Blog

Multijoint movement without internal models

Thomas Buhrmann has been working on a model of arm movement that, contrary to widespread assumptions, can compensate for the complex and dynamic inter-joint torques without the need for a central control using internal models. This work has been just published and can be accessed for free:

Buhrmann T and Di Paolo EA (2014) Spinal circuits can accommodate interaction torques during multijoint limb movements. Front. Comput. Neurosci. 8:144. doi: 10.3389/fncom.2014.00144.

SCOPE

The model shows how a combination of the musculo-skeletal complex non-linear dynamics and spinal control circuits can produce smooth arm movements where the torque produced in one joint due to movement around the other is actively compensated without the need of a central control by the brain. It lends support to the plausibility of alternative hypotheses of motor control, such as the equilibrium-point hypothesis, that do not rely on internal representations or models.

La mente corporizada – A short documentary

Earlier this year I participated in the making of a short documentary on the embodied mind organized by Manuel Bedia at the University of Zaragoza. A version has been around online for a while now, but now there’s a new version with English subtitles.

The embodied mind from Universidad de Zaragoza on Vimeo.

Non-representational sensorimotor knowledge

Close your eyes and follow the contour of the table in front of you. When you reach the end of it, do you think you would be able to continue moving your hand along the same imaginary line as if the table went on a little further? Most people would not have any problem doing this for a wide variety of conditions (body posture, distance and angle with respect to the table, etc.) Given this variety of circumstances, traditional approaches to perception and motor control postulate when we’re no longer in contact with the table, we must be using some form of representation that keeps guiding the arm along the same invisible line in a robust manner.

Model-eps-converted

Together with Thomas Buhrmann, we have demonstrated that representations are not necessarily the only explanation, and that indeed it is possible to attune the movement of your arm to the world without at any point involving any internal models or representations, but simply by a shaping of dynamical sensorimotor transients. The “memory” of the direction of movement is kept in the whole agent-environment system in a way that generalizes across various relative positions and angles of movement.

Manifolds2b-eps-converted

For more information see:

Buhrmann, T. and Di Paolo, E. A. (2014). Non-representational sensorimotor knowledge. In A.P. del Pobil et al. (Eds.): From Animals to Animats 13, Proceedings of the 13th International Conference on Simulation of Adaptive Behavior, SAB 2014, LNAI 8575, pp. 21–31, NY, Springer Verlag.

Piaget, dynamical systems, and how do we learn to perceive something new

Following our recent work on formalizing some aspects of the sensorimotor approach to perception – in particular the notion of sensorimotor contingencies – using dynamical systems theory, we have continued along similar lines and tackled the question of how we ever learn to perceive something new.

The sensorimotor approach proposes that perception is constituted by the possession (and depending on the interpretation, also the enactment) of skilful mastery of sensorimotor regularities, so that in order to perceive something as soft, one must already know how and where one should apply pressure to it. The question that emerges is how do we ever learn to perceive something new if, according to this approach, perception requires already having a sort of sensorimotor mastery. In this way, that which we know how to perceive is perceivable, but that which we don’t know how to perceive could never be perceived because why would we develop new forms of mastery in order to perceive something that we don’t even know it’s there?

The problem has a solution once we admit that the notions of mastery and skill can have degrees. At a subpersonal level it is possible then to build a theory that establishes how we progressively form new sensorimotor capabilities as much as a response to internal norms as through the guidance of the world. An example of such a theory is Piaget’s theory of equilibration.

fnhum-08-00551-g001Our recent paper:

Di Paolo EA, Barandiaran XE, Beaton M and Buhrmann T (2014) Learning to perceive in the sensorimotor approach: Piaget’s theory of equilibration interpreted dynamically. Front. Hum. Neurosci. 8:551. doi: 10.3389/fnhum.2014.00551

offers a reformulation of Piaget’s theory in the language of dynamical systems theory, which allows us to establish a strict compatibility with our previous formalization of sensorimotor contingencies.

We these developments it is now possible to start thinking of more operational notions of mastery, thus contributing to various debates in embodied cognitive science. We see mastery in non-representational terms, as a progression of dynamical relations of equilibration with the world (including the world of others, although this is not directly addressed in this paper).

A genealogy of the notion of “habit”

In collaboration with Xabier Barandiaran, we have embarked some years ago in what at first looked like a simple exercise in map-making. We encountered such different reactions when we mentioned our interest in the concept of habit that it was clear that the word meant very different things to different people. Cognitive scientists and neuroscientists immediately think of habits as blind automatisms, psychologists and psychotherapists think of them as remnants of a developmental history, while social scientists think of them as self-sustaining normative structures of the life world. We thought it would be relatively easy to disentangle these different meanings and connotations of the term. In fact, we found a rich and ever-expanding network of ideas, influences, nuances, expansions and reductions of concepts and even rejections of the notion(s) of habit.

The result is the following map.

habit-map

You can read about how we constructed this map, the literature consulted, and what we make of it here:

Barandiaran XE and Di Paolo EA (2014) A genealogical map of the concept of habit. Front. Hum. Neurosci. 8:522. doi: 10.3389/fnhum.2014.00522.

And you can find the map in other formats following this link: http://barandiaran.net/design/habit-map.

As we suggest towards the end of our mini-review, we think that the time is ripe of a modern notion of habit, not as blind automatisms but as sophisticated, adaptive and self-sustaining structures of sense-making, to re-enter the discourse in psychology, neuroscience and embodied cognitive science.

Frontiers Research Topic on Embodied Intersubjectivity

The Life & Mind Seminar Network

Frontiers in Psychology (section Cognitive Science) has launched a call for papers for a new Research Topic on embodiment and intersubjectivity.

SpecialTopic Image

Topic Editors:

Ezequiel A. Di Paolo, Ikerbasque – Basque Foundation for Science, Spain
Hanne De Jaegher, University of the Basque Country, Spain

Deadline for abstract submission: 17 Jan 2014

Deadline for full article submission: 30 Apr 2014

An important amount of research effort in psychology and neuroscience over the past decades has focused on the problem of social cognition. This problem is understood as how we figure out other minds, relying only on indirect manifestations of other people’s intentional states, which are assumed to be hidden, private and internal. Research on this question has mostly investigated how individual cognitive mechanisms achieve this task. A shift in the internalist assumptions regarding intentional states has expanded…

View original post 418 more words

AVANT Interview, 2012

Hanne De Jaegher and I have been interviewed on our work on enactivism by the open access journal AVANT Volume III, Issue 2/2012 (October-December), ISSN: 2082-6710.

You can download the interview here and Tom Froese’s introduction here.
Image

 

Several other interesting things in this issue. It can be downloaded as a whole.

Tarkovsky’s Stalker and the paradoxes of non-linear decision making

In Andrei Tarkovsky’s 1979 film Stalker three men undertake a perilous trip into the Zone, an off-limits and run-down post-industrial area full of the dangerous but valuable scattered debris left behind by a passing alien visitation (the leftovers of a “roadside picnic” as the title of the original novel by the Strugatsky brothers suggests). It is said that within the Zone there is a room with the power of making one’s innermost desires come true, even the unconscious ones – a ruthlessly rule-governed spot in a land of exception. The road to this room is full of mortal traps, often invisible to the eye. Your body could be crushed with artificial gravity or burned to cinders almost without a warning.

Two of the men, who for different motives want to visit the room, hire the help of a third as a guide, a Stalker. The guide is overcautious as they advance, making the others walk in line and for short stretches at a time. He tests for the presence of traps by throwing metal nuts with long ribbons into the air looking for distortions in their trajectory. At one point they come very close to the building where the room is located and yet the Stalker convinces the other men that they should not enter it directly but they should instead take a very long-winded route leading away from it. The journey is arduous and confusing and the travellers often find themselves stuck confronting the same situations and dilemmas. The route parallels the inner personal journeys of the characters and their own stumbling blocks.

Image

I believe that such a situation is an accurate, if extreme, description of how motivations, rational judgements and emotional reactions interact during ongoing decision-making in real life. It certainly provides a better picture than the way these questions have been investigated in neuroscience, psychology and economics until recently. Our decisions are rarely isolated events, and their interaction is rarely additive. And yet these are the basic assumptions of most research on decision-making and on the interplay between the rational and emotional processes that underlie it. Judging a situation and making a decision is generally embedded within a dynamical context in which a path towards a longer-term goal is being laid down by our own actions.

Consider a doctor prescribing a certain long treatment for a patient. The initial steps of the treatment may still serve a diagnostic function and as a result of one intervention, the doctor decides what the next step should be. Setbacks may as much indicate an insufficiency or an excess provoked by the treatment. And some interventions are deemed too risky to be used at first even though perhaps they would produce the desired effect and most quickly cure the patient. Past decisions, risk judgments and actions interact with not fully known time-extended processes in the world. Real life decision making is a non-linear journey into the unknown, where the unknown is constantly changing in part as a result of our own decisions.

In a recent study, Manuel Bedia from the University of Zaragoza and I have examined this situation using a non-linear model of Antonio Damasio’s Somatic Markers Hypothesis. Our mathematical model considers the case of a journey towards a goal similar to the situation depicted in Stalker in a much more simplified setting. According to Damasio’s hypothesis, and to  other so-called dual-process theories of decision making, the act of judging a situation and deciding on a course of action is not a simple cost-benefit analysis but a context-dependent mixture of rational and affective processes. The question we ask is: what counts as a good balance in this mixture? What factors determine how much we should rely on affective or rational processes?

Our findings were surprising at first. The answer to our question turns out to be highly dependent on whether we consider decisions in a chain as independent events (the traditional linear approach) or allow for interactive coupling between decisions, moves, and situations in the world.

We have found that the effect of primary emotions (often associated with conservative, cautious and protective actions) tend to be larger in non-linear decision chains than one would expect from their effect on single decision events. This results in over-cautiousness and leads to frequent re-visits to stumbling blocks until they are finally overcome. On average we tend to “stay on the spot” in a situation that again re-elicits the same emotional reactions that lead back to it in the first place.

Secondary emotions (somatic associations between past experiences and visceral processes) are conceived as making sense only if their positive effect is larger than the combination of rational and primary emotional decision making. But again, this is true only for an isolated decision event. It turns out that badly attuned somatic markers – for instance, reckless and unreliable gut feelings that often would lead us to bad results (e.g., losing our cool, replying to an annoying email too angrily and too quickly) – can sometimes break the paralysing effect of over-represented cautionary emotions. In other word, in non-linear decision chains, a combination of “bad” decision-making mechanisms (over-cautiousness and recklessness) can lead to a positive chance of successfully attaining your goal. This is what we have shown mathematically.

We might call this approach to decision making “enactive” in that decisions and actions affect the dynamics of the path that needs to be traveled towards a goal, a “path laid down in walking”. This famous phrase by poet Antonio Machado was picked by Francisco Varela and his followers to describe one of the central insights of enactive science: the fact that cognitive agents are participants and not merely observers. Apart from highlighting the importance of this perspective and showing that it makes a concrete, empirically testable difference, the result also has interesting developmental and evolutionary implications. It could help explain how somatic markers can exist in the first place if their positive effect depends on experiential tuning to the world and this tuning can only be poor at the early stages of development. If our result holds in such situations, it would indicate that in fact this is not a problem at all because even poorly attuned somatic markers can have a positive effect.

Childish recklessness is after all one way of breaking out of the paralysis of excessive precaution and learning about the world and making your mark in it. How else are you going to make your way through the Zone and reach that room?

Bedia M and Di Paolo EA (2012). Unreliable gut feelings can lead to correct decisions: The somatic marker hypothesis in non-linear decision chains. Front. Psychology 3:384. doi: 10.3389/fpsyg.2012.00384

The Interactive Brain Hypothesis

A new paper is now available exploring the implications of participatory sense-making for social neuroscience.

The Interactive Brain Hypothesis

Ezequiel Di Paolo & Hanne De Jaegher

Abstract. Enactive approaches foreground the role of interpersonal interaction in explanations of social understanding. This motivates, in combination with a recent interest in neuroscientific studies involving actual interactions, the question of how interactive processes relate to neural mechanisms involved in social understanding. We introduce the Interactive Brain Hypothesis (IBH) in order to help map the spectrum of possible relations between social interaction and neural processes. The hypothesis states that interactive experience and skills play enabling roles in both the development and current function of social brain mechanisms, even in cases where social understanding happens in the absence of immediate interaction. We examine the plausibility of this hypothesis against developmental and neurobiological evidence and contrast it with the widespread assumption that mindreading is crucial to all social cognition. We describe the elements of social interaction that bear most directly on this hypothesis and discuss the empirical possibilities open to social neuroscience. We propose that the link between coordination dynamics and social understanding can be best grasped by studying transitions between states of coordination. These transitions form part of the self-organization of interaction processes that characterize the dynamics of social engagement. The patterns and synergies of this self-organization help explain how individuals understand each other. Various possibilities for role-taking emerge during interaction, determining a spectrum of participation. This view contrasts sharply with the observational stance that has guided research in social neuroscience until recently. We also introduce the concept of readiness to interact to describe the practices and dispositions that are summoned in situations of social significance (even if not interactive). This latter idea links interactive factors to more classical observational scenarios.

Download your free PDF here:

http://www.frontiersin.org/Human_Neuroscience/10.3389/fnhum.2012.00163/abstract

Citation:

Di Paolo E and De Jaegher H (2012) The interactive brain hypothesis. Front. Hum. Neurosci. 6:163. doi:10.3389/fnhum.2012.00163

my new windowless existence

I have heard it said before and, for reasons that will soon become apparent, with increased frequency in the last few months, that architects should be obliged to live and work for a few years in the buildings they design. Nothing exaggerated, just a period sufficiently long to allow them to exercise their empathic skills and think of people other than themselves when they start those drawings.

Never mind the moral obligation, it should be a major safeguard that any intelligent society should put into practice to defend itself from the architectural crimes that, through a combination of strong thirst for notoriety and a very weak concern for their victims (I’m not ruling out stupidity plain and simple), they perpetrate on us.

Needless to say, the same should apply even more strongly to those who commission, select, approve and proudly inaugurate such monstrosities. They should move their offices with us into the belly of the whales they help create.

Until now, I have inhabited offices of different qualities, sometimes a bit too hot in summer or not very airy, or without an inspiring view, sometimes small and with furniture that could be better designed for bipeds. But in general I’ve been satisfied with them. I saw other people’s offices in universities around the world and I never thought myself particularly lucky. It turns out I was. I’m only realising this now because I’ve been forced to move to the recently inaugurated Centro Carlos Santamaría of the University of the Basque Country in San Sebastián, Spain. Thus sharing the same fate as some of my postdocs (who for some reason don’t seem to smile as much as they used to).

For the first time I must confront the joys of working in a window-less, air-conditioned, open plan environment, of grey walls, and furniture of a grey so similar that one must make an effort to make it out to avoid walking into a desk or tripping on the cupboard (my first action will be to glue some yellow/green stripes on particularly risky corners). My desk is in a big, 50 sq m room with 4 desks and several empty bookshelves. I was promised a partition so I can have supervision meetings with some pretend privacy – that was more than 7 months ago and I’m still waiting – but that’s early days by local standards. Like this space, parallel rows of several square, grey, window-less, air-conditioned rooms lie one next to the other, with no way of telling whether it’s day or night, except for a tiny 1 sq m glass sealed opening in the ceiling near the entrance.


The building (photo), which also houses the university library is designed along time-honoured principles for academic buildings, such as the principle that too much natural light thwarts knowledge production, that fresh air induces serious risks such as letting the ideas that should legally be the university’s intellectual property float out freely into the world, that recycled and droning air-conditioning is the best way to keep us alert and creative, and that windows are known to be conducive to suicide in academic circles (this one may be true).

Plan of first story of the building where my new office is. My desk will be located in one of the little squares on the right. On the left part of the library where light is less of a problem. There’s also a little garden in the middle, “far from the noises of traffic” where one could expect to find some peace, except nobody is allowed to step into it – we can stare at it through a glass door.

Perhaps this eco-friendly marvel (lights on: check, air-conditioning on: check – and yes, this is in Spain) should be better appreciated along artistic lines (philistine me). Modern art must be painful, says Zizek, and the architect who designed this building must have heard someone mention this at some cocktail party, because the effort was surely put on the pain, if not on the art (logic not being the architect’s forte). The result looks like the dead carcass of a concrete, legless crab after the seagulls have finished with it. Painful, yes.

What kind of brain damage makes a person capable of commissioning, selecting, and accepting such a working environment for academics? What kind of childhood trauma explains their total lack of foresight (and they’d better claim it was lack of foresight because otherwise we need immediately to raise some more difficult questions). I don’t think it’s fair to put the blame on the architect, since we should expect certain lack of common sense within their cast, especially among those that intend to make a name for themselves in their quest for the oddest, most useless, headline-grabbing form; it’s not their fault and they need society’s understanding and care, institutional if possible. It’s the ones who say yes to this who should humbly apologise. Those who once they realised they were actually commissioning an intellectual sweatshop, just didn’t care, or cared as much a 1 sq m glass un-openable aperture in the ceiling – the architectural zenith of last minute decisions – which lets in only enough photons to find the light switch and the thermostat.

Thank you so much… We needed this because we had it so good until now. This building should carry your name too. A bronze plaque with a list of perpetrators, lest we forget. Because in a few years time, when it looks as silly and ridiculously outmoded from the outside as it now does to those who are actually trying to work inside it, they should prevent you from commissioning another one.