p.113 Embodied representations

I want to begin by sketching out the conception of an embodied representation which Ashby developed in the late 1960s. I should say that it was an extension of his earlier work in Design for a Brain, but that his earlier work was more concerned with promoting certain techniques of analysis. The underlying view of the mind was as a complex system seeking various equilibriums, and emphasised the separation of stable ‘essential variables’ from the dynamic variation of active variables.

p.113 Conant and Ashby (1970) present a compelling case that every good regulator of a system must be a model of that system.

p.114 the regulator can act before the effects are realised. We can call such systems 'proactive'... It follows that such proactive and predictive regulators are in some sense models of the relationships that exist between potential disturbances and regulated systems, at least if they are good regulators.

p.114 The sense of the model employed here is... a working model - it models a system in virtue of its dynamic material actions over time.

p.115 There is a sense in which the proactive system is a model of the potential future states of a system – it is anticipatory or predictive. As such, it must model not only the states of the system it regulates, but the transitions between states – the dynamics of the system. Thus, the regulator must model a dynamic system. In many cases, such as the governor, this need not entail a complex symbolic representation, especially if the regulator is itself a dynamic system.

p.115 the notion of the regulator is fundamentally a matter of control of action. In the absence of action, or at least potential action, it does not make sense to talk about mind, as it is fundamentally bound up with behavior.

p.115 perception and action have equal shares in the structure of embodied representation, and where the role of perception is largely to modulate and regulate action. That is to say that the sensory and the motor are both equally implicated in the feedback loops which regulate behavior... the recognition of the significance of motor control ought to influence how we think about perception

p.115-116 While the individual regulator is a good model for understanding an individual reflex, behaviour is often much more complicated than this. It is not surprising that, in Ashby’s view, a system will need a robust variety of behaviours in order to respond to a complex environment, lest we forget his Law of Requisite Variety (Ashby 1956, p. 207) and it is precisely in the extension and scaling-up of these simple mechanisms to account for the behaviour of the large and complex system of the brain that the real difficulties lay.

p.116 The basis of all such systems, or the atomic mechanism, is the feedback loop of sensation, reflex action and adaptation and he saw that these atomic reflex mechanisms can be built up artificially, or allowed to self-organise naturally, into layers. These layers can form much more complex organism behaviours such as foraging, long-distance navigation and sophisticated multi-step tasks. The use of atomic reflex mechanisms, and their layering, is the basis of recent work in autonomous robotics, called the subsumption architecture.

p.116 The basic insight of Gibson's ecological theory of perception is that even abstract mental representation of distant times and places is built upon the same embodied interactions as simple sensory-motor mechanisms... the structure of visual perception is more likely to be shaped by the features of a creature's body and its interactions with an environment, than it is to be shaped by abstract geometric properties, such as Euclidean geometry.

p.116 the guiding principle of this theory is that the brain developed as an elaborate regulator of muscular control.

p.117 Marvin Minsky (1963) recognized that Ashby's early work on learning mechanisms had led to the widespread use of search procedures 

p.117 Pengi is essentially a programmed mechanism which displays reflexes, reacting directly to the state of its environment, unconditioned by learning or even previous states of the environment (i.e. it has no memory). This is precisely what Ashby had in mind when he describes reflex mechanisms in his later work: a mapping from disturbances to actions.

p.117 we should try instead to build very simple animals with insect-like intelligence and work up... To achieve this goal, Brooks... proposed a new approach which he called the subsumption architecture. The basic idea was that robotic creatures could be built which were quite adept at getting along in the world if we changed our ideas about how they do it... robots should be built as bundles of reflexes.

p.118 [Ashby] It is now known, however, that this property of reacting to combinations and relations between stimuli, is readily obtained from the mechanism, if the mechanism works in stages or levels so that the first level “computes” various functions of the primary stimuli, then the later levels compute functions of these functions, and the final stage acts only if these “computational” processes have resulted in some actual physical event at the penultimate stage. In this way, any defined function over the primary stimuli, however complex or subtle it may be, can be transformed, in a purely mechanistic way, to a physical event suitable to act as physical cause for the instinctive action. The apparent distinction between reflex and instinct were based, mostly unconsciously, on a one-level model: stimulus-to-response, without intermediate processing. (Ashby 1967, p. 101)

We can see in this passage that he recognized the fundamental importance of layering simple mechanisms in order to achieve complex behaviours.

p.118 Researchers working on adaptive multi-layered architectures would be well advised to reread Ashby's papers on adaptation and information flows in large-scale adaptive architectures... learning to regulate motor activities at a high enough level of complexity... will ultimately require a mechanism of coordination and deliberation - consciousness.

p.119 The theory which offered the strongest challenge to the computational theory was James J. Gibson’s ecological theory of perception. Gibson first began to publish his ideas in 1950, and his final formulation came in 1979. This theory, I argue, is an elaboration of the concept I have been calling embodied representation. That is, it takes the relationship between the perceiving system and its environment as primary. And in so doing, it places the proper significance on motor activity – both for its ability to inform the system apart from a single sensation or image, and for the specific ways it which it structures perception of the world. Gibson’s theory is best remembered for introducing the concept of ‘affordances,’ a term he used to describe how the mind perceives the world in terms of the various activities it affords to the body. This is exactly what we should expect once we understand that perception evolved primarily to serve action, i.e. that it is an aspect of embodied representation. I want to take a moment to give a very brief sketch of some critical aspects of Gibson’s theory, before remarking on how it might be extended based upon some additional insights from Ashby’s work.

p.119 the mental representation of space... is... a consequence of our interaction with the world. It is the same for time as it is for space

p.120 There is no such thing as the perception of time, but only the perception of events and locomotions. These events and locomotions, moreover, do not occur in space but in the medium of the environment that is rigid and permanent. Abstract space is a sort of ghost of the surfaces of the world, and abstract time is a ghost of the events of the world. (Gibson 1975, p. 295)

p.120 interactions with the environment, such as movement through it... can lead to representations of things distant in time and space. That is to say, it is bodily activity itself which structures the perception of time and space – the essence of the most sophisticated and complex representations of the world are fundamentally embodied representations.

p.120-121 the information the visual system extracts from the ambient visual array is really just the disturbances and discontinuities in quality, space and time. When these disturbances and discontinuities occur persistently and reliably, they come to be treated as the invariant structures of the perceived world.

  But perception does not end with the information provided by vision. This information must be assimilated with other information, memory, the current state of the body and the potential actions of the body.

p.121 Gibson’s account of unified perception rests on two interdependent notions. The first notion is self-awareness, which consists of proprioception (usually meant to apply to the states of the skeletal muscles) and what he calls egoreception, or an awareness of the internal states of the body. The second notion is that of orientation – the relation between the internal states of the body and the external states of the environment.

p.122 we need to understand that as a regulator improves, it actually deals with less information, rather than more. A naıve, untrained regulator will not yet have learned which aspects of the environment are relevant to it. Thus, it must pay attention to as many aspects as it can. One significant part of learning is to discover which set of messages are the relevant ones that the regulator needs to select among.

p.123 Ashby recognised that we should not think of robots in different terms than we do human brains. When one considers each from the perspective of performing a task involving controlled action, the processing of information will be the same in each. This is the very essence of information processing in the brain

p.125 the vital triangle consists of the motor cortex, sensory cortex, and short term memory. Through the structure of the multiple-feedback loops and their timing, it can be shown that the brain constantly imagines possible motor activities, but the sensory and memory areas can veto these plans before the signals are sent to the nerve spindles which coordinate the actual muscular contractions. When we read, and when we think with words, we are vocalising internally, or sub-vocalising, without actually moving our lips, larynx and breath or producing sounds. The same is true, on this view, for all thought – it is motor activity not fully realised. When we imagine running, our motor areas are planning out running movements, but our senses tell us we are sitting, and our memory reminds us we are in a lecture and running is inappropriate behaviour, and so the behaviour is suppressed. Everything which is conscious is a potential action, potential perception, or recalled memory of some kind. Even the most fanciful and impossible acts of the imagination are only conceivable insofar as they are potential actions and perceptions of the body.

p.126  the conscious creatures imagine various sorts of consequences of their current actions with respect to their intentions, and make choices about what to do and this happens at time scales ranging from microseconds in the case of the motor control adjustments of a tennis racquet angle or the steering wheel of a car in traffic, to minutes, hours or days in the more reasoned deliberation of such life choices as which car to buy or career to pursue, and that can actually modify the intentional structure of future actions.

  All of this is highly time-dependent.

p.126 Cotterill goes further to argue that consciousness actually arose as a mechanism to coordinate the selection of actions in a timely manner. The basic thrust of the argument is that having a mechanism like consciousness has an evolutionary advantage for two reasons. First, it allows much more rapid forms of learning. A conscious circuit can learn from a single experience, if it is important enough, by focusing its attention on the event, rehearsing it in the imagination, and considering alternative responses and their potential consequences. Second, it allows the system to actively explore its environment, rather than merely react to it. The conscious being can probe for stimuli, and seek out information from the environment. This active form of perception is still poorly understood from a computational perspective