level and endogenous influences. We propose a novel model, the non-linear Drift-Diffusion Model (nl-DDM), that addresses these issues by allowing the existence of several trajectories to the decision boundary. We show that the non-linear model performs better than the drift-diffusion model for an equivalent complexity. To give better intuition on the meaning of nl-DDM parameters, we compare the DDM and the nl-DDM through correlation analysis. This paper provides evidence of the functioning of our model as an extension of the DDM. Moreover, we show that the nl-DDM captures time effects better than the DDM. Our model paves the way toward more accurately analyzing across-trial variability for perceptual decisions and accounts for peri-stimulus influences.

Evidence for an internal model of friction when controlling kinetic energy at impact to slide an object along a surface toward a target.

Although the role of an internal model of gravity for the predictive control of the upper limbs is quite well established, evidence is lacking regarding an internal model of friction. In this study, 33 male and female human participants performed a striking movement (with the index finger) to slide a plastic cube-like object to a given target distance. The surface material (aluminum or balsa wood) on which the object slides, the surface slope (-10°, 0, or +10°) and the target distance (25 cm or 50 cm) varied across conditions, with ten successive trials in each condition. Analysis of the object speed at impact and spatial error suggests that: 1) the participants chose to impart a similar speed to the object in the first trial regardless of the surface material to facilitate the estimation of the coefficient of friction; 2) the movement is parameterized across repetitions to reduce spatial error; 3) an internal model of friction can be generalized when the slope changes. Biomechanical analysis showed interindividual variability in the recruitment of the upper limb segments and in the adjustment of finger speed at impact in order to transmit the kinetic energy required to slide the object to the target distance. In short, we provide evidence that the brain builds an internal model of friction that makes it possible to parametrically control a striking movement in order to regulate the amount of kinetic energy required to impart the appropriate initial speed to the object.

Tom Pouce III, an Electronic White Cane for Blind People: Ability to Detect Obstacles and Mobility Performances.

We present a protocol for evaluating the efficiency of an electronic white cane for improving the mobility of blind people. The electronic cane used during the test is the Tom Pouce III, made of LIDAR sensors (light detection and ranging) with tactile feedback. The protocol comprises two parts. The first part, the "detection test", evaluates the efficiency of the sensors in the Tom Pouce III for detecting the obstacles found in everyday life (thin and large poles, apertures) under different environmental conditions (darkness, sun light, rain). The second part of the test, the "mobility test", compares the ability of blind participants to cross a 25 m path by avoiding obstacles with the simple white cane and the electronic cane. The 12 blind participants had between 2 and 20 years of experience of everyday usage of Tom Pouce devices. The results show a significant improvement in the capacity to avoid obstacles with the electronic cane relative to the simple white cane, and there was no speed difference. There was no correlation between the results and the years of experience of the users.

Brain Processes While Struggling With Evidence Accumulation During Facial Emotion Recognition: An ERP Study.

The human brain is tuned to recognize emotional facial expressions in faces having a natural upright orientation. The relative contributions of featural, configural, and holistic processing to decision-making are as yet poorly understood. This study used a diffusion decision model (DDM) of decision-making to investigate the contribution of early face-sensitive processes to emotion recognition from physiognomic features (the eyes, nose, and mouth) by determining how experimental conditions tapping those processes affect early face-sensitive neuroelectric reflections (P100, N170, and P250) of processes determining evidence accumulation at the behavioral level. We first examined the effects of both stimulus orientation (upright vs. inverted) and stimulus type (photographs vs. sketches) on behavior and neuroelectric components (amplitude and latency). Then, we explored the sources of variance common to the experimental effects on event-related potentials (ERPs) and the DDM parameters. Several results suggest that the N170 indicates core visual processing for emotion recognition decision-making: (a) the additive effect of stimulus inversion and impoverishment on N170 latency; and (b) multivariate analysis suggesting that N170 neuroelectric activity must be increased to counteract the detrimental effects of face inversion on drift rate and of stimulus impoverishment on the stimulus encoding component of non-decision times. Overall, our results show that emotion recognition is still possible even with degraded stimulation, but at a neurocognitive cost, reflecting the extent to which our brain struggles to accumulate sensory evidence of a given emotion. Accordingly, we theorize that: (a) the P100 neural generator would provide a holistic frame of reference to the face percept through categorical encoding; (b) the N170 neural generator would maintain the structural cohesiveness of the subtle configural variations in facial expressions across our experimental manipulations through coordinate encoding of the facial features; and (c) building on the previous configural processing, the neurons generating the P250 would be responsible for a normalization process adapting to the facial features to match the stimulus to internal representations of emotional expressions.

Assessing validity evidence for a serious game dedicated to patient clinical deterioration and communication.

BACKGROUND: A serious game (SG) is a useful tool for nurse training. The objectives of this study were to assess validity evidence of a new SG designed to improve nurses' ability to detect patient clinical deterioration. METHODS: The SG (LabForGames Warning) was developed through interaction between clinical and pedagogical experts and one developer. For the game study, consenting nurses were divided into three groups: nursing students (pre-graduate) (group S), recently graduated nurses (graduated < 2 years before the study) (group R) and expert nurses (graduated > 4 years before the study and working in an ICU) (group E). Each volunteer played three cases of the game (haemorrhage, brain trauma and obstructed intestinal tract). The validity evidence was assessed following Messick's framework: content, response process (questionnaire, observational analysis), internal structure, relations to other variables (by scoring each case and measuring playing time) and consequences (a posteriori analysis). RESULTS: The content validity was supported by the game design produced by clinical, pedagogical and interprofessional experts in accordance with the French nurse training curriculum, literature review and pilot testing. Seventy-one nurses participated in the study: S (n = 25), R (n = 25) and E (n = 21). The content validity in all three cases was highly valued by group E. The response process evidence was supported by good security control. There was no significant difference in the three groups' high rating of the game's realism, satisfaction and educational value. All participants stated that their knowledge of the different steps of the clinical reasoning process had improved. Regarding the internal structure, the factor analysis showed a common source of variance between the steps of the clinical reasoning process and communication or the situational awareness errors made predominantly by students. No statistical difference was observed between groups regarding scores and playing time. A posteriori analysis of the results of final examinations assessing study-related topics found no significant difference between group S participants and students who did not participate in the study. CONCLUSION: While it appears that this SG cannot be used for summative assessment (score validity undemonstrated), it is positively valued as an educational tool. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03092440.

Comparative value of a simulation by gaming and a traditional teaching method to improve clinical reasoning skills necessary to detect patient deterioration: a randomized study in nursing students.

BACKGROUND: Early detection and response to patient deterioration influence patient prognosis. Nursing education is therefore essential. The objective of this randomized controlled trial was to compare the respective educational value of simulation by gaming (SG) and a traditional teaching (TT) method to improve clinical reasoning (CR) skills necessary to detect patient deterioration. METHODS: In a prospective multicenter study, and after consent, 2nd year nursing students were randomized into two groups: Simulation by gaming "SG": the student played individually with a serious game consisting of 2 cases followed by a common debriefing with an instructor;Traditional Teaching "TT": the student worked on the same cases in text paper format followed by a traditional teaching course with a PowerPoint presentation by an instructor. CR skill was measured by script concordance tests (80 SCTs, score 0-100) immediately after the session (primary outcome) and on month later. Other outcomes included students' satisfaction, motivation and professional impact. RESULTS: One hundred forty-six students were randomized. Immediately after training, the SCTs scores were 59 ± 9 in SG group (n = 73) and 58 ± 8 in TT group (n = 73) (p = 0.43). One month later, the SCTs scores were 59 ± 10 in SG group (n = 65) and 58 ± 8 in TT group (n = 54) (p = 0.77). Global satisfaction and motivation were highly valued in both groups although significantly greater in the SG group (p < 0.05). The students declared that the training course would have a positive professional impact, with no difference between groups. CONCLUSIONS: In this study assessing nursing student CR to detect patient deterioration, no significant educational difference (SCT), neither immediate nor 1 month later, was observed between training by SG and the TT course. However, satisfaction and motivation were found to be greater with the use of SG. TRIAL REGISTRATION: ClinicalTrials.gov; NCT03428269. Registered 30 january 2018.

Unravelling functional neurology: does spinal manipulation have an effect on the brain? - a systematic literature review.

Background: A recent hypothesis purports that spinal manipulation may cause changes at a brain level. Functional Neurology, a mainly chiropractic approach, promotes the use of spinal manipulation to improve 'brain function' as if it were a proven construct. No systematic review has been performed to investigate how well founded this hypothesis is. Objective: To investigate whether spinal manipulation has an effect on 'brain function' that is associated with any clinical benefits. Method: In this systematic review, the literature was searched in PubMed, Embase, and PEDro (final search February 2018). We included randomized or non-randomized controlled studies, in which spinal manipulation was performed to any region of the spine, applied on either symptomatic or asymptomatic humans, and compared to a sham or to another type of control. The outcome measures had to be stated as direct or proxy markers of 'brain function'. Articles were reviewed blindly by at least two reviewers, using a quality checklist designed for the specific needs of the review. Studies were classified as of 'acceptable', 'medium', or 'low' methodological quality. Results were reported in relation to (i) control intervention (sham, 'inactive control', or 'another physical stimulus') and (ii) study subjects (healthy, symptomatic, or with spinal pain" subjects/spinal pain"), taking into account the quality. Only results obtained from between-group or between-intervention comparisons were considered in the final analysis. Results: Eighteen of 1514 articles were included. Studies were generally of 'low' or 'medium' methodological quality, most comparing spinal manipulation to a control other than a sham. Thirteen out of the 18 studies could be included in the final analysis. Transitory effects of different types of 'brain function' were reported in the three studies comparing spinal manipulation to sham (but of uncertain credibility), in "subclinical neck/spinal pain" subjects or in symptomatic subjects. None of these three studies, of 'medium' or 'acceptable' quality, investigated whether the neurophysiological effects reported were associated with clinical benefits. The remaining 10 studies, generally of 'low' or 'medium' quality, compared spinal manipulation to 'inactive control' or 'another physical stimulus' and similarly reported significant between-group differences but inconsistently. Conclusion: The available evidence suggests that changes occur in 'brain function' in response to spinal manipulation but are inconsistent across and - sometimes - within studies. The clinical relevance of these changes is unknown. It is therefore premature to promote the use of spinal manipulation as a treatment to improve 'brain function'.

Introduction: Une hypothèse récente propose que la manipulation vertébrale causerait des changements neurophysiologiques au niveau du cerveau. En Neurologie Fonctionnelle, approche principalement présente en chiropraxie, l'utilisation de la manipulation vertébrale est déjà promue comme capable d'améliorer le fonctionnement du cerveau. A ce jour, aucune revue systématique de la littérature n'a été conduite afin de connaître l'étendue et la qualité de l'évidence scientifique susceptible de justifier cet usage de la manipulation vertébrale. Objectif: Déterminer, à travers une revue systématique et critique de la littérature, si la manipulation vertébrale a un effet (spécifique) sur le cerveau et, si oui, si celui-ci est associé à un effet clinique. Méthode: Le moteur de recherche PubMed et deux bases de données, Embase et PEDro, ont fait l'objet d'une recherche bibliographique (actualisée en février 2018). Les critères d'inclusion étaient: essais contrôlés, randomisés ou non, dans lesquels la manipulation vertébrale avait été comparée à un placébo ou à un autre type de contrôle, chez des sujets symptomatiques ou asymptomatiques. La manipulation vertébrale pouvait avoir été effectuée au niveau de n'importe quelle région de la colonne vertébrale et les critères de jugement utilisés devaient être indiqués comme capables de mesurer, directement ou indirectement, une forme 'd'activité cérébrale'. La qualité méthodologique des études a été évaluée de manière indépendante par au moins deux chercheurs à l'aide d'une grille de qualité créée pour les besoins de cette revue. Les études ont été classifiées comme étant de qualité méthodologique 'acceptable', 'moyenne', ou 'faible'. Les résultats ont été rapportés de façon narrative, en fonction du type de contrôle utilisé (placébo, 'inactif', ou 'autre stimulus physique') et du type de sujets d'étude (sans problème de santé, symptomatiques, ou présentant des « douleurs rachidiennes subcliniques ¼), en tenant compte de la qualité méthodologique. Seuls les résultats issus de comparaisons inter-groupes ont été pris en compte dans notre analyse finale. Résultats: Dix-huit articles parmi les 1514 titres obtenus ont été inclus. Les études étaient pour la plupart de qualité méthodologique 'faible' ou 'moyenne' et avaient principalement comparé la manipulation vertébrale à une intervention autre que placébo. Les résultats rapportés dans 13 des 18 articles inclus ont finalement été pris en compte. Un effet transitoire sur différentes formes 'd'activité cérébrale' a été rapporté à l'issue de trois études dans lesquelles la manipulation vertébrale avait été comparée à un placébo (de crédibilité cependant incertaine), chez des sujets présentant des « douleurs rachidiennes subcliniques ¼ (n = 2) ou souffrant de cervicalgies non spécifiques aiguës / subaiguës (n = 1). Une potentielle association avec un effet clinique n'a pas été étudiée dans ces trois études, de qualité méthodologique 'moyenne' (n = 2) ou 'acceptable' (n = 1). Dans les 10 études restantes, la plupart de qualité méthodologique 'faible' ou 'moyenne', la manipulation vertébrale avait été comparée à un contrôle 'inactif' ou à un 'autre stimulus physique'. Des différences inter-groupes y ont également été rapportées, parfois de façon inconsistante. Conclusion: La littérature scientifique suggère que des changements neurophysiologiques surviennent au niveau du cerveau en réponse à la manipulation vertébrale mais, de façon inconsistante. La pertinence clinique de ces changements n'est pas connue. Ainsi, il est prématuré d'attribuer à la manipulation vertébrale des bénéfices cliniques via un effet sur le cerveau.

Clinical experience changes the combination and the weighting of audio-visual sources of information.

OBJECTIVE: Although audio and visual information constitute relevant channels to communicate pain, it remains unclear to what extent observers combine and weight these sources of information when estimating others' pain. The present study aimed to examine this issue through the theoretical framework of the Information Integration Theory. The combination and weighting processes were addressed in view of familiarity with others' pain. METHOD: Twenty-six participants familiar with pain (novice podiatry clinicians) and thirty non-specialists were asked to estimate the level of pain associated with different displayed locomotor behaviors. Audio and visual information (i.e., sound and gait kinematics) were combined across different intensities and implemented in animated human stick figures performing a walking task (from normal to pathological gaits). RESULTS: The novice clinicians and non-specialists relied significantly on gaits and sounds to estimate others' pain intensity. The combination of the two types of information obeyed an averaging rule for the majority of the novice clinicians and an additive rule for the non-specialists. The novice clinicians leaned more on gaits in the absence of limping, whereas they depended more on sounds in the presence of limping. The non-specialists relied more on gaits than on sounds. Overall, the novice clinicians attributed greater pain levels than the non-specialists did. CONCLUSION: Depending on a person's clinical experience, the combination of audio and visual pain-related behavior can qualitatively change the processes related to the assessment of others' pain. Non-verbal pain-related behaviors as well as the clinical implications are discussed in view of the assessment of others' pain.

Modeling Emotional Valence Integration From Voice and Touch.

In the context of designing multimodal social interactions for Human-Computer Interaction and for Computer-Mediated Communication, we conducted an experimental study to investigate how participants combine voice expressions with tactile stimulation to evaluate emotional valence (EV). In this study, audio and tactile stimuli were presented separately, and then presented together. Audio stimuli comprised positive and negative voice expressions, and tactile stimuli consisted of different levels of air jet tactile stimulation performed on the arm of the participants. Participants were asked to evaluate communicated EV on a continuous scale. Information Integration Theory was used to model multimodal valence perception process. Analyses showed that participants generally integrated both sources of information to evaluate EV. The main integration rule was averaging rule. The predominance of a modality over the other modality was specific to each individual.

The neuroelectric dynamics of the emotional anticipation of other people's pain.

When we observe a dynamic emotional facial expression, we usually automatically anticipate how that expression will develop. Our objective was to study a neurocognitive biomarker of this anticipatory process for facial pain expressions, operationalized as a mismatch effect. For this purpose, we studied the behavioral and neuroelectric (Event-Related Potential, ERP) correlates, of a match or mismatch, between the intensity of an expression of pain anticipated by the participant, and the intensity of a static test expression of pain displayed with the use of a representational momentum paradigm. Here, the paradigm consisted in displaying a dynamic facial pain expression which suddenly disappeared, and participants had to memorize the final intensity of the dynamic expression. We compared ERPs in response to congruent (intensity the same as the one memorized) and incongruent (intensity different from the one memorized) static expression intensities displayed after the dynamic expression. This paradigm allowed us to determine the amplitude and direction of this intensity anticipation by measuring the observer's memory bias. Results behaviorally showed that the anticipation was backward (negative memory bias) for high intensity expressions of pain (participants expected a return to a neutral state) and more forward (memory bias less negative, or even positive) for less intense expressions (participants expected increased intensity). Detecting mismatch (incongruent intensity) led to faster responses than detecting match (congruent intensity). The neuroelectric correlates of this mismatch effect in response to the testing of expression intensity ranged from P100 to LPP (Late Positive Potential). Path analysis and source localization suggested that the medial frontal gyrus was instrumental in mediating the mismatch effect through top-down influence on both the occipital and temporal regions. Moreover, having the facility to detect incongruent expressions, by anticipating emotional state, could be useful for prosocial behavior and the detection of trustworthiness.

Representational momentum in dynamic facial expressions is modulated by the level of expressed pain: Amplitude and direction effects.

Humans have developed a specific capacity to rapidly perceive and anticipate other people's facial expressions so as to get an immediate impression of their emotional state of mind. We carried out two experiments to examine the perceptual and memory dynamics of facial expressions of pain. In the first experiment, we investigated how people estimate other people's levels of pain based on the perception of various dynamic facial expressions; these differ both in terms of the amount and intensity of activated action units. A second experiment used a representational momentum (RM) paradigm to study the emotional anticipation (memory bias) elicited by the same facial expressions of pain studied in Experiment 1. Our results highlighted the relationship between the level of perceived pain (in Experiment 1) and the direction and magnitude of memory bias (in Experiment 2): When perceived pain increases, the memory bias tends to be reduced (if positive) and ultimately becomes negative. Dynamic facial expressions of pain may reenact an "immediate perceptual history" in the perceiver before leading to an emotional anticipation of the agent's upcoming state. Thus, a subtle facial expression of pain (i.e., a low contraction around the eyes) that leads to a significant positive anticipation can be considered an adaptive process-one through which we can swiftly and involuntarily detect other people's pain.

Neural Correlates of a Perspective-taking Task Using in a Realistic Three-dimmensional Environment Based Task: A Pilot Functional Magnetic Resonance Imaging Study.

OBJECTIVE: Perspective-taking ability is an essential spatial faculty that is of much interest in both health and neuropsychiatric disorders. There is limited data on the neural correlates of perspective taking in the context of a realistic three-dimensional environment. We report the results of a pilot study exploring the same in eight healthy volunteers. METHODS: Subjects underwent two runs of an experiment in a 3 Tesla magnetic resonance imaging (MRI) involving alternate blocks of a first-person perspective based allocentric object location memory task (OLMT), a third-person perspective based egocentric visual perspective taking task (VPRT), and a table task (TT) that served as a control. Difference in blood oxygen level dependant response during task performance was analyzed using Statistical Parametric Mapping software, version 12. Activations were considered significant if they survived family-wise error correction at the cluster level using a height threshold of p＜0.001, uncorrected at the voxel level. RESULTS: A significant difference in accuracy and reaction time based on task type was found. Subjects had significantly lower accuracy in VPRT compared to TT. Accuracy in the two active tasks was not significantly different. Subjects took significantly longer in the VPRT in comparison to TT. Reaction time in the two active tasks was not significantly different. Functional MRI revealed significantly higher activation in the bilateral visual cortex and left temporoparietal junction (TPJ) in VPRT compared to OLMT. CONCLUSION: The results underscore the importance of TPJ in egocentric manipulation in healthy controls in the context of reality-based spatial tasks.

A model-driven approach to studying dissociations between body size mental representations in anorexia nervosa.

This study compared dissociations between mental representations of current, ideal and normal body sizes (i.e., Current BS, Ideal BS and Normal BS) for women with anorexia nervosa (AN group, n=56) and healthy women (control group, n=56). Along the lines of the single channel model of Cornelissen et al. (2013), the discrepancy between Current BS and BMI for both groups was adequately described along a common linear continuum of Current BS (mis)perception. Body size mental representations were ranked similarly (Ideal BS

Patients with schizophrenia are less prone to interpret virtual others' empathetic questioning as helpful.

Individuals with schizophrenia are impaired in their neurocognition and present cognitive biases. These impairments may lead to a deficit in recognizing helping intentions of others. To investigate recognition of help, we designed a card-guessing game (Virtual Help Recognition Paradigm) involving two successive virtual agents asking questions to the participant at different moments of the game. These questions were either empathetic (i.e. on the subject's feelings) or non-empathetic (i.e. on technical aspects of the game). We assessed how much the participant felt that the virtual agent had helped him and, her attitude and personality traits. We measured how much the participant trusted the virtual agent with a monetary allocation procedure. Twenty individuals with schizophrenia and twenty healthy controls were recruited. The controls' ratings demonstrated that they interpreted empathetic questioning as helping and rewarded it positively with an increased monetary allocation. Participants with schizophrenia had a reduced perception of the differences between the two agents. Only the rating concerning the "interest/attention" of the agent toward these participants yielded significant differences among conditions. Hypothetically, individuals with schizophrenia take into account the fact they are the object of another's attention, but may fail to infer a helping intention and to behave accordingly.

Neuroelectric Correlates of Pragmatic Emotional Incongruence Processing: Empathy Matters.

The emotions people feel can be simulated internally based on emotional situational contexts. In the present study, we assessed the behavioral and neuroelectric effects of seeing an unexpected emotional facial expression. We investigated the correct answer rate, response times and Event-Related Potential (ERP) effects during an incongruence paradigm between emotional faces and sentential contexts allowing emotional inferences. Most of the 36 healthy participants were recruited from a larger population (1 463 subjects), based on their scores on the Empathy Questionnaire (EQ). Regression analyses were conducted on these ratings using EQ factors as predictors (cognitive empathy, emotional reactivity and social skills). Recognition of pragmatic emotional incongruence was less accurate (P < .05) and slower (P < .05) than recognition of congruence. The incongruence effect on response times was inversely predicted by social skills. A significant N400 incongruence effect was found at the centro-parietal (P < .001) and centro-posterior midline (P < .01) electrodes. Cognitive empathy predicted the incongruence effect in the left occipital region, in the N400 time window. Finally, incongruence effects were also found on the LPP wave, in frontal midline and dorso-frontal regions, (P < .05), with no modulation by empathy. Processing pragmatic emotional incongruence is more cognitively demanding than congruence (as reflected by both behavioral and ERP data). This processing shows modulation by personality factors at the behavioral (through self-reported social skills) and neuroelectric levels (through self-reported cognitive empathy).

The embodied dynamics of perceptual causality: a slippery slope?

In Michotte's launching displays, while the launcher (object A) seems to move autonomously, the target (object B) seems to be displaced passively. However, the impression of A actively launching B does not persist beyond a certain distance identified as the "radius of action" of A over B. If the target keeps moving beyond the radius of action, it loses its passivity and seems to move autonomously. Here, we manipulated implied friction by drawing (or not) a surface upon which A and B are traveling, and by varying the inclination of this surface in screen- and earth-centered reference frames. Among 72 participants (n = 52 in Experiment 1; n = 20 in Experiment 2), we show that both physical embodiment of the event (looking straight ahead at a screen displaying the event on a vertical plane vs. looking downwards at the event displayed on a horizontal plane) and contextual information (objects moving along a depicted surface or in isolation) affect interpretation of the event and modulate the radius of action of the launcher. Using classical mechanics equations, we show that representational consistency of friction from radius of action responses emphasizes the embodied nature of frictional force in our cognitive architecture.

How and why affective and reactive virtual agents will bring new insights on social cognitive disorders in schizophrenia? An illustration with a virtual card game paradigm.

In recent decades, many studies have shown that schizophrenia is associated with severe social cognitive impairments affecting key components, such as the recognition of emotions, theory of mind, attributional style, and metacognition. Most studies investigated each construct separately, precluding analysis of the interactive and immersive nature of real-life situation. Specialized batteries of tests are under investigation to assess social cognition, which is thought now as a link between neurocognitive disorders and impaired functioning. However, this link accounts for a limited part of the variance of real-life functioning. To fill this gap, advances in virtual reality and affective computing have made it possible to carry out experimental investigations of naturalistic social cognition, in controlled conditions, with good reproducibility. This approach is illustrated with the description of a new paradigm based on an original virtual card game in which subjects interpret emotional displays from a female virtual agent, and decipher her helping intentions. Independent variables concerning emotional expression in terms of valence and intensity were manipulated. We show how several useful dependant variables, ranging from classic experimental psychology data to metacognition or subjective experiences records, may be extracted from a single experiment. Methodological issues about the immersion into a simulated intersubjective situation are considered. The example of this new flexible experimental setting, with regards to the many constructs recognized in social neurosciences, constitutes a rationale for focusing on this potential intermediate link between standardized tests and real-life functioning, and also for using it as an innovative media for cognitive remediation.

Predicting where a ball will land: from thrower's body language to ball's motion.

To predict where a thrown ball will land, an observer may use visual information about its trajectory. However, in addition, the thrower's body language (i.e., body movement and facial expression) may contain useful information that could be used by the observer to understand intention and emotional state. Here, we investigated how observers estimated a ball's landing point thrown by a virtual agent with different amounts of information from body language. In addition, occlusion time was varied to examine how it potentiates the use of body-language information. Results showed that body movement and facial expression carry information about thrower's effort. However, once the ball has left the thrower's hand, advance information on facial expression does contribute to judgments only if consistent with the amplitude of the throw. Moreover, as the occlusion time increases, a stronger influence of the body movement is observed for estimating the landing point. The overriding effect of ball's trajectory availability over body language is discussed.

Mental rotation and the motor system: embodiment head over heels.

We examined whether body parts attached to abstract stimuli automatically force embodiment in a mental rotation task. In Experiment 1, standard cube combinations reflecting a human pose were added with (1) body parts on anatomically possible locations, (2) body parts on anatomically impossible locations, (3) colored end cubes, and (4) simple end cubes. Participants (N=30) had to decide whether two simultaneously presented stimuli, rotated in the picture plane, were identical or not. They were fastest and made less errors in the possible-body condition, but were slowest and least accurate in the impossible-body condition. A second experiment (N=32) replicated the results and ruled out that the poor performance in the impossible-body condition was due to the specific stimulus material. The findings of both experiments suggest that body parts automatically trigger embodiment, even when it is counterproductive and dramatically impairs performance, as in the impossible-body condition. It can furthermore be concluded that body parts cannot be used flexibly for spatial orientation in mental rotation tasks, compared to colored end cubes. Thus, embodiment appears to be a strong and inflexible mechanism that may, under certain conditions, even impede performance.