Peripersonal Space and Margin of Safety around the Body: Learning Visuo-Tactile Associations in a Humanoid Robot with Artificial Skin

This paper investigates a biologically motivated model of peripersonal space through its implementation on a humanoid robot. Guided by the present understanding of the neurophysiology of the fronto-parietal system, we developed a computational model inspired by the receptive fields of polymodal neurons identified, for example, in brain areas F4 and VIP. The experiments on the iCub humanoid robot show that the peripersonal space representation i) can be learned efficiently and in real-time via a simple interaction with the robot, ii) can lead to the generation of behaviors like avoidance and reaching, and iii) can contribute to the understanding the biological principle of motor equivalence. More specifically, with respect to i) the present model contributes to hypothesizing a learning mechanisms for peripersonal space. In relation to point ii) we show how a relatively simple controller can exploit the learned receptive fields to generate either avoidance or reaching of an incoming stimulus and for iii) we show how the robot can select arbitrary body parts as the controlled end-point of an avoidance or reaching movement

The Peripersonal Space: A Space to INTER-ACT Action- and Social-related Modulations of the Space around Us

The zone surrounding our body is of vital importance. In neuroscience this space is captured by the concept of peripersonal space (PPS), a plastic representation integrating tactile and visual stimuli presented on/close to the body. PPS is thought to contribute to the efficient guidance of actions, yet, a clear demonstration of this function is critically lacking. In the first study we provided strong support to this hypothesis by revealing that visual and tactile stimuli interact already during action planning. Such a PPS remapping that precedes motor execution is ideally suited to guiding actions. Recently, it has been suggested a possible PPS involvement in social interactions. In social psychology, interpersonal space (IPS) is the area individuals maintain around themselves into which others cannot intrude without arousing discomfort. Because of some similarities, some authors raised the question of whether PPS and IPS share some functional features. In the second and third study we tested this hypothesis by taking advantage of PPS remapping induced by tool-use. First, we showed that “standard” tool-use ‘extends’ PPS, as measured by reaching-distance toward a peer, but does not affect IPS, as measured by the comfort-distance toward the same peer. Then, we demonstrated that a novel “social” tool-use ‘extends’ PPS and ‘reduces’ IPS. These findings clearly disconfirm the hypothesis of functional overlap between the two spaces. The last study examines the sensitivity of PPS to a fundamental social dimension: ownership. The results indicate that ownership of an object is critical for the PPS remapping to emerge. Visual stimuli strongly affected touch perception during action only when the object belonged to the participant. A similar remapping emerged when simply observing a peer acting on her own object. Taken together, these findings critically inform current models about space perception and about its function in our sensorimotor and social inter-actions

Haptic Media Scenes

The aim of this thesis is to apply new media phenomenological and enactive embodied cognition approaches to explain the role of haptic sensitivity and communication in personal computer environments for productivity. Prior theory has given little attention to the role of haptic senses in influencing cognitive processes, and do not frame the richness of haptic communication in interaction design—as haptic interactivity in HCI has historically tended to be designed and analyzed from a perspective on communication as transmissions, sending and receiving haptic signals. The haptic sense may not only mediate contact confirmation and affirmation, but also rich semiotic and affective messages—yet this is a strong contrast between this inherent ability of haptic perception, and current day support for such haptic communication interfaces. I therefore ask: How do the haptic senses (touch and proprioception) impact our cognitive faculty when mediated through digital and sensor technologies? How may these insights be employed in interface design to facilitate rich haptic communication? To answer these questions, I use theoretical close readings that embrace two research fields, new media phenomenology and enactive embodied cognition. The theoretical discussion is supported by neuroscientific evidence, and tested empirically through case studies centered on digital art. I use these insights to develop the concept of the haptic figura, an analytical tool to frame the communicative qualities of haptic media. The concept gauges rich machine- mediated haptic interactivity and communication in systems with a material solution supporting active haptic perception, and the mediation of semiotic and affective messages that are understood and felt. As such the concept may function as a design tool for developers, but also for media critics evaluating haptic media. The tool is used to frame a discussion on opportunities and shortcomings of haptic interfaces for productivity, differentiating between media systems for the hand and the full body. The significance of this investigation is demonstrating that haptic communication is an underutilized element in personal computer environments for productivity and providing an analytical framework for a more nuanced understanding of haptic communication as enabling the mediation of a range of semiotic and affective messages, beyond notification and confirmation interactivity

A multimodal investigation of matching mechanisms in automatic imitation

In recent years, research on imitation focused on investigating the underlying neural mechanisms; to this aim simple paradigms were developed to experimentally investigate the phenomenon. Following the natural tendency of humans to mimic gestures and postures of their conspecifics, paradigms of automatic imitation are nowadays widely used in the field. The main aim of my dissertation is to investigate how imitation occurs using an automatic imitation paradigm, in particular focusing on the matching processes that are required to map model and performers actions.The dissertation contains six chapters. In chapter 1, I will provide a brief background of the current theoretical accounts of imitation and of the concepts of automatic imitation and compatibility effects. I will particularly focus on the questions concerning automatic imitation that are still to be fully addressed, particularly those related to the distinction of imitative and spatial compatibility. I will also address the neuroimaging and neuropsychological literature on the neural correlates of imitation. In chapter 2, I will present a neuroimaging study I carried out to investigate the imitation components. Throughout all the studies of this thesis, we used a simple automatic imitation paradigm that is suitable to differentiate between the spatial compatibility and the imitative compatibility, due to the anatomical correspondence between model and performer. Results of the first study showed that the parietal opercula are active anytime the anatomical correspondence between model and performer is present. Hence, in chapter 3 I will present a study in which double-pulse TMS was used to investigate the role of the parietal opercula in automatic imitation, and in particular in coding the imitative compatibility. Results showed that when the activity in the parietal opercula is interfered by TMS, the imitative compatibility effect disappears. In the second part of my thesis I have investigated the factors that can interact with and modulate imitative behaviors. Chapter 4 contains an fMRI study in which the role of the model in imitation is investigated. Using a simplified version of the automatic imitation paradigm, I found that the fronto-parietal network, usually associated to imitation, is more active when participants perform actions that are compatible with those performed by a human model than by a non biological model. Moreover, in this study I have also investigated how different emotional contexts can influence the automatic tendency to imitate. The results showed that the activation of the fronto-parietal network is suppressed by emotional context, such as an angry face, that does not promote affiliative tendencies. In chapter 5 I will describe a neuropsychological study on brain damaged patients. Associations and dissociations between automatic imitation and action imitation were investigated, to analyze the differences between the two types of imitation. Moreover, the role of putative body representations in imitation and whether these body representations are needed for imitation has been investigated. Lastly, in chapter 6 I will wrap up the main results of my dissertation and I will argue that I was able to provide evidence that in automatic imitation an anatomical matching operates between the model and the performer, and that this is sustained by the parietal opercula. In addition I clarified the importance of the model, showing that the activity of fronto-parietal regions supporting imitative behaviors is modulated by model identity

Visual Neuroscience of Robotic Grasping

Supporting Informatio