ECA; یک این اکتیویست معماری شناختی بر اساس مدل سازی حسی
|کد مقاله||سال انتشار||مقاله انگلیسی||ترجمه فارسی||تعداد کلمات|
|29562||2013||12 صفحه PDF||سفارش دهید||8675 کلمه|
Publisher : Elsevier - Science Direct (الزویر - ساینس دایرکت)
Journal : Biologically Inspired Cognitive Architectures, Volume 6, October 2013, Pages 46–57
A novel way to model an agent interacting with an environment is introduced, called an Enactive Markov Decision Process (EMDP). An EMDP keeps perception and action embedded within sensorimotor schemes rather than dissociated, in compliance with theories of embodied cognition. Rather than seeking a goal associated with a reward, as in reinforcement learning, an EMDP agent learns to master the sensorimotor contingencies offered by its coupling with the environment. In doing so, the agent exhibits a form of intrinsic motivation related to the autotelic principle ( Steels, 2004), and a value system attached to interactions called interactional motivation. This modeling approach allows the design of agents capable of autonomous self-programming, which provides rudimentary constitutive autonomy—a property that theoreticians of enaction consider necessary for autonomous sense-making (e.g., Froese & Ziemke, 2009). A cognitive architecture is presented that allows the agent to discover, memorize, and exploit spatio-sequential regularities of interaction, called Enactive Cognitive Architecture (ECA). In our experiments, behavioral analysis shows that ECA agents develop active perception and begin to construct their own ontological perspective on the environment.
In cognitive science, there has been a customary and traditional tripartite division of the mind between perception, the control system, and motor action. This view has been nicely dubbed the “classic sandwich model” by Susan Hurley (1998). Many control architectures are built in this way. Since the 1980s there have been many attempts to challenge this traditional picture particularly in the field of robotics (e.g., Brooks, 1991) but also from a more psychological and theoretical perspective (e.g., Hirose, 2002, Shanahan, 2010 and Ziemke, 2001). In particular, the idea emerged that it might be a mistake to consider sensation independently from action and that we should design cognitive systems on the basis of low-level sensorimotor loops that represent sensorimotor patterns of interaction. This intuition gained momentum from other related views such as embodied cognition (e.g., Anderson, 2003 and Holland, 2004), ecological psychology ( Chemero and Turvey, 2007 and Gibson, 1979), sensorimotor theories ( O’Regan and Noë, 2001 and O’Regan, 2012), morphological robotics ( Paul, 2006, Pfeifer and Bongard, 2006 and Pfeifer, 1999), developmental robotics ( Lungarella, Metta, Pfeifer, & Sandini, 2003), and epigenetic robotics ( Berthouze and Ziemke, 2003 and Zlatev, 2001). Here, we introduce a modeling approach that goes a step beyond the notion of low-level sensorimotor loops by simply considering sensorimotor patterns—also called sensorimotor schemes by Piaget (1951)—as the atomic elements manipulated by our algorithms. Varela, Thompson, and Rosch (1991) coined the term enactive perception to suggest that organism and environment are coupled together. The features of the environment to which an organism responds are singled out by the ongoing activity in the organism. The domain that defines this coupling has been called the relational domain (e.g., Froese & Ziemke, 2009). The theory of enaction, initiated by Varela, stresses that the relational domain evolves over the organism’s life in a manner that is codetermined by the organism and the environment. The fact that the relational domain is not predefined makes possible the organism’s constitutive autonomy—the capacity of the organism to “self-constitute its identity” ( Froese & Ziemke, 2009). These authors argue that constitutive autonomy is an important aspect of organisms because it is a precondition of sense-making and intrinsic teleology, and is thus a property that we should seek to obtain in artificial agents. Furthermore, the term enaction also incorporates the idea that perception involves physical activity, or action. A model of reference was offered by O’Regan and Noë’s (2001)sensorimotor contingencies theory. To perceive the world is to master the sensorimotor contingencies between the body and the world. Every sensor modality is characterized by “the structure of the rules governing the sensory changes produced by various motor actions, that is, what we call the sensorimotor contingencies” ( O’Regan & Noë, 2001, p. 941). The enactivist approach suggests modeling a cognitive agent on the basis of sensorimotor interactions with the environment. This paper is an attempt in that direction. In the next section, we introduce a new type of algorithm that does not separate perception from action, called an Enactive Markov Decision Process (EMDP). An EMDP provides a useful conceptual framework for designing agents capable of intrinsically-motivated self-programming as they interact with their environment. We qualify such self-programming as sensorimotor because it consists of learning a series of sensorimotor schemes that are subsequently executed as programs. We argue that sensorimotor self-programming opens the way to constitutive autonomy. While acknowledging that EMDP problems are intractable in the general case, we present two instances in which the coupling with the environment allows the agent to learn to master sensorimotor contingencies within a reasonable frame. The first is called a hierarchical sequential EMDP problem. The second is called a Spatial Enactive Markov Decision Process (SEMDP). A SEMDP is intended to model an agent interacting with an environment that has a Euclidian spatial structure, such as the real world. This work leads us to propose a cognitive architecture dedicated to agents confronted with SEMDP problems, called the Enactive Cognitive Architecture (ECA).
نتیجه گیری انگلیسی
We have simultaneously introduced: (a) a new approach to model an agent interacting with an environment while keeping perception and action embedded (the EMDP and SEMDP formalisms); (b) an approach to self-motivation based on an association of autotelic motivation and interactional motivation; (c) a new cognitive architecture (ECA) to control an agent that learns to fulfill its autotelic and interactional motivation; and (d) a way to assess the agent’s learning through behavioral analysis. We report experiments that show that certain interactions (e.g., feel) become meaningful to the agent because it learns to use them to inform its future behavior. This result demonstrates that the agent learns to perform active perception, that is, the agent actively uses certain interactions as a form of perception to inform its knowledge of the current situation. Additionally, the agent addresses the autonomous ontology construction problem at a rudimentary level. It learns to actively distinguish between two types of phenomena afforded by its environment and to cope with these phenomena by successfully enacting learned sequences of interactions ( Fig. 8). In the description of the architecture, we point out many questions that remain to be addressed in moving towards more sophisticated agents confronted with couplings that offer more complex spatio-sequential regularities of interaction. In its current version, we acknowledge that ECA relies upon too many hard-coded functions, which should ultimately be removed in order to provide the agent with more flexibility to scale up to more complex environments. Some of these functions should be autonomously constructed by the agent, which would leave room for even more constitutive autonomy. In spite of its current limitations, we believe that ECA offers a useful framework in which to study and advance the theory of enaction for the following reasons: (a) ECA uses sensorimotor schemes as the atomic elements of cognition rather than separating perception and action. (b) ECA supports studying how the agent constructs its own ontology of the environment from its experience interacting with it, in sharp contrast to traditional rule-based cognitive architectures that require the modeler to specify the semantics of symbols, which amounts to defining the ontology of the environment a priori. (c) ECA allows implementing self-motivation in the agent. In the future, we envision implementing other behavior-selection mechanisms to generate additional forms of motivation such as curiosity. (d) ECA allows the agent to program itself by learning a series of sensorimotor interactions and executing them as a single composite interaction. Self-programming allows constitutive autonomy, which theoreticians of enaction have identified as an important requirement for autonomous sense-making and intrinsic teleology.