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Atelier sur la genèse de la perception et de la notion d'espace chez le robot et l'hommeWorkshop on the genesis of perception and the notion of space in machines and humans
jeudi 18 et vendredi 19 octobre 2001 |
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Comité d'organisation : Kevin O'REGAN (LPE, Paris 5) et Jean-Pierre
NADAL (ENS)
avec l'aide administrative d'Aline Bompas (LPE, Paris 5)
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Géométrie et Cognition (Responsable Giuseppe Longo) http://www.di.ens.fr/~longo/geocogni.html groupe de travail du CENECC : CENtre d'Etudes des systèmes Complexes et de la Cognition http://www.cenecc.ens.fr Avec le soutien de l' Action Cognitique du Ministère de la Recherche (Directrice Catherine Fuchs) http://www.education.gouv.fr/recherche/organisa/cognib.htm |
Programme
(Interventions : 40 mn + discussion 10 mn)
jeudi 18 octobre
chairman : JP. Nadal (ENS, Paris)
vendredi 19 octobre
chairman : M. Auvray (LPE, Paris)
"Sensory prostheses to study perceptual learning"
Sylvain Hanneton
Laboratoire Neurophysique et Physiologie du Système Moteur
CNRS FRE 2361
Université René Descartes – UFR Biomédicale
des Saints Pères, 45, rue des Saints Pères – 75270 Paris
CEDEX 06 (sylvain.hanneton@staps.univ-paris5.fr)
Abstract: Sensory prosthesis does not substitute a sense to a deficient
one. They induce new ways to sense and explore the environment trough the
emergence of new sensation/action coupling. This can be achieved only after
a learning period that leads to the forgetting (embodiment ?) of the prosthesis.
We address the question of the use of sensory prostheses as experimental
tools for the study of perceptual learning. We present some preliminary
results and discuss the adequacy of classical models of perceptual processes
to our observations. We finally emphasize the need of new theoretical issues
that could help to account for the behavior of subjects.
"Dispositifs de Substitution Sensorielle visuo-tactiles
et Perception de l’espace: Mesures d’Acuité et Navigation spatiale"
Hervé Segond (1) & Eliana
Sampaio (2)
(1) Université Louis Pasteur et Conservatoire National des
Arts et Metiers (herve.segond@psycho-ulp.u-strasbg.fr)
(2) Conservatoire National des Arts et Metiers (eliana.sampaio@psycho-ulp.u-strasbg.fr)
Abstract: Les dispositifs de substitution sensorielle non invasifs,
destinés à permettre à des sujets aveugles d'accéder
à des informations visuo-spatiales par l’intermédiaire de
modalités sensorielles autres que la vision, ont considérablement
évolué depuis leurs précurseurs que furent la canne
blanche et le Braille. Les évolutions scientifiques, technologiques
et techniques, se sont caractérisées non seulement par le
recours à l’informatique, mais également par la miniaturisation,
et l’utilisation de matériaux amagnétiques offrant l’opportunité
d’études conjointes au niveau comportemental et au niveau des activations
cérébrales.
A l’heure actuelle, on distingue deux catégories essentielles
de systèmes de substitution sensorielle: les systèmes visuo-auditifs,
qui recueillent de l’information sur l’emplacement et la distance des objets,
et les systèmes visuo-tactiles qui fournissent des informations
optiques sur la forme des objets et la profondeur (perspective, parallaxe).
L’utilisation de ces systèmes, par des sujets aveugles de naissance
ou voyants aux yeux bandés, suppose une capacité d’adaptation,
ou plasticité, du système nerveux central.
Les recherches menées par notre équipe, dont les efforts
se concentrent dans le domaine du développement des systèmes
visuo-tactiles, portent sur: 1. les dimensions perceptive et cognitive
inhérentes à la perception de l’espace extra-corporel par
des systèmes sensoriels non visuels (cf. utilisation immédiate
chez le bébé, en raison d’une plasticité cérébrale
importante vs. procédures d’apprentissage requises chez l’adulte),
2. la mesure de « l’acuité » visuo-tactile, meilleure
que celle permise par le système de vision artificielle développé
par l’Institut Dobelle (système invasif connecté directement
au cerveau), 3. le développement des changements au niveau cérébral,
occasionnés par ces dispositifs (en IRMf), 4. les possibilités
de navigation dans l’espace 3D via des informations substitutives visuo-tactiles
(dans un labyrinthe réel 3D).
L’ensemble de ces recherches offrent des perspectives nouvelles pour
la compréhension des mécanismes intermodaux de détection
des invariants perceptivo-moteurs (inhérents au principe de substitution
sensorielle et permettant la reconnaissance des objets perçus),
l’utilisation précoce de ces dispositifs, chez le bébé,
en vue de prévenir les troubles du développement fréquemment
observés chez l’enfant aveugle et l’absence de prise en charge,
et plus généralement, la possibilité pour des sujets
aveugles d’accéder à des informations optiques jusqu’alors
inconnues (cf. profondeur).
"Implications of a 'sensorimotor' theory of visual phenomenality
for change blindness, color perception, sensory substitution and the notion
of space and object."
Kevin O'Regan & Aline Bompas
Laboratoire de Psychologie Expérimentale, Université
René Descartes, 71 avenue Edouart Vaillant,
92774 Boulogne-Billancourt
(oregan@ext.jussieu.fr, aline_bompas@hotmail.com)
http://nivea.psycho.univ-paris5.fr/index.html
Abstract: Under a recent "sensorimotor" theory of visual sensation
(O'Regan & Noë, Behavioral and Brain Sciences, 2001, in press),
the qualitative nature of our visual experience is constituted by our implicit
knowledge of the laws of co-variance linking motor actions and the resulting
sensory changes. One of the implications of this way of thinking about
vision is that information about a visual scene need not be stored in detail
in the brain. All that need be stored is 'recipes' that allow an observer
to check that attended objects are actually present. The phenomenon of
'change blindness' is compatible with this. Another application of the
theory concerns color vision. When the eye moves, or when an object moves,
certain predictable changes occur which are typical of colors. Under the
sensorimotor theory, it is the knowledge of such laws which constitute
color sensation. If this is correct, it should be possible to modify perceived
color by changing these sensorimotor contingencies. Experiments are reported
where we attempt to do this.
Jeudi après-midi
"I. Deducing the dimensionality of space and the nature
of objects: towards a mathematical formulation. II. Human attempts at learning
the contingencies of space"
David Philipona (1), Malika
Auvray (2,3), Kevin O'Regan (3) & J-P
Nadal (4)
(1) Ecole Polytechnique (david.philipona@m4x.org)
(2) Babel@stal, 25 rue du Petit Musc, 75004 Paris (mauvray@babel.fr)
(3) Laboratoire de Psychologie Expérimentale, Université
René Descartes, 71 avenue Edouart
Vaillant, 92774 Boulogne-Billancourt (oregan@ext.jussieu.fr)
(4) Laboratoire de Physique Statistique, Ecole Normale Supérieure
(nadal@ens.fr)
Abstract (à confirmer): We show mathematically that when an
observer or robot moves his body and receives sensory input, he can extract
from the co-variance of the input-output statistics information about dimensionality
of space, and the number of attributes necessary to describe objects within
it. We present some preliminary experimental tests where humans are required
to learn new sensorimotor contingencies.
"Ways of worldmaking: Exploring perception and
behavior in humans inhabiting simple virtual environments"
Georgi Stojanov
Computer Science Department, Electrical Engineering Faculty, SS
Cyril and Methodius University in Skopje, Macedonia (geos@cerera.etf.ukim.edu.mk)
Abstract: The work described here explores the hypothesis that perception
is a proactive process, resulting out of the active stay of the agent in
a given environment. In our usual environments (me here in the office,
looking at the computer monitor, through the window...) where we have long
ago learned the sensory-motor contingencies, it is hard to see the numerous
processes underlying perception. Therefore, the aim was to create an environment
for human subjects where new sensory motor contingencies hold and where
in order to perform a task subjects were to learn and exploit them.
Since 1996 we have created several such environments and some are described
in (Stojanov, G., Gerbino, W., Investigating Perception in Humans Inhabiting
Simple Virtual Environments, European Conference on Visual Perception,
Trieste, 1999). The simplest set-up is the following one: human subjects
sit in front of the computer and are told that they can perform certain
simple actions (finite number of button presses) and that while doing so
they would here auditory stimuli (beeps of varios frequences). Their task
was to succeed to produce a beep of certain frequence (a goal beep, which
is very different from all the other beeps). What subjects don't know is
that in fact the button presses move them in a 2D environment (grid) where
while in different regions they hear different beeps. Moreover, additional
structure is imposed by populating the 2D environment with obstacles which
emmit a distinct beep if one tries to go through them. With dimensions
of the grid of 20x20 subjects are usually able to produce the goal beep
at will ("to come to the goal place") within 30 min.
Apart from the quantitative analysis (e.g. how the number of button
presses decrease after each successful trial) what is interesting is to
explore the strategies people use to solve the task. After the initial
seemengly random button presses, they seem to impose some structure in
the flow of the incoming beeps by trying to repeat certain sequences of
their actions. Indeed, while doing so, they usualy end in some sort of
repetitive cycles of button presses and beeps, and when they "break the
cycle" and again try the same button sequences end up in another cycle.
Eventually, when the cycle they are currently in, contains the goal beep,
the subjects seem to perform a kind of backward chaining learning of the
particular ordering among the cycles. So, when put in a random place of
the 2D environment, they "situate" themselves in some of these cycle and
"go" to the goal region.
Despite of the spatial metaphors that I use to describe the behavior
of the subjects, almost none of them have reported that they had a feeling
of beeing in a 2D maze. What seems to be happening is that subjects learn
isolated chunks of sensory-motor couplings that they can repeat at will,
and then put additional ordering on these chuncs according to their proximity
to the goal beep place in this abstract beep-space.Currently, we are exploring
the effects of the initial instruction on subjects behavior (e.g. "Find
the goal place" instead of "Produce the goal beep").
At the end, I relate this work to the research, from where the whole
idea of simple virtual environments originated. This research was about
artificial agents who were to solve the problem of coming up with a useful
environment model (useful in the sense that it could be used to plan a
path from one place to another) )based solely on the local sensory information.
Unlike in the classical AI they had no access to a bird eye view of their
environment which actually reduces the problem to systematic search. Some
of the resullta are published in ( Stojanov, G., Embodiment as Metaphor:
Metaphorizing-in The Environment in C. Nehaniv (ed.) Lecture Notes in Artificial
Intelligence, Vol. 1562, Springer-Verlag, 1999; Stojanov, G. Expectancy
Theory and Interpretation of EXG curves in the Context of Machine and Biological
Intelligence, PhD Thesis, University in Skopje, Macedonia, 1997. Stojanov,
G., Bozinovski S., Trajkovski, G., Interactionist-Expectative View on Agency
and Learning", IMACS Journal for Mathematics and Computers in Simulation,
North-Holland Publishers, Amsterdam, Vol. 44, 1997; Stojanov, G., Trajkovski,
G., Spatial Representations for Mobile Robots: An Algorithm for Detection
of Learnable and Non-learnable Environments, 1st Congress of Mathematicians
and Computer Scientists in Macedonia, Ohrid, 1996.Stojanov, G., Stefanovski,
S., Bozinovski, S., Expectancy Based Emergent Environment Models for Autonomous
Agents, 5th International Symposium on Automatic Control and Computer Science,
Iasi, Romania, 1995).
"Learning Spatial Concepts by Learning Sensorimotor Contingencies"
James J. Clark, Fatima Drissi
McGill University, Montreal, Canada (clark@cim.mcgill.ca, fatima@cim.mcgill.ca)
Abstract: We propose that the brain uses sets of sensorimotor basis
functions to represent sensorimotor manifolds. Different manifolds represent
different spatial concepts and quantities. Following the sensorimotor contingency
theory of O'Regan and Noe, we propose that learning, and recognition or
perception, is carried out by actively exploring the sensorimotor contingencies
associated with a given spatial concept, under the assumption of a stable
world.
Vendredi matin
"Modeling Rat Place Cells as a Basis for Navigation"
Wulfram Gerstner
Swiss Federal Institute of Technology, Laboratory of Computational
Neuroscience, DI-LCN Lausanne EPFL (wulfram.gerstner@di.epfl.ch)
Abstract: Neurons in the hippocampus of rats respond preferentially
when the animal is at a specific location in the environment. Thus activity
of each single neuron `represents' a certain place in the environment (place
field). Two questions will be addressed in this talk from a modeling point
of view: First, how can we derive place fields from visual and proprioceptive
information? We show that, after some suitable preprocessing, visual and
proprioceptive information? We show that, after some suitable preprocessing,
unsupervised learning yields a stable representation of the environment
by many overlapping place field. Second, how can place fields be used for
navigation? We show that the dense representation by place fields that
results from exploration is an ideal basis for reinforcement learning.
A learned target position can be reached after 5-10 trials. The model is
demonstrated on a Khepera robot with video camera head.
"From view cells and place cells to cognitive map learning:
a robotics perspective"
P. Gaussier (1), A. Revel
(1), J.P. Banquet (2), M. Quoy (1)
(1) Neuro-cybernetic team, Image and Signal processing Lab. (ETIS),
URA 8051, 6 av du Ponceau, 95014 Cergy Pontoise, France (gaussier@ensea.fr,
revel@ensea.fr, quoy@ensea.fr)
http://www-etis.ensea.fr
(2) Neurosciences and modelisation institute, INSERM 483, Jussieu,
Paris (banquet@ccr.jussieu.fr)
Abstract: In this talk a model of the hippocampal system (Hs) that
conciliates the presence of neurons that look like "place cells'' with
the implication of the Hs in other cognitive tasks (complex conditioning
acquisition, memory tasks...) is proposed. Robotics experiments and mathematical
considerations the Hs in other cognitive tasks (complex conditioning acquisition,
memory tasks...) is proposed. Robotics experiments and mathematical considerations
show that ''place cells'' or view ''cells'' can be learned in the perirhinal
and entorhinal cortex. The role of Hs would not be fundamentally dedicated
to navigation or map building. In our model, Hs is used to learn, store
and predict transitions between multimodal states. This transition prediction
mechanism could be important for novelty detection but, above all, crucial
to merge in a single and coherent system planning and sensory-motor functions.
A neural architecture embedding this model has been successfully tested
on an autonomous robot, during navigation and planning in an open environment
showing the interest of using robots has a simulation tool to understand
cognitive systems in the case of complex system/environment dynamics.
"Bayesian elements for perception and space representation"
Pierre Bessière
CNRS - Laboratoire LEIBNIZ, IMAG, Grenoble (Pierre.Bessiere@imag.fr)
Abstract: We will briefly present a Bayesian theory of sensory-motor
systems. We will then develop in some details some experiments done with
mobile robots using this Bayesian approach: sensor fusion, object and situation
recognition, night watchman behaviour, chasing an elusive target, navigation
based on smell information, etc... We will illustrate with this experiments
how some important issues in perception, navigation and space representation
may be addressed without any geometrical models.
"Multisensory spatial representations"
Alexandre Pouget
Brain and Cognitive Science Dept, 9216 MelioraHall, University of
Rochester, Rochester NY 14627 (alex@bcs.rochester.edu)
http://www.bcs.rochester.edu/bcs/people/faculty/alex/
Abstract: Our ability to reach, or move our eyes,
toward a sensory target, whether this target is seen, heard or touched,
indicates that the brain can transform any sensory coordinates into motor
coordinates. Most models assume that these coordinate transforms are broken
down by the nervous system into a series of steps in which the position
of the target is successively recoded into several intermediate frames
of reference (such as head-centered, body-centered and so on). Moreover,
each sensory modality are believed to enter this process at the level of
their primary frame of reference (eg. eye-centered for vision, head-centered
for audition, body-centered for touch). Unfortunately, as we will discuss,
this view is incompatible with behavioral and neurophysiological data.
We will suggest an alternative in which coordinates transforms and multisensory
integration are performed by basis function networks with multidimensional
attractors. We will show that this architecture is consistent with anatomical,
neurophysiological and behavioral data while being computationally optimal.
Vendredi après-midi
"How can properties be ascribed to an object? Comparison
between psychophysical experiments and robots simulations"
Jacques Droulez & Nicolas
Bullot
Laboratoire de Physiologie de la Perception et de l'Action, CNRS-Collège
de France, 11 place Marcelin-Berthelot, 75005 Paris, France (jacques.droulez@college-de-france.fr
,nicolas.bullot@free.fr)
Abstract: Classical experiments in psychophysics investigate the abilities
of perceptual systems to recover information from sensory flow. This kind
of research program often relies on an implicit hypothesis (the psycho-physical
isomorphism hypothesis) according to which the ability to perceive objects
relies on the extraction, binding and storage of different intrinsic properties,
or features, belonging to the distal object. There now exists a growing
literature which criticizes this hyptothesis and postulates that the explanation
of perception requires the study of the interactions between agent and
environment,
and of the different ways sensorimotor information connects to cognition.
Following this trend of research, we will develop the idea that, in perception,
a crucial kind of agent/object-properties – which will be called «current-status
property» – is actively attributed to objects by the agent. The current-status
properties are not object-intrinsic and therefore cannot be directly extracted
from the sensory flow ; they rather indicate the kind of pragmatic role
the object plays within the course of the agent’s action plan. We assume
that such an ascription plays a central role in object identification and
action planning.
To illustrate this hypothesis, we have designed a task based on a Modified
Traveling Salesman Problem (MTSP) which can applied to both psychophysical
experimental protocol and robot simulations. As in standard TSP, the agent
has to find the minimal path connecting a set of targets. In MTSP however,
targets are not labelled and distance between targets are not given as
a primary data to the agent. To solve MTSP, the agent has then to identify
targets by ascribing current-status property (for instance, to distinguish
between «already connected targets» from «not yet reached
targets») and also to extract some relevant intrinsic properties
such as velocity or distances from motion parallax. The results obtained
in psychophysical experiments with up to 10 targets) show that subjects
made only a few mistakes in target identification while the traveled distance
was significantly greater than the optimal solution. These results were
compared to the performances reached by various simulated robots. The simulations
show that internal states corresponding to current-status properties are
required to reach the subject level of performance. Finally, we will discuss
the kind of common reference (pointer-based versus topographical) required
for both object-intrinsic and current-status properties.
"Interactive perception: some implications for metaphysics
and neuroscience"
Erik Myin
Centre for Logic and Philosophy of Science, Department of Philosophy,
Free University Brussels (VUB) (emyin@vub.ac.be)
http://homepages.vub.ac.be/~emyin
Abstract: This presentation has three intertwined aims:
1) to provide a general definition of theories that describe perception
as the exercise of potential for action, such as the 'sensorimotor contingency
theory' (O'Regan and Noë, Behavioral and Brain Sciences (in press);
2) to sketch how such theories require a different metaphysics than
the traditional reductionist one;
3) to outline how such a theory requires a different view of the relation
between neuroscience and perception than the traditional one.
I will argue that the conception of perception as the active exercise
of know-how concerning relations between input and self-movement implies
that perception cannot be identified with lower-level neurobiological,
let alone physical, events. This creates a conflict with both traditional
reductionist metaphysics and with the idea of there being 'neural correlates
for consciousness'. I argue a more satisfactory metaphysics can be found
in 'promiscuous realism' (J. Dupré, The Disorder of Things, Harvard
UP, 1993) and I sketch how the relation between capacity theories of perception
and neuroscience can be reestablished though focusing on neural plasticity
rather than on snapshots of neural activity.
"Neural plasticity and consciousness: a sensorimotor approach"
Alva Noe (1), Susan Hurley
(2)
(1) Department of Philosophy, University of California at Santa
Cruz, Santa Cruz, CA 95064 (anoe@cats.ucsc.edu) ; http://www2.ucsc.edu/people/anoe/
(2) University of Warwick, United Kingdom (s.l.hurley@warwick.ac.uk)
Abstract: Many scientists ask: why is brain activity in this particular
region of cortex experienced as like this rather than like that? - as red
rather than green, say, or as visual rather than auditory? It tends to
be assumed that the answer must depend on intrinsic properties of the brain
activity. We tend to think, that is, that what an experience is like is
the direct result of the activity of populations of brain cells. But perhaps
it is just this assumption that we can explain consciousness in terms of
intrinsic properties of neural activity that is the source of our enduring
puzzlement? In this paper we challenge the idea that the qualitative character
of experience - consciousness - is a phenomenon that can be understood
just in terms of intrinsic properties of neural activity. We propose, on
the basis of considerations about the phenomenon of neural plasticity,
that the qualititative expression of neural activity is determined not
by the intrinsic features of the activity alone, but the way that neural
activity is embedded within the conext of the sensorimotor organization
of the animal. We also address broader metaphysical implications of this
proposal.