We suggest that the influence of biology in ‘biologically inspired robotics’ can be embraced at a... more We suggest that the influence of biology in ‘biologically inspired robotics’ can be embraced at a deeper level than is typical, if we adopt an enactive approach that moves the focus of interest from how problems are solved to how problems emerge in the first place. In addition to being inspired by mechanisms found in natural systems or by evolutionary design principles directed at solving problems posited by the environment, we can take inspiration from the precarious, self-maintaining organization of living systems to investigate forms of cognition that are also precarious and self-maintaining and that thus also, like life, have their own problems that must be be addressed if they are to persist. In this vein, we use a simulation to explore precarious, self-reinforcing sensorimotor habits as a building block for a robot's behavior. Our simulations of simple robots controlled by an Iterative Deformable Sensorimotor Medium demonstrate the spontaneous emergence of different habits...
Recent empirical work has characterized motile oil droplets —small, self-propelled oil droplets w... more Recent empirical work has characterized motile oil droplets —small, self-propelled oil droplets whose active surface chemistry moves them through their aqueous environment. Previous work has evaluated in detail the fluid dynamics underlying the motility of these droplets. This paper introduces a new computational model that is used to evaluate the behaviour of these droplets as a form of viability-based adaptive self-preservation , whereby (i) the mechanism of motility causes motion towards the conditions beneficial to that mechanism’s persistence; and (ii) the behaviour automatically adapts to compensate when the motility mechanism’s ideal operating conditions change. The model simulates a motile oil droplet as a disc that moves through a two-dimensional spatial environment containing diffusing chemicals. The concentration of reactants on its surface change by way of chemical reactions, diffusion, Marangoni flow (the equilibriation of surface tension) and exchange with the droplet’...
It has been shown that it is possible to transform a well-stirred chemical medium into a logic ga... more It has been shown that it is possible to transform a well-stirred chemical medium into a logic gate simply by varying the chemistry's external conditions (feed rates, lighting conditions, etc.). We extend this work, showing that the same method can be generalized to spatially extended systems. We vary the external conditions of a well-known chemical medium (a cubic autocatalytic reaction–diffusion model), so that different regions of the simulated chemistry are operating under particular conditions at particular times. In so doing, we are able to transform the initially uniform chemistry, not just into a single logic gate, but into a functionally integrated network of diverse logic gates that operate as a basic computational circuit known as a full-adder.
A habit is formed through the repeated enactment of sensorimotor regularities created and maintai... more A habit is formed through the repeated enactment of sensorimotor regularities created and maintained by means of plastic changes on the mechanism that brings them about. This precarious, self-maintaining sensorimotor organization is known as sensorimotor autonomy. One can imagine how some habits would be better suited to the maintenance of a biological individual. Evolution can bias the parameters of the plastic medium over which sensorimotor autonomy emerge so as to be beneficial to biological autonomy. In this work, we show that varying some parameters that bring about plastic changes in the behavior-generating medium, different sensorimotor individuals emerge. The simulation consists of a simple robot coupled with a habit-based controller with a random-based exploratory phase in a one-dimensional environment. The results show that, varying the parameters of such a phase, qualitative different habits emerge characterized by static, monotonic and oscillatory behaviors. Quantitative variations of the oscillatory behavior are also shown using the frequencies distribution obtained from the motor time series of the formed habits. The results are interpreted in terms of how the sensorimotor habitat could emerge from the random traversing of the sensorimotor environment. Finally, a comparison between this model and the skin brain thesis is presented.
Introduction We design a novel dynamical system of a protocell (PC) that exhibits metabolism-base... more Introduction We design a novel dynamical system of a protocell (PC) that exhibits metabolism-based behavior, based on a previous model developed by Egbert et al. (2009). The original model was instantiated in an environment of artificial chemistry, and was used to explore how a system could modulate its behaviour in response to the implicit viability that arose from the system itself. It was simulated on a particulate level; i.e. with the simulation of spatially embedded particles in a two-dimensional environment, undergoing Brownian motion. The PC consisted of a membrane enclosing various metabolites, and would demonstrate metabolism-based behavior that would maintain its viability. We recreate this model using ordinary differential equations (ODEs), which leads to some simplifications. The concentrations of various metabolites, as well as the spatial location, become functions of time. We study the various behaviors that emerge from the interaction of the PC with two food sources, both necessary to produce and sustain motility, so another aspect of the simplification results in us using only one spatial dimension. However, having the model as a set of ODEs allows us to use the rich tools of dynamical systems analysis to see how various behaviours vary with the alteration of parameters. Further, we investigate the health of these behaviors using the concept of a virtual gradient.
In the enactivist framework, habits are precarious, selfsustaining, and self-individuating sensor... more In the enactivist framework, habits are precarious, selfsustaining, and self-individuating sensorimotor structures: they are a first approximation of autonomous sensorimotor entities. We present a prototype computational model which demonstrates a relatively simple mechanism for facilitating the emergence of such habits in robots. At its core this model is a system which retains a history of sensorimotor sequences which are compared and re-enacted by the controller as a function of the recent sensorimotor activity of the controlled robot. To demonstrate an application of this model concretely, we also present a minimal cognition task loosely inspired by the role of sensorimotor contingencies in human colour perception. This task requires that a robot maintains a set of particular sensorimotor coordinations which allow it to respond to different objects appropriately, influenced by an evolved behavioural history.
This is a report on the Biological Foundations of Enactivism Workshop, which was held as part of ... more This is a report on the Biological Foundations of Enactivism Workshop, which was held as part of Artificial Life XV. The workshop aimed to revisit enactivism's contributions to biology and to revitalize the discussion of autonomy with the goal of grounding it in quantitative definitions based in observable phenomena. This report summarizes some of the important issues addressed in the workshop's talks and discussions, which include how to identify emergent individuals out of an environmental background, what the roles of autonomy and normativity are in biological theory, how new autonomous agents can spontaneously emerge at the origins of life, and what science can say about subjective experience.
Proceedings of the 14th European Conference on Artificial Life ECAL 2017, Sep 1, 2017
Lag is a well recognized phenomenon among both neuroscientists and engineers, with nervous tissue... more Lag is a well recognized phenomenon among both neuroscientists and engineers, with nervous tissues, sensors, actuators and other materials often demonstrating non-negligible lagged influences. A primary focus in evolutionary robotics is the dynamical nature of cognition, but the most common approaches-e. g. evolved continuous-time recurrent neural networks (CTRNN)-employ systems of ordinary differential equations that cannot directly capture lagged influence. Engineers, control-theorists, and neuroscientists often view lag as a problem that needs to be compensated for or avoided, but in this work, we present the first stages of our investigation into how lag can be functional, i. e. can underlie 'intelligent' behaviours. To do so, we follow the evolutionary robotics method, using a genetic algorithm to optimise the parameters of a controller that is coupled to a simulated robot, and then performing dynamical analysis on the most successful system identified. Unlike previous ER work, the controller is modelled using delay differential equations (DDE), so as to be able to capture lagged influence. The evolved controller is highly constrained, consisting of one modeled 'neuron' with a single lagged recurrent connection, so as to force the system to use lag as part of its solution. The artificial evolution identifies a high-quality solution, and we present our initial dynamical systems analysis of that individual.
In the 1950s, the famous cyberneticists Gordon Pask and Stafford Beer conducted a series of remar... more In the 1950s, the famous cyberneticists Gordon Pask and Stafford Beer conducted a series of remarkable electrochemical deposition experiments. By applying an electric potential across electrodes submerged in an acidic solution of ferrous sulfate, they could bias the growth of electrochemical deposition so as to form functional structures including sensory structures capable of distinguishing between different sounds. Unfortunately, the details of their apparatus and methods are unavailable. As a consequence, their experiment has not been replicated, and the precise mechanisms underlying their results remain unknown. As preliminary steps toward recreating their remarkable results, this paper presents a new computational model that simulates the growth and decay of dendritic structures similar to those investigated by Beer & Pask. We use this model to demonstrate a plausible mechanism through which an electrochemical system of this kind could respond to a reinforcement signal. More specifically, we investigate three strategies for varying the applied electrical current so as to guide the formation of structures into target forms. Each presented strategy succeeds at influencing the growth of the structure, with the most successful strategy involving a 'constant-current' feedback mechanism combined with an externally driven oscillation. In the discussion, we compare the adaptation of these structures with various biological adaptive processes, including evolution and metabolism-based adaptive behaviour.
Agency is an under-investigated foundational concept in understanding natural minds and how they ... more Agency is an under-investigated foundational concept in understanding natural minds and how they differ from existing artificial forms of intelligence. To address this, Barandiaran et al. (2009) outlined a provisional definition of minimal agency, based upon three criteria: autonomous individuality; asymmetrical agent-environment interaction; and norm-driven modulation of that interaction. The first part of this paper reviews this definition, drawing attention to the interaction between interactional asymmetry and normativity. The definition is then applied to self-maintaining sensorimotor dynamics observed in a computational model. This has two broad goals: (i) improving our understanding of Barandiaran et al.'s definition of agency and how it could be applied to sensorimotor dynamics; and (ii) improving our understanding of the agent-like structures observed in a simulation of a simple robot whose sensors and motors are coupled to an iterant deformable sensorimotor medium (IDSM). I argue that specific structures within the simulation qualify as autonomous individuals and that these individuals can adapt to environmental changes in a way that benefits their viability. The nature of this adaptation is then examined by comparison to metabolism-independent and metabolism-based form of bacterial chemotaxis.
Life and other dissipative structures involve nonlinear dynamics that are not amenable to convent... more Life and other dissipative structures involve nonlinear dynamics that are not amenable to conventional analysis. Advances are being made in theory, modeling, and simulation techniques, but we do not have general principles for designing, controlling, stabilizing, or eliminating these systems. There is thus a need for tools that can transform high-level descriptions of these systems into useful guidance for their modification and design. In this article we introduce new methods for quantifying the viability of dissipative structures. We then present an information-theoretical approach for evaluating the quality of viability indicators, measurable quantities that covary with, and thus can be used to predict or influence, a system's viability.
Engineers, control theorists, and neuroscientists often view the delay imposed by finite signal p... more Engineers, control theorists, and neuroscientists often view the delay imposed by finite signal propagation velocities as a problem that needs to be compensated for or avoided. In this article, we consider the alternative possibility that in some cases, signal delay can be used functionally, that is, as an essential component of a cognitive system. To investigate this idea, we evolve a minimal robot controller to solve a basic stimulus-distinction task. The controller is constrained so that the solution must utilize a delayed recurrent signal. Different from previous evolutionary robotics studies, our controller is modeled using delay differential equations, which (unlike the ordinary differential equations of conventional continuous-time recurrent neural networks) can accurately capture delays in signal propagation. We analyze the evolved controller and its interaction with its environment using classical dynamical systems techniques. The analysis shows what kinds of invariant sets...
The iterant deformable sensorimotor medium (IDSM) is a controller that has been used to study hab... more The iterant deformable sensorimotor medium (IDSM) is a controller that has been used to study habits construed as self-sustaining patters of sensorimotor activity. To understand the dynamics of this controller, we investigate a heavily simplified variation of it called a node-based sensorimotor-to-motor map (NB-SMM). This deterministic, stateless, continuous-time controller coupled to a minimalistic robot and environment demonstrates six distinct categories of behaviour, including an ability to distinguish between the two sides of a symmetric stimulus, suggesting that controllers based purely on sensorimotor-state to motor mappings may be more capable than intuition first suggests. As the number of nodes increases, the potential behavioural complexity also increases. With two nodes, cycles become possible, along with systems which produce multiple behaviours depending upon initial conditions. This hints at the potential behavioural complexity of a system with many more nodes and pro...
Genetic mutations, infection by parasites or symbionts, and other events can transform the way th... more Genetic mutations, infection by parasites or symbionts, and other events can transform the way that an organism's internal state changes in response to a given environment. We use a minimalistic computational model to support an argument that by behaving "interoceptively," i.e. responding to internal state rather than to the environment, organisms can be robust to these organisationaltransformations. We suggest that the robustness of interoceptive behaviour is due, in part, to the asymmetrical relationship between an organism and its environment, where the latter more substantially influences the former than vice versa. This relationship means that interoceptive behaviour can respond to the environment, the internal state and the interaction between the two, while exteroceptive behaviour can only respond to the environment. We discuss the possibilities that (i) interoceptive behaviour may play an important role of facilitating adaptive evolution (especially in the early evolution of primitive life) and (ii) interoceptive mechanisms could prove useful in efforts to create more robust synthetic life-forms.
The viability of a living system is a non-trivial concept, yet it is often highly simplified in m... more The viability of a living system is a non-trivial concept, yet it is often highly simplified in models of adaptive behavior. What is lost in this abstraction? How do viability conditions appear in the first place? In order to address these questions we present a new model of an autopoietic or protocellular system simulated at the molecular level. We propose a measurement for the viability of the system and analyze the 'viability condition' that becomes evident when using this measurement. We observe how the system behaves in relation to this condition, generating instances of chemotaxis, behavioural preferences and simple (yet not trivial) examples of action selection. The model permits the formulation of a number of conclusions regarding the nature of viability conditions and adaptive behaviour modulated by metabolic processes.
We argue that the significance of the spatial boundary in autopoiesis has been overstated. It has... more We argue that the significance of the spatial boundary in autopoiesis has been overstated. It has the important task of distinguishing a living system as a unity in space but should not be seen as playing the additional role of delimiting the processes that make up the autopoietic system. We demonstrate the relevance of this to a current debate about the compatibility of the extended mind hypothesis with the enactive approach and show that a radically extended interpretation of autopoiesis was intended in one of the original works on the subject. Additionally we argue that the definitions of basic terms in the autopoietic literature can and should be made more precise, and we make some progress towards such a goal.
Since the pioneering work by Julius Adler in the 1960's, bacterial chemotaxis has been predominan... more Since the pioneering work by Julius Adler in the 1960's, bacterial chemotaxis has been predominantly studied as metabolism-independent. All available simulation models of bacterial chemotaxis endorse this assumption. Recent studies have shown, however, that many metabolism-dependent chemotactic patterns occur in bacteria. We hereby present the simplest artificial protocell model capable of performing metabolism-based chemotaxis. The model serves as a proof of concept to show how even the simplest metabolism can sustain chemotactic patterns of varying sophistication. It also reproduces a set of phenomena that have recently attracted attention on bacterial chemotaxis and provides insights about alternative mechanisms that could instantiate them. We conclude that relaxing the metabolism-independent assumption provides important theoretical advances, forces us to rethink some established pre-conceptions and may help us better understand unexplored and poorly understood aspects of bacterial chemotaxis.
We suggest that the influence of biology in ‘biologically inspired robotics’ can be embraced at a... more We suggest that the influence of biology in ‘biologically inspired robotics’ can be embraced at a deeper level than is typical, if we adopt an enactive approach that moves the focus of interest from how problems are solved to how problems emerge in the first place. In addition to being inspired by mechanisms found in natural systems or by evolutionary design principles directed at solving problems posited by the environment, we can take inspiration from the precarious, self-maintaining organization of living systems to investigate forms of cognition that are also precarious and self-maintaining and that thus also, like life, have their own problems that must be be addressed if they are to persist. In this vein, we use a simulation to explore precarious, self-reinforcing sensorimotor habits as a building block for a robot's behavior. Our simulations of simple robots controlled by an Iterative Deformable Sensorimotor Medium demonstrate the spontaneous emergence of different habits...
Recent empirical work has characterized motile oil droplets —small, self-propelled oil droplets w... more Recent empirical work has characterized motile oil droplets —small, self-propelled oil droplets whose active surface chemistry moves them through their aqueous environment. Previous work has evaluated in detail the fluid dynamics underlying the motility of these droplets. This paper introduces a new computational model that is used to evaluate the behaviour of these droplets as a form of viability-based adaptive self-preservation , whereby (i) the mechanism of motility causes motion towards the conditions beneficial to that mechanism’s persistence; and (ii) the behaviour automatically adapts to compensate when the motility mechanism’s ideal operating conditions change. The model simulates a motile oil droplet as a disc that moves through a two-dimensional spatial environment containing diffusing chemicals. The concentration of reactants on its surface change by way of chemical reactions, diffusion, Marangoni flow (the equilibriation of surface tension) and exchange with the droplet’...
It has been shown that it is possible to transform a well-stirred chemical medium into a logic ga... more It has been shown that it is possible to transform a well-stirred chemical medium into a logic gate simply by varying the chemistry's external conditions (feed rates, lighting conditions, etc.). We extend this work, showing that the same method can be generalized to spatially extended systems. We vary the external conditions of a well-known chemical medium (a cubic autocatalytic reaction–diffusion model), so that different regions of the simulated chemistry are operating under particular conditions at particular times. In so doing, we are able to transform the initially uniform chemistry, not just into a single logic gate, but into a functionally integrated network of diverse logic gates that operate as a basic computational circuit known as a full-adder.
A habit is formed through the repeated enactment of sensorimotor regularities created and maintai... more A habit is formed through the repeated enactment of sensorimotor regularities created and maintained by means of plastic changes on the mechanism that brings them about. This precarious, self-maintaining sensorimotor organization is known as sensorimotor autonomy. One can imagine how some habits would be better suited to the maintenance of a biological individual. Evolution can bias the parameters of the plastic medium over which sensorimotor autonomy emerge so as to be beneficial to biological autonomy. In this work, we show that varying some parameters that bring about plastic changes in the behavior-generating medium, different sensorimotor individuals emerge. The simulation consists of a simple robot coupled with a habit-based controller with a random-based exploratory phase in a one-dimensional environment. The results show that, varying the parameters of such a phase, qualitative different habits emerge characterized by static, monotonic and oscillatory behaviors. Quantitative variations of the oscillatory behavior are also shown using the frequencies distribution obtained from the motor time series of the formed habits. The results are interpreted in terms of how the sensorimotor habitat could emerge from the random traversing of the sensorimotor environment. Finally, a comparison between this model and the skin brain thesis is presented.
Introduction We design a novel dynamical system of a protocell (PC) that exhibits metabolism-base... more Introduction We design a novel dynamical system of a protocell (PC) that exhibits metabolism-based behavior, based on a previous model developed by Egbert et al. (2009). The original model was instantiated in an environment of artificial chemistry, and was used to explore how a system could modulate its behaviour in response to the implicit viability that arose from the system itself. It was simulated on a particulate level; i.e. with the simulation of spatially embedded particles in a two-dimensional environment, undergoing Brownian motion. The PC consisted of a membrane enclosing various metabolites, and would demonstrate metabolism-based behavior that would maintain its viability. We recreate this model using ordinary differential equations (ODEs), which leads to some simplifications. The concentrations of various metabolites, as well as the spatial location, become functions of time. We study the various behaviors that emerge from the interaction of the PC with two food sources, both necessary to produce and sustain motility, so another aspect of the simplification results in us using only one spatial dimension. However, having the model as a set of ODEs allows us to use the rich tools of dynamical systems analysis to see how various behaviours vary with the alteration of parameters. Further, we investigate the health of these behaviors using the concept of a virtual gradient.
In the enactivist framework, habits are precarious, selfsustaining, and self-individuating sensor... more In the enactivist framework, habits are precarious, selfsustaining, and self-individuating sensorimotor structures: they are a first approximation of autonomous sensorimotor entities. We present a prototype computational model which demonstrates a relatively simple mechanism for facilitating the emergence of such habits in robots. At its core this model is a system which retains a history of sensorimotor sequences which are compared and re-enacted by the controller as a function of the recent sensorimotor activity of the controlled robot. To demonstrate an application of this model concretely, we also present a minimal cognition task loosely inspired by the role of sensorimotor contingencies in human colour perception. This task requires that a robot maintains a set of particular sensorimotor coordinations which allow it to respond to different objects appropriately, influenced by an evolved behavioural history.
This is a report on the Biological Foundations of Enactivism Workshop, which was held as part of ... more This is a report on the Biological Foundations of Enactivism Workshop, which was held as part of Artificial Life XV. The workshop aimed to revisit enactivism's contributions to biology and to revitalize the discussion of autonomy with the goal of grounding it in quantitative definitions based in observable phenomena. This report summarizes some of the important issues addressed in the workshop's talks and discussions, which include how to identify emergent individuals out of an environmental background, what the roles of autonomy and normativity are in biological theory, how new autonomous agents can spontaneously emerge at the origins of life, and what science can say about subjective experience.
Proceedings of the 14th European Conference on Artificial Life ECAL 2017, Sep 1, 2017
Lag is a well recognized phenomenon among both neuroscientists and engineers, with nervous tissue... more Lag is a well recognized phenomenon among both neuroscientists and engineers, with nervous tissues, sensors, actuators and other materials often demonstrating non-negligible lagged influences. A primary focus in evolutionary robotics is the dynamical nature of cognition, but the most common approaches-e. g. evolved continuous-time recurrent neural networks (CTRNN)-employ systems of ordinary differential equations that cannot directly capture lagged influence. Engineers, control-theorists, and neuroscientists often view lag as a problem that needs to be compensated for or avoided, but in this work, we present the first stages of our investigation into how lag can be functional, i. e. can underlie 'intelligent' behaviours. To do so, we follow the evolutionary robotics method, using a genetic algorithm to optimise the parameters of a controller that is coupled to a simulated robot, and then performing dynamical analysis on the most successful system identified. Unlike previous ER work, the controller is modelled using delay differential equations (DDE), so as to be able to capture lagged influence. The evolved controller is highly constrained, consisting of one modeled 'neuron' with a single lagged recurrent connection, so as to force the system to use lag as part of its solution. The artificial evolution identifies a high-quality solution, and we present our initial dynamical systems analysis of that individual.
In the 1950s, the famous cyberneticists Gordon Pask and Stafford Beer conducted a series of remar... more In the 1950s, the famous cyberneticists Gordon Pask and Stafford Beer conducted a series of remarkable electrochemical deposition experiments. By applying an electric potential across electrodes submerged in an acidic solution of ferrous sulfate, they could bias the growth of electrochemical deposition so as to form functional structures including sensory structures capable of distinguishing between different sounds. Unfortunately, the details of their apparatus and methods are unavailable. As a consequence, their experiment has not been replicated, and the precise mechanisms underlying their results remain unknown. As preliminary steps toward recreating their remarkable results, this paper presents a new computational model that simulates the growth and decay of dendritic structures similar to those investigated by Beer & Pask. We use this model to demonstrate a plausible mechanism through which an electrochemical system of this kind could respond to a reinforcement signal. More specifically, we investigate three strategies for varying the applied electrical current so as to guide the formation of structures into target forms. Each presented strategy succeeds at influencing the growth of the structure, with the most successful strategy involving a 'constant-current' feedback mechanism combined with an externally driven oscillation. In the discussion, we compare the adaptation of these structures with various biological adaptive processes, including evolution and metabolism-based adaptive behaviour.
Agency is an under-investigated foundational concept in understanding natural minds and how they ... more Agency is an under-investigated foundational concept in understanding natural minds and how they differ from existing artificial forms of intelligence. To address this, Barandiaran et al. (2009) outlined a provisional definition of minimal agency, based upon three criteria: autonomous individuality; asymmetrical agent-environment interaction; and norm-driven modulation of that interaction. The first part of this paper reviews this definition, drawing attention to the interaction between interactional asymmetry and normativity. The definition is then applied to self-maintaining sensorimotor dynamics observed in a computational model. This has two broad goals: (i) improving our understanding of Barandiaran et al.'s definition of agency and how it could be applied to sensorimotor dynamics; and (ii) improving our understanding of the agent-like structures observed in a simulation of a simple robot whose sensors and motors are coupled to an iterant deformable sensorimotor medium (IDSM). I argue that specific structures within the simulation qualify as autonomous individuals and that these individuals can adapt to environmental changes in a way that benefits their viability. The nature of this adaptation is then examined by comparison to metabolism-independent and metabolism-based form of bacterial chemotaxis.
Life and other dissipative structures involve nonlinear dynamics that are not amenable to convent... more Life and other dissipative structures involve nonlinear dynamics that are not amenable to conventional analysis. Advances are being made in theory, modeling, and simulation techniques, but we do not have general principles for designing, controlling, stabilizing, or eliminating these systems. There is thus a need for tools that can transform high-level descriptions of these systems into useful guidance for their modification and design. In this article we introduce new methods for quantifying the viability of dissipative structures. We then present an information-theoretical approach for evaluating the quality of viability indicators, measurable quantities that covary with, and thus can be used to predict or influence, a system's viability.
Engineers, control theorists, and neuroscientists often view the delay imposed by finite signal p... more Engineers, control theorists, and neuroscientists often view the delay imposed by finite signal propagation velocities as a problem that needs to be compensated for or avoided. In this article, we consider the alternative possibility that in some cases, signal delay can be used functionally, that is, as an essential component of a cognitive system. To investigate this idea, we evolve a minimal robot controller to solve a basic stimulus-distinction task. The controller is constrained so that the solution must utilize a delayed recurrent signal. Different from previous evolutionary robotics studies, our controller is modeled using delay differential equations, which (unlike the ordinary differential equations of conventional continuous-time recurrent neural networks) can accurately capture delays in signal propagation. We analyze the evolved controller and its interaction with its environment using classical dynamical systems techniques. The analysis shows what kinds of invariant sets...
The iterant deformable sensorimotor medium (IDSM) is a controller that has been used to study hab... more The iterant deformable sensorimotor medium (IDSM) is a controller that has been used to study habits construed as self-sustaining patters of sensorimotor activity. To understand the dynamics of this controller, we investigate a heavily simplified variation of it called a node-based sensorimotor-to-motor map (NB-SMM). This deterministic, stateless, continuous-time controller coupled to a minimalistic robot and environment demonstrates six distinct categories of behaviour, including an ability to distinguish between the two sides of a symmetric stimulus, suggesting that controllers based purely on sensorimotor-state to motor mappings may be more capable than intuition first suggests. As the number of nodes increases, the potential behavioural complexity also increases. With two nodes, cycles become possible, along with systems which produce multiple behaviours depending upon initial conditions. This hints at the potential behavioural complexity of a system with many more nodes and pro...
Genetic mutations, infection by parasites or symbionts, and other events can transform the way th... more Genetic mutations, infection by parasites or symbionts, and other events can transform the way that an organism's internal state changes in response to a given environment. We use a minimalistic computational model to support an argument that by behaving "interoceptively," i.e. responding to internal state rather than to the environment, organisms can be robust to these organisationaltransformations. We suggest that the robustness of interoceptive behaviour is due, in part, to the asymmetrical relationship between an organism and its environment, where the latter more substantially influences the former than vice versa. This relationship means that interoceptive behaviour can respond to the environment, the internal state and the interaction between the two, while exteroceptive behaviour can only respond to the environment. We discuss the possibilities that (i) interoceptive behaviour may play an important role of facilitating adaptive evolution (especially in the early evolution of primitive life) and (ii) interoceptive mechanisms could prove useful in efforts to create more robust synthetic life-forms.
The viability of a living system is a non-trivial concept, yet it is often highly simplified in m... more The viability of a living system is a non-trivial concept, yet it is often highly simplified in models of adaptive behavior. What is lost in this abstraction? How do viability conditions appear in the first place? In order to address these questions we present a new model of an autopoietic or protocellular system simulated at the molecular level. We propose a measurement for the viability of the system and analyze the 'viability condition' that becomes evident when using this measurement. We observe how the system behaves in relation to this condition, generating instances of chemotaxis, behavioural preferences and simple (yet not trivial) examples of action selection. The model permits the formulation of a number of conclusions regarding the nature of viability conditions and adaptive behaviour modulated by metabolic processes.
We argue that the significance of the spatial boundary in autopoiesis has been overstated. It has... more We argue that the significance of the spatial boundary in autopoiesis has been overstated. It has the important task of distinguishing a living system as a unity in space but should not be seen as playing the additional role of delimiting the processes that make up the autopoietic system. We demonstrate the relevance of this to a current debate about the compatibility of the extended mind hypothesis with the enactive approach and show that a radically extended interpretation of autopoiesis was intended in one of the original works on the subject. Additionally we argue that the definitions of basic terms in the autopoietic literature can and should be made more precise, and we make some progress towards such a goal.
Since the pioneering work by Julius Adler in the 1960's, bacterial chemotaxis has been predominan... more Since the pioneering work by Julius Adler in the 1960's, bacterial chemotaxis has been predominantly studied as metabolism-independent. All available simulation models of bacterial chemotaxis endorse this assumption. Recent studies have shown, however, that many metabolism-dependent chemotactic patterns occur in bacteria. We hereby present the simplest artificial protocell model capable of performing metabolism-based chemotaxis. The model serves as a proof of concept to show how even the simplest metabolism can sustain chemotactic patterns of varying sophistication. It also reproduces a set of phenomena that have recently attracted attention on bacterial chemotaxis and provides insights about alternative mechanisms that could instantiate them. We conclude that relaxing the metabolism-independent assumption provides important theoretical advances, forces us to rethink some established pre-conceptions and may help us better understand unexplored and poorly understood aspects of bacterial chemotaxis.
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Papers by Matthew Egbert