Do Object Affordances Modulate the Sense of Embodiment in Virtual Human-Tool Interaction? Reflection for the Interactive Artificial Environment

Object manipulation is essential to build the surrounding reality, and affordances—the action possibilities offered by the environment—have a crucial role in human-tool interaction. Due to the exponential growth of the metaverse, a research question arises: Does the theoretical model behind the human-tool interaction also work in artificial reality? The present study aimed to investigate the difference in the sense of embodiment in human-tool interaction between usual and unusual objects in an immersive 360-degree video. The environment is a recording of a human arm that interacts with various tools while leaning on a table. Forty-four participants took part in the study, and they were randomized into two groups, usual or unusual objects, and in two within-participants conditions, reach to move or reach to use. Results showed no significant difference in the embodiment between usual and unusual objects, demonstrating that the ventral and dorsal streams may perfectly integrate information in the artificial environment as in the real world. Participants felt present in the virtual environment, as demonstrated by the factor location of embodiment, so they believed they could interact with any tools, independently of their affordances. The study contributes to understanding the mechanisms behind human-tool interaction in the artificial environment

An active inference model of hierarchical action understanding, learning and imitation

We advance a novel active inference model of the cognitive processing that underlies the acquisition of a hierarchical action repertoire and its use for observation, understanding and imitation. We illustrate the model in four simulations of a tennis learner who observes a teacher performing tennis shots, forms hierarchical representations of the observed actions, and imitates them. Our simulations show that the agent's oculomotor activity implements an active information sampling strategy that permits inferring the kinematic aspects of the observed movement, which lie at the lowest level of the action hierarchy. In turn, this low-level kinematic inference supports higher-level inferences about deeper aspects of the observed actions: proximal goals and intentions. Finally, the inferred action representations can steer imitative responses, but interfere with the execution of different actions. Our simulations show that hierarchical active inference provides a unified account of action observation, understanding, learning and imitation and helps explain the neurobiological underpinnings of visuomotor cognition, including the multiple routes for action understanding in the dorsal and ventral streams and mirror mechanisms

Il sistema di allenamento analogico/simbolico nello sport della pallavolo: Una valutazione delle componenti mnesitico/attentive

I benefici che l’attività motoria opera sia nell’età adulta che durante l’infanzia sono molteplici. Tra questi, si annoverano i miglioramenti delle abilità percettive, attentive e mnestiche. Lo scopo del presente lavoro è verificare se le capacità mnestiche ed attentive possano essere incrementate dalla messa in opera di un’offerta formativa specifica. Due gruppi di bambini, di età compresa tra i sei e i dieci anni sono stati avviati al gioco della pallavolo. Un gruppo è stato allenato con un metodo che carica di significati i movimenti corporei dell’allenatore e dei compagni al fine di associare tali movimenti allo svolgimento di future indicazioni da eseguire (Pittera, Pedata e Ligas, 2008). L’altro gruppo ha svolto esercizi propedeutici alla pallavolo attraverso la focalizzazione sull’apprendimento dei gesti tecnici. La differenza tra i dati raccolti all’inizio e alla fine del periodo di allenamento preso in esame evidenziarono un miglioramento della capacità di ricordare azioni motorie; nessun miglioramento apparve però per quanto ha riguardato il numero di posizioni spaziali o il numero di componenti verbali da ricordare. Sorprendentemente, poi, nessun miglioramento emerse nelle misure di attenzione sostenuta. I risultati suggeriscono come, focalizzando l’attenzione dei discenti sugli aspetti motori dell’esercizio, e facendo in modo che questi aumentino di significato al fine della successiva realizzazione di nuovi compiti, si possa aumentare una capacità basilare di ogni apprendimento sportivo, ovvero la capacità di ricordare nuove azioni

The positive impact of physical activity on working memory abilities: Evidence from a large Italian pre-adolescent sample

Physical activity (PA) is an essential component of people's well-being. Copious evidence argues for its protective effect across individuals' lifespan. However, its role as a factor of enhancement for human cognitive skills is still a matter of study. The present work aims to provide conclusive evidence about PA's role in modulating working memory skills in active pre-adolescent children. By enrolling a large number of participants, we tested the effect of PA on Digit Span Backwards (DSB), a well-consolidated test taxing primarily short-term auditory memory, i.e., less dependent on attention fluctuations. Higher working memory capacity was assumed to emerge in the participants practising PA compared to the less active ones. Moreover, due to the different activities participants reported to practice, we expected that children practising open-skill activities manifested better memory skills than the peers practising closed-skill activities, due to the intrinsic nature of the two forms of exercises. Data supported the previous hypothesis highlighting PA's positive effect; however, they did not keep the assumed differences for open vs closed skills. Results are discussed in the light of the cognitive efforts required to sport beginners, particularly in the light of what they are prompted to code, remember and recall in each step of the proposed exercises

Body ownership illusion through virtual reality as modulator variable for limbs rehabilitation after stroke: a systematic review

Stroke is the leading cause of motor impairments and generates distortion of body representation. Hence, stroke can modulate the sense of embodiment, namely the feeling of being inside the body (ownership), in the place where the body is located (location), and moving the body according to its own intentions (agency). A growing number of studies have adopted virtual reality (VR) to train motor abilities. However, the impact of the body illusion on the rehabilitation outcome is not fully understood. The present systematic review investigates the modulating role of the body illusion elicited by VR on motor rehabilitation in post-stroke patients after embodying a virtual avatar. The research was led in the main databases—PubMed, Scopus, PsychINFO, and Web of Science—and four studies matched the inclusion criteria (e.g., to have a sample of adult post-stroke patients, to use VR as an instrument for motor rehabilitation, to adopt the paradigm of the body illusion as a modulator for motor rehabilitation, to test the sense of body illusion outcome). Research outcomes demonstrated that two studies adopted the immersive and two the non-immersive embodied VR; three studies focused on the upper limb, and one on lower limb rehabilitation. Two studies compare VR training with traditional therapy, and two are pilot studies with only one experimental group. The studies demonstrated the feasibility of the body illusion as an accelerator for motor rehabilitation compared to the non-embodied condition, and as a positive correlator of the rehabilitation outcome. The finding should be taken with caution due to the limited studies included; however, they are encouraging to justify further research efforts in this area

L'effetto specifico delle discipline sportive nella predizione di un'azione di gioco: uno studio pilota su pallavolisti e calciatori

Nel presente studio sono stati testati tre diversi gruppi di atleti (Pallavolisti di Serie A1, pallavolisti under 16, calciatori under 16) al fine di indagare le loro capacita' di predire il risultato di un'azione di palleggio. Le azioni di palleggio sono state videoriprese durante partite reali di pallavolo di Serie A e somministrate a computer attraverso la tecnica di occlusione temporale. La capacita' predittiva e' risultata essere in funzione dello sport praticato, con migliori risultati da parte degli atleti piu' evoluti. Contrariamente a quanto atteso, non e', pero', emerso un vantaggio per gli atleti che erano usi compiere le stesse azioni mostrate in video (i.e., i palleggiatori). I risultati sono stati discussi alla luce delle informazioni motorie condivise tra chi osserva e chi compie l'azione. English abstract Title: The sport action prediction emerges in function of sport expertise: a pilot study with volleyball players and footballers. In the present study we tested three different groups of athletes (volleyball Serie A1, under-16 volleyball players, soccer players under 16) to investigate their ability to predict the results of volleyball settings performed by a professional setter. The settings were presented in videos recorded during real games played by team of the Major Italian League. They were administered using the technique of temporal occlusion to athletes sat in front of a computer screen. The ability to predict the result of the setting actions emerged to be in function of the practiced sport with expert athletes responding better. Contrary to what expected we did not find higher performance for those athletes who share the more the same motor repertoire with the observed setter. The results are discussed in light of amount of motor information shared between observer and observed

STIMA: a short screening test for ideo-motor apraxia, selective for action meaning and bodily district

We propose STIMA, a short test for ideo-motor apraxia, allowing us to quantify the apraxic deficit according to action meaning and affected body segment. STIMA is based on a neurocognitive model holding that there are two processes involved in action imitation (i.e., a semantic route for recognizing and imitating known gestures, and a direct route for reproducing new gestures). The test allows to identify which imitative process has been selectively impaired by brain damage (direct vs. semantic route) and possible deficits depending on the body segment involved (hand/limb vs. hand/fingers). N = 111 healthy participants were administered with an imitation task in two separated blocks of known and new gestures. In each block, half of the gestures were performed mainly with the proximal part of the upper limb and the remaining half with the distal one. It resulted in 18 known gestures (nine proximal and nine distal) and 18 new gestures (nine proximal and nine distal) for a total of 36. Each gesture was presented up to a maximum of two times. Detailed criteria are used to assign the final imitation score. Cut offs, equivalent scores and main percentile scores were computed for each subscale. Participants imitated better known than new gestures, and proximal better than distal gestures. Age influenced performance on all subscales, while education only affected one subscale. STIMA is easy and quick to administer, and compared to previous tests, it offers important information for planning adequate rehabilitation programs based on the functional locus of the deficit

A Multifunctional Adaptive and Interactive AI system to support people living with stroke, acquired brain or spinal cord injuries: A study protocol

Background: Acquired brain injury and spinal cord injury are leading causes of severe motor disabilities impacting a person's autonomy and social life. Enhancing neurological recovery driven by neurogenesis and neuronal plasticity could represent future solutions; however, at present, recovery of activities employing assistive technologies integrating artificial intelligence is worthy of examining. MAIA (Multifunctional, adaptive, and interactive AI system for Acting in multiple contexts) is a human-centered AI aiming to allow end-users to control assistive devices naturally and efficiently by using continuous bidirectional exchanges among multiple sensorimotor information. Methods: Aimed at exploring the acceptability of MAIA, semi-structured interviews (both individual interviews and focus groups) are used to prompt possible end-users (both patients and caregivers) to express their opinions about expected functionalities, outfits, and the services that MAIA should embed, once developed, to fit end-users needs. Discussion: End-user indications are expected to interest MAIA technical, health-related, and setting components. Moreover, psycho-social issues are expected to align with the technology acceptance model. In particular, they are likely to involve intrinsic motivational and extrinsic social aspects, aspects concerning the usefulness of the MAIA system, and the related ease to use. At last, we expect individual factors to impact MAIA: gender, fragility levels, psychological aspects involved in the mental representation of body image, personal endurance, and tolerance toward AT-related burden might be the aspects end-users rise in evaluating the MAIA project