Charles Lenay

Minimalist approach to perceptual interactions.

Work aimed at studying social cognition in an interactionist perspective often encounters substantial theoretical and methodological difficulties: identifying the significant behavioral variables; recording them without disturbing the interaction; and distinguishing between: (a) the necessary and sufficient contributions of each individual partner for a collective dynamics to emerge; (b) features which derive from this collective dynamics and escape from the control of the individual partners; and (c) the phenomena arising from this collective dynamics which are subsequently appropriated and used by the partners. We propose a minimalist experimental paradigm as a basis for this conceptual discussion: by reducing the sensory inputs to a strict minimum, we force a spatial and temporal deployment of the perceptual activities, which makes it possible to obtain a complete recording and control of the dynamics of interaction. After presenting the principles of this minimalist approach to perception, we describe a series of experiments on two major questions in social cognition: recognizing the presence of another intentional subject; and phenomena of imitation. In both cases, we propose explanatory schema which render an interactionist approach to social cognition clear and explicit. Starting from our earlier work on perceptual crossing we present a new experiment on the mechanisms of reciprocal recognition of the perceptual intentionality of the other subject: the emergent collective dynamics of the perceptual crossing can be appropriated by each subject. We then present an experimental study of opaque imitation (when the subjects cannot see what they themselves are doing). This study makes it possible to characterize what a properly interactionist approach to imitation might be. In conclusion, we draw on these results, to show how an interactionist approach can contribute to a fully social approach to social cognition.

Imitation by social interaction? Analysis of a minimal agent-based model of the correspondence problem

One of the major challenges faced by explanations of imitation is the “correspondence problem”: how is an agent able to match its bodily expression to the observed bodily expression of another agent, especially when there is no possibility of external self-observation? Current theories only consider the possibility of an innate or acquired matching mechanism belonging to an isolated individual. In this paper we evaluate an alternative that situates the explanation of imitation in the inter-individual dynamics of the interaction process itself. We implemented a minimal model of two interacting agents based on a recent psychological study of imitative behavior during minimalist perceptual crossing. The agents cannot sense the configuration of their own body, and do not have access to others body configuration, either. And yet surprisingly they are still capable of converging on matching bodily configurations. Analysis revealed that the agents solved this version of the correspondence problem in terms of collective properties of the interaction process. Contrary to the assumption that such properties merely serve as external input or scaffolding for individual mechanisms, it was found that the behavioral dynamics were distributed across the model as a whole.

Integrating tactile and force feedback for highly dynamic tasks: Technological, experimental and epistemological aspects

For hand-object interaction in real situations the interplay between the local tactile interaction and force interaction seems to be very important. In current haptic interfaces, however, two different trends are present: force feedback devices which offer a permanent invariable grip and a resultant force, and tactile devices, which offer variable local patterns, often used for texture rendering. The purpose of the present work is to combine the two types of devices in a coherent manner. In the new device presented here, the tactile stimulation is obtained from strictly the same interaction loop, and obeys to the same physical model, as the force feedback, providing the information on the spatial distribution of forces circulating between the object and the fingertip. An experiment on following sharp edges of virtual object comparing the force feedback alone and different tactile augmentations is presented and discussed, alone with some open epistemological issues.

Perceptive supplementation for an access to graphical interfaces

Studies using the sensory substitution devices reveal that perceptive activity itself is embodied in a living body capable of movement and possessing its own spatial dimensions. To study the conditions of a prosthetic perception, we developed a minimal device, Tactos, which carries out a coupling between the pen of a graphics tablet and tactile sensory stimulators. This system allows subjects to explore virtual tactile pictures and is intended to give to blind people an access to computer graphics. We will present here experimental results regarding the different aspects of perception using this device.

Designing interactive content with blind users for a perceptual supplementation system

With the spread of ICT and the Internet during the last two decades, more and more tools rely on graphical interfaces that make them scarcely accessible to the visually impaired. The ITOIP project aims at developing the use of a tactile perceptual supplementation system called Tactos. A partnership with a visually impaired persons (VIP) association allows us to conduct a participatory design approach intended to gather first community of users around our system. This article reports on the design approach we have implemented in order to develop usable and useful applications for VIP users. Through a rapid prototyping process we address the development of the use of our technology with blind users representatives. We present the interaction and use principles highlighted from the design of three Tactos applications: a tutorial, a street maps exploration system and a country level map application.

Interpersonal recognition through mediated tactile interaction

For several years, we have been developing a system of perceptual supplementation (Tactos) so as to render spatialized digital information accessible to users with visual deficiencies. After having validated this device in experimental situations and in practical use, we now propose to connect several Tactos systems in a network, so as to allow for access to shared digital spaces via the tactile modality (Intertact). This opening up of previously individual use to collective use makes it possible to conceive digital spaces designed for tactile interaction, by proposing practical, pedagogical and gaming functionalities. This new possibility of tactile interaction opens the way to the production of a technical aid for visually impaired persons with a social dimension. At the same time, the design of shared tactile spaces goes together with a fundamental reflection concerning perceptual interactions. We therefore propose an experimental study in order to provide the necessary steps to characterize the processes of mutual engagement in the interactions. The first results suggest that these processes seem to constitute a mutual dynamics, which is the basis for an active co-construction of meaning.

Acuité perceptive via une interface pseudo-haptique

The goal of this study is to apprehend the perceptive training capacities of a human subject via an artificial device and to also underline their limits and constraints. The principal constraint considered here, is the acuity in other words, the spatial proprieties ratio of the sensor and the explored objects. The experimental device couples the pen of a graphics tablet with tactile sensory stimula-tors. A matrix of virtual receptor field linked to a stylus by means of an equipped computer is responsible for the stimulator activation. The results show: i) that the sub-jects are able to perceive forms via this artificial device and that this perception is forced by the spatial resolution of the sensor, ii) That the subjects are able to adapt their movements to perceive very small forms (0,5 mm height), iii) To develop new exploration strategies.

Perceptual Strategies Under Constrained Movements on a Zoomable Haptic Mobile Device

This study shows that zooming and pointing strategies are influenced by visual constraints when using a haptic mobile device. Participants were required to point on invisible targets that were only detectable via a tactile feedback. Movements were either constrained or unconstrained. Results revealed that pointing and zooming strategies depended on the order of training. Participants who started their training with unconstrained movements, kept using the same strategies even when constraints have been removed. This suggests that constrained movements allowed participants to explore other strategies that would have not been available and extended their repertoire of exploratory strategies related to the haptic zoom.

Joint Perception of a Shared Object: A Minimalist Perceptual Crossing Experiment

The minimalist perceptual crossing paradigm has emphasized the essential role of interpersonal dynamics on social understanding. Within the particular case of minimalist interaction, it has been argued that interpersonal processes can constitute social cognition, at least partially, which calls for a paradigm shift in social cognition studies. In this paper, we review several perceptual crossing experiments and their theoretical implications, and propose an original experiment to go beyond strictly dyadic interactions. Whereas past experiments have used objects as distracters of dyadic interaction, our experiment aims at integrating objects themselves as the goal of interpersonal coordination. We asked 24 subjects to participate in a minimalist perceptual crossing experiment where they had to decide, based on their on-line interaction in a one-dimensional digital space, which of the objects they perceived was also perceptible by their partner. The main results suggest that the mutual awareness of a shared object (SO) arises from the quality of sensorimotor coordination between the partners. Indeed, the presence of a SO acts as a simultaneous affordance that attracts and structures individual perceptive activities, giving both partners the opportunity to co-construct a shared world where their respective actions make sense. We discuss our results by way of an enactive account of social cognition, taking the joint perception of a SO as a first step to account for joint attention.

[D87] Remote tactile interaction

The interface and the software presented use piezoelectric cells to distribute tactile information. The movements of the finger on the screen of a smartphone control 16 tactile stimulators that are located, either on the back of this smartphone, or on the back of the smartphone of the partner. This new device allows at the same time (1) to give to blind people an access to graphic information on the screens (software TACTOS), and (2) to allow tactile interactions with remote partners (software INTERTACT).: http://www.intertact.net/. This device opens the possibility of a mobile access to a tactile Internet, for which we developed some applications: games like “Memory”, teaching spaces, practical information like maps of bus lines; emotional communication (tacticones).